JPWO2006070542A1 - COMMUNICATION DEVICE, STORAGE MEDIUM, INTEGRATED CIRCUIT, AND COMMUNICATION SYSTEM - Google Patents

Abstract

An object of the present invention is to provide a communication device capable of QoS control and a communication system. A device 114 such as a first IP telephone having the QoS control unit 121 of the present invention transmits first transmission control data to a device 111 such as a PC performing low priority communication. The first transmission control data includes data for changing the communication path of the low priority communication, and the PC 111 that has received the first transmission control data subsequently performs the low priority communication via the device 114 such as the first IP telephone. Thus, the first QoS control unit 121 can perform priority control. Since the present invention uses a widely used protocol such as ARP or ICMP, the apparatus 111 that receives control data does not need to have a protocol specific to the present invention.

Description

  The present invention relates to a communication device capable of QoS control, a storage medium, an integrated circuit, and a communication system.

  In recent years, broadband Internet connections have been used in many workplaces and homes. FIG. 32 shows a typical Internet connection configuration in the current home. The user contracts with a first ISP (Internet Service Provider) 3 and installs the first router 12 purchased (or rented from the ISP) in the first home 1. Then, the first router 12 is connected to a device to be connected to the Internet 2 such as a PC (Personal Computer) 11.

  In this environment, when the PC 11 communicates with the server 13 disclosed on the Internet, the PC 11 passes through the first router 12, the access line 6, the first ISP 3, the Internet 2, and the like. Currently, ADSL lines (downstream: about 1 Mbps to 50 Mbps, upstream: about 512 Kbps to about 5 Mbps (see Non-Patent Document 1)) are widely used as access lines. Further, Ethernet (registered trademark) (bidirectional 100 Mbps) is generally used as a transmission medium in a home LAN. The first router 12 described herein may include an ADSL modem function on the Internet side and a hub function on the LAN (in-home) side as necessary. To do.

  In addition, applications that perform real-time communication using IP (Internet Protocol) used on the Internet, such as IP phones and IP videophones, have been widespread in recent years. For example, IP Centrex and IP telephone systems are used in companies, and IP telephones using broadband Internet connection such as ADSL and optical fiber are used in homes.

  However, since IP basically does not have a function for guaranteeing quality, when real-time communication is performed, if the communication band is not sufficient or is affected by other communication, the quality of service (QoS: Quality of Service) ) May be reduced.

  For example, when considering FIG. 33 as an example in which an IP telephone is simply connected to the environment shown in FIG. 32, there is a risk that QoS will decrease. Below, the mechanism is demonstrated.

  In FIG. 33, the first IP telephone 14 is connected to the LAN side of the first router 12. In this configuration, when communication is performed between the first IP telephone 14 and the second IP telephone 17 existing in another second home 4, the first router 12, the first ISP 3, the Internet 2, and the second home 4 side side are connected. 2 ISP 5 and the second router 16 are routed.

  Here, considering the case where the IP telephone communication 32 is performed simultaneously with the PC-server communication 31 in the environment as shown in FIG. 33, both communications go through the first router 12 and the first ISP 3. In the following, the processing of the first router 12 at this time will be described, and it will be described that the QoS of the IP phone is lowered due to a phenomenon occurring there.

  FIG. 34 schematically shows the detailed structure inside the first router 12 in FIG. 33 (particularly, only the part related to data transfer from the LAN side to the access line side). The configuration outside the first home 1 in FIG. 34 is the same as that in FIG.

  First, the operation when only the communication 32 between the IP phone and the IP phone exists will be described. First, the first IP telephone 14 sends voice data as an IP packet to the LAN line 7. Next, when receiving this packet, the first router 12 temporarily stores data in the reception buffer 21. Then, the transmission processing unit 22 processes the data at the head of the reception buffer 21 and sends it to the access line 6. The transmission amount of the voice data transmitted from the first IP telephone 14 is about 64 Kbps (in the case of ITU-T G.711), which is less than twice the protocol overhead in the lower layer. Therefore, since the ADSL uplink line speed (512 Kbps ~) is not reached, a large amount of data is not stored in the reception buffer 21, and the received data can be immediately sent to the access line 6. For this reason, QoS of IP telephone communication is ensured.

Next, consider the processing of the first router 12 when the communication 31 between the PC and the server 31 is simultaneously performed in addition to the communication 32 between the IP phone and the IP phone. For example, if the communication 31 between the PC and the server is file transfer, the PC 11 transmits a large amount of data to the LAN line 7 at a stroke in order to transfer the file as fast as possible. The transfer speed (100 Mbps) of the LAN line 7 is very high compared to the upstream line speed (up to about 5 Mbps) of ADSL. Therefore, a large amount of data is accumulated at once in the reception buffer 21 of the first router 12. The transmission processing unit 22 sends the data stored in the reception buffer 21 to the access line 6 in order from the data existing at the head. Under such circumstances, the following phenomena such as (Phenomenon 1) to (Phenomenon 3) occur. (Phenomenon 1) After the IP telephone communication data is stored in the reception buffer 21, the access line 6 The delay time until the data is sent to is increased.

  (Phenomenon 2) When data of IP telephone communication is stored in the reception buffer 21, how much data is stored in the reception buffer 21 differs depending on the timing, and as a result, delay time fluctuation (jitter) occurs.

  (Phenomenon 3) When the IP telephone communication data arrives at the first router 12, if the reception buffer 21 is not empty, the arrived IP telephone communication data is discarded and data loss occurs.

  If the above phenomenon occurs, the arrival of data will not be in time for the normal playback of audio on the receiving side, and the audio will be interrupted or the sound quality will deteriorate.

  Therefore, Non-Patent Document 2 discloses a home IP telephone service in a configuration that makes it possible to prevent a decrease in QoS of IP telephone communication due to the occurrence of the above phenomenon. FIG. 35 shows a configuration in which the analog telephone 70 and the dedicated router 60 are connected via the analog line 73 using the dedicated router 60 together with the function (such as the voice data conversion unit 22) as an IP telephone. In the case of such a configuration, the dedicated router 60 can improve the QoS of the IP phone by performing the following processing.

First, analog data from the analog telephone 70 is converted by the voice data converter 25 and used as voice data for IP telephone communication. Here, the file transfer data from the PC 11 is stored in the reception buffer 23, and the voice data for IP telephone communication converted by the voice data conversion unit 25 is stored in the voice data buffer 24. Next, when audio data is stored in the audio data buffer unit 24, the transmission processing unit 22 preferentially transmits the data to the access line 6 that is an ADSL uplink. On the other hand, the transmission processing unit 22 transmits the file transfer data stored in the reception buffer 23 to the access line 6 only when the audio data is not stored in the audio data buffer 24. In this way, the audio data is not waited for a long time in the audio data buffer 24, and the audio data is not lost. In this way, the QoS of IP telephone communication can be improved.

  However, even when the above control is performed, the QoS of IP telephone communication may be lowered due to the occurrence of phenomenon 4 below.

  (Phenomenon 4) When a voice data packet for IP telephone communication arrives at the voice data buffer 24 while the file transfer data is being transmitted to the access line, the voice data packet is transmitted until the file transfer data transmission is completed. Absent. As a result, audio data delay and delay fluctuation occur.

  Hereinafter, phenomenon 4 will be described in detail with reference to FIGS. 35 and 36. FIG. FIG. 36 is an explanatory diagram for explaining a data transmission period from the router. FIG. 36 illustrates the arrival timing of file transfer data to the router, the timing of voice data generation, and the transmission period of each data to the access line 6, and the horizontal axis represents time. First, consider a state in which audio data is not accumulated in the audio data buffer 24 and only file transfer data is accumulated in the reception buffer 23. This state occurs, for example, when the arrival of the file transfer data 2501 in FIG. 36 occurs in a state where there is no data in the respective buffers 23 and 24. According to the above control, first, file transfer data arriving at the buffer 23 first starts to be transmitted to the access line 6. As shown in FIG. 36, it is assumed that the first audio data 2502 is generated before the transmission of the file transfer data is completed. The first audio data remains stored in the audio data buffer 24 until the file transfer data is completely sent to the access line 6. Therefore, a waiting time 2511 for the first audio data occurs. This waiting time is a maximum value calculated by “time required for file transfer data transmission = file transfer data packet size (bit) / access line speed”. This waiting time causes delay time and delay time fluctuation (jitter), and lowers the QoS of IP telephone communication.

Since file transfer data is generally transferred using TCP (Transmission Control Protocol), the size is often about 1500 bytes per packet. For example, if the speed of the access line is 512 Kbps, the time taken to transmit one packet is about 23 milliseconds. Non-Patent Document 3 describes the IP telephone quality standards prescribed by the Ministry of Internal Affairs and Communications. Among them, the end-to-end delay is 100 milliseconds or less as a class A standard that calls quality is comparable to fixed telephones. Therefore, it can be said that the above-mentioned delay of 23 milliseconds leads to a decrease in QoS of IP telephone communication.

  In order to reduce the waiting time of voice communication data due to such phenomenon 4 and improve the QoS, for example, in Patent Document 1, a router device (transfers voice data and PC communication data to an external network such as the Internet). 35, which corresponds to the dedicated router 60 in FIG. 35) performs IP fragmentation (fragmentation) before transferring communication data from the PC to the access line. Thus, by fragmenting file transfer data, the packet size is reduced. Therefore, by interposing the audio data between the file transfer data and the file transfer data having a reduced packet size, the waiting time of the audio data can be reduced.

Patent Document 2 discloses a method for preliminarily securing network resources such as bandwidth before starting communication in order to realize QoS control of real-time communication such as IP telephone communication. As a result, it is possible to prevent the QoS degradation of the real-time communication due to the phenomenon 1 to the phenomenon 3. In Patent Document 2, each router that relays real-time communication has a bandwidth management table for managing the correspondence between each flow passing through the router and the bandwidth allocated to each flow, and bandwidth control is performed based on the bandwidth management table. I do. Here, each flow includes an arbitrary flow including real-time communication and non-real-time communication, and each flow is identified by the source address and destination address of the IP header. A separate server device for centrally managing the bandwidth management table of each router exists, and the server device sets the bandwidth management table of each router in response to a request from a communication device that performs real-time communication.
JP 2001-53805 A JP 2003-60691 A Service list of ADSL line provider e-access <http: // www. eacess. net / service / 47mir / index. html>, search date September 10, 2004 IP phone service Yahoo! Connection configuration diagram when using BB service <http: // bbpromo. yahoo. co. jp / promotion / service / bbphone / simple_guide. html>, search date September 10, 2004 Report on “Research Group on IP Network Technology” <http: // www. soumu. go. jp / s-news / 2002 / 020222_3. html>, search date January 13, 2005

  However, when the IP telephone service in Non-Patent Document 2 is used or the method described in Patent Document 1 is used to prevent QoS degradation, the output of the analog telephone 70 is input, It is necessary to control by a dedicated router having the fragment function described in 1, and the degree of freedom of the user is low due to the configuration of the installation of the dedicated router. Furthermore, in order to use the IP telephone service described in Non-Patent Document 2, it is necessary to subscribe to a specific ISP and purchase a dedicated router 60 or rent a monthly fee. Therefore, for users who have subscribed to an ISP that cannot use the IP phone service and used the Internet connection in the configuration shown in FIG. 32, in order to use the IP phone, the initial cost when switching the ISP and the replacement of the router There is a problem that costs are incurred. In addition, by switching ISPs, problems such as the inability to receive services provided only by ISPs that have been previously subscribed, such as hosting services and virus check services, and changes in e-mail addresses also occur.

  In order to apply the method for realizing the QoS control described in Patent Document 2, it is necessary to operate cooperatively as a system including routers on the Internet, routers in the home, and IP telephones. Therefore, it is impractical to make such a system change in order to use an IP telephone at home.

  Therefore, an object of the present invention is to provide a communication apparatus and a communication system capable of QoS control.

  In order to solve the above-described problem, claim 1 of the present application is one of communication apparatuses that perform communication via a network in which a plurality of communications with different priorities is performed, and communication that controls communication according to the priorities. A priority information holding means for holding priority information relating to the priority of each communication, and first control data for changing a communication path of low priority communication based on the priority information; And a path change control means for transmitting the first control data to a low priority communication apparatus that performs the low priority communication or a relay apparatus that relays the low priority communication performed between other communication apparatuses via the network. And a communication device characterized by comprising:

  A low-priority communication apparatus that performs low-priority communication is a first control for changing a communication path of low-priority communication from a communication apparatus that controls communication according to priority (hereinafter, communication apparatus that performs priority control). Data is received and the communication path is changed based on the first control data. Therefore, when high-priority communication and low-priority communication are congested, the high-priority communication path can be preferentially secured by changing the low-priority communication path. . As described above, the communication device that performs priority control can control communication according to the priority in addition to the communication function. Therefore, by connecting a communication device that performs the above-described priority control to a home LAN that does not perform communication control according to priority, communication is performed via the network using the communication device that performs priority control. However, QoS for high priority communication can be ensured. Therefore, in order to ensure QoS, it is not necessary to provide a separate dedicated router that controls communication according to priority. Therefore, the user does not need to change the existing router or system configuration, and can subscribe to an arbitrary provider and perform real-time communication such as an IP phone with high quality. Further, the QoS of the high-priority communication device can be changed without changing the entire system including the low-priority communication device, the high-priority communication device, and the relay device by simply providing a communication device that performs priority control capable of ensuring QoS. Can be secured.

  As a high-priority communication apparatus that performs high-priority communication, for example, an IP telephone or the like that requires real-time performance such as telephone communication can be cited. Moreover, as a low priority communication apparatus, the terminal etc. which perform a file transfer etc. are mentioned, for example. Therefore, real-time performance can be maintained by securing the QoS of the IP telephone using a communication device that performs priority control.

  In addition, when transmitting 1st control data to a low priority communication apparatus, the communication path from a low priority communication apparatus to the other party's communication apparatus can be changed. Further, when the first control data is transmitted to the relay device, the communication path from the counterpart communication device to the low priority communication device can be changed.

  A second invention of the present application is the communication according to the first invention, wherein the route change control means changes the destination of the communication route of the low priority communication to an untransmittable address in the first control data. Providing equipment.

  By changing the destination of the communication path of the low priority communication to an address that cannot be transmitted, the low priority communication device transmits the transmission data to an address that cannot be transmitted. Therefore, since transmission data transmitted from the low priority communication device is discarded, a communication path for performing high priority communication is established even when communication of high priority communication and communication of low priority communication are congested. Priority can be secured.

  A third invention of the present application is the communication device according to the first invention, wherein the path change control means controls communication of a destination of a communication path of the low priority communication included in the first control data according to the priority. The communication apparatus further includes communication control means for controlling the output of transmission data from the low priority communication apparatus to the network.

  By changing the destination of the communication path of the low priority communication to the communication device that performs the priority control, the transmission data from the low priority communication device is transmitted to the communication device that performs the priority control. Then, the communication device that performs priority control adjusts, for example, to limit the output of transmission data from the low priority communication device to the network. Thereby, even if the communication of high priority communication and the communication of low priority communication are congested, the communication path of high priority communication can be secured preferentially.

  According to a fourth invention of the present application, in the third invention, the communication control means determines whether or not the transmission destination of at least one received data is its own device, and the received data is low priority communication from the low priority device. Analyzing means for analyzing whether or not the data is high-priority communication data is preferentially selected over low-priority communication data whose destination is other than the own device according to the analysis result by the analyzing means. And a selecting means for controlling to transmit to the transmission destination.

  Note that it is possible to determine whether or not relaying is necessary based on whether or not the destination of the received data is its own device. By these analysis means and selection means, it is possible to preferentially secure a communication path for high priority communication even when high priority communication and low priority communication are congested.

  Here, it further includes a transmission data generation unit that generates transmission data to be transmitted to the counterpart communication device, and when the transmission data is high-priority communication data, the selection unit preferentially transmits the transmission data. select. Thus, when the communication device itself transmits high-priority transmission data to another communication device, it transmits the high-priority transmission data with priority over the low-priority communication data that needs to be relayed. be able to. In addition, the selection means selects so as to preferentially transmit high priority communication data from among a plurality of received data to be received. As a result, when the communication device receives a plurality of received data from a plurality of communication devices and needs to relay to another communication device, the received data with the highest priority among these received data is preferentially transmitted. can do.

  The fifth invention of the present application is the fourth invention, wherein, as a result of the analysis by the analyzing means, the communication control means sets the source address of low priority communication data whose destination is other than the own apparatus as the address of the own apparatus. The adjusting unit further includes an adjusting unit that performs an address rewriting process for rewriting the destination address of the low priority communication data to the original destination address of the low priority communication data transmitted from the low priority communication device before the path change. Provides a low-priority communication data after the address rewriting process to the selection means.

  It operates as a network device that performs relay and loopback by rewriting the address, and can appropriately relay and loopback traffic.

  A sixth invention of the present application further includes an upper layer processing unit for processing received data whose destination is the own apparatus as a result of analysis by the analyzing means in the fourth invention, wherein the analyzing means has a destination of the received data Whether the device is the device itself is determined by analyzing the IP header of the received data based on whether the destination is the IP address of the device itself. If the destination of the received data is the device itself, the higher layer processing unit The communication apparatus according to claim 4, wherein the reception data is transmitted to the selection unit and the reception data is transmitted to the selection unit when the destination is other than the own apparatus.

  Relay and loopback can be performed by analyzing at the IP level a frame that is to be detoured at the Ethernet (registered trademark) level. In addition, since the priority control device does not perform any processing including interrupt processing for frames addressed to other devices, it eliminates the need for extra processing related to communication.

  A seventh invention of the present application provides the communication device according to the third invention, wherein the communication control means is realized by hardware.

  Processing for relaying frames addressed to other devices and processing related to priority control can be performed by hardware, and priority control is performed without using an expensive CPU as long as the CPU is capable of transmitting and receiving the local terminal application. be able to.

  According to an eighth invention of the present application, in the fourth invention, the communication control means further includes an adjustment means for discarding a part or all of the low priority communication data, and the adjustment means is partially or entirely discarded. The communication apparatus is characterized in that the low priority communication data is transmitted to the selection means.

  Even if the communication means of the communication device that performs priority control discards the transmission data from the low-priority communication device, the communication of the high-priority communication and the communication of the low-priority communication are congested. A communication path for performing communication every time can be preferentially secured.

  The ninth invention of the present application is the fourth invention, wherein the communication control means further includes an adjustment means for performing a first adjustment process for adjusting a communication rate of the low-priority communication. A communication apparatus is provided, wherein low-priority communication data after one adjustment process is transmitted to the selection means.

  By adjusting the transmission rate of the transmission data received from the low-priority communication device, the transmission rate from the counterpart communication device of the low-priority communication device and the transmission rate from the counterpart to the low-priority communication device are adjusted. be able to. Therefore, when high-priority communication and low-priority communication communication are congested, the amount of transmission from the low-priority communication device to the partner or the destination can be reduced by adjusting the transmission rate to be lower. It is possible to reduce the amount of transmission from the priority communication device and preferentially secure a communication path for performing high priority communication.

  A tenth invention of the present application provides the communication apparatus according to the ninth invention, wherein the adjusting means adjusts a transmission rate by adjusting a value of a window field of a TCP header.

  By adjusting the TCP flow control of the low priority communication device, it is possible to preferentially secure a communication path for performing high priority communication.

  The eleventh invention of the present application is the ninth invention, further comprising storage means for storing the low priority communication data, wherein the adjustment means is configured such that the low priority communication data is a TCP data packet or a TCP ACK packet. In such a case, the communication apparatus is characterized in that the low-priority communication data is accumulated for a certain period of time using the accumulating unit and then transferred to the selecting unit.

  By adjusting the TCP flow control of the low priority communication device, it is possible to preferentially secure a communication path for performing high priority communication.

  The twelfth invention of the present application is the fourth invention, wherein the communication control means further comprises an adjusting means for dividing the transmission data from the low priority communication device into a plurality of data using a first dividing method, The adjustment unit provides a communication apparatus, wherein the data divided into a plurality of pieces using the first division method is transmitted to the selection unit.

  The adjustment means of the communication device that performs the priority control divides the transmission data from the low priority communication device so that the data of the high priority communication that arrives during the data transfer of the low priority communication is waited for a long time. Can be prevented. Therefore, QoS of high priority communication can be improved.

  A thirteenth invention of the present application provides the communication apparatus according to the twelfth invention, wherein the first dividing method divides into IP fragments.

  Since the IP fragment reception function is a function that a normal IP communication apparatus has, it is possible to improve the QoS of high priority communication without requiring a special function from another apparatus.

  In a fourteenth aspect of the present invention, in the fourth aspect, the communication control means communicates with the other party of the low priority communication device from the low priority communication device based on communication data received from the low priority communication device. Generating the third control data for controlling the size of the communication data to the device or the communication data from the communication device of the counterpart of the low priority communication device to the low priority communication device, and the low priority communication There is further provided a communication device further comprising adjusting means for transmitting to the device or the communication device of the other party.

  The adjusting means controls the size of communication data from the low priority communication device to the counterpart communication device based on communication data received from the counterpart communication device of the low priority communication device. Fourth control data may be generated and transmitted to the low priority communication device.

  In this way, by adjusting the transmission rate from the low-priority communication device to the counterpart communication device and the transmission data size from the counterpart to the low-priority communication device, the data transmission of low-priority communication is being performed in the communication device. Therefore, it is possible to prevent the data of high priority communication arriving at the terminal from waiting for a long time, and to improve the QoS of high priority communication.

  In a fifteenth aspect of the present invention, in the fourteenth aspect, the third control data is a TCP SYN packet, and the adjustment unit generates a SYN packet in which the MSS value included in the received SYN packet is changed to a desired value. A communication device is provided.

  The size of transmission data can be reduced by changing the MSS value. Such an MSS adjustment function by the MSS option in the SYN packet is a function that a normal IP communication apparatus has. Therefore, QoS of high priority communication can be improved without requiring a special function from another device.

  According to a sixteenth aspect of the present invention, in the fourteenth aspect, the third control data is an ICMP destination unreachable fragmented packet, and the adjusting means includes data included in a packet transmitted from a low-priority communication device before An ICMP destination unreachable fragmentation packet including a part of the packet and including a desired MTU value is generated.

  The low-priority communication device that has received the destination unreachable fragmented packet determines the subsequent packet size based on the MTU value included in the received packet. By changing the MTU value of the low-priority communication device by the adjusting means of the high-priority communication device, the size of the transmission data from the low-priority communication device can be reduced. Since the MTU adjustment function when such an ICMP destination unreachable fragmented packet is received is a function that a normal IP communication device has, it has high priority without requiring a special function from other devices. Can be improved.

  A seventeenth invention of the present application is the first invention, wherein the route change control means changes a destination of the communication route of the low priority communication to the address of the own device in the first control data, and the priority Generating second control data for changing the communication path of the high priority communication based on the information, and changing the destination of the communication path of the high priority communication in the second control data to the address of the own device The communication apparatus is characterized in that the second control data is transmitted to the high priority communication apparatus.

  A communication device that performs priority control can accurately grasp the congestion state of high-priority communication and low-priority communication by receiving communication from not only low-priority communication devices but also high-priority communication devices. . Then, based on the grasped congestion state and priority information, when there is congestion, the data from the high priority communication device is output to the network with priority over the data from the low priority communication device. Therefore, a communication path for high priority communication can be secured with priority.

  In an eighteenth aspect of the present invention, in the first aspect, the first control data transmitted by the path change control means is any one of an ARP request packet, an ARP response packet, an ICMP path change packet, and an ICMPv6 neighbor search packet. A communication device is provided.

  The mechanism of the ARP request and the ARP response is implemented in almost many IP-compatible devices. Therefore, the first control data for changing the communication path of the low priority communication can be generated using the existing ARP request and ARP response. Similarly, the ICMP path change mechanism is also implemented in almost all IP-compatible devices. Also, the mechanism of ICMPv6 neighbor discovery packet is implemented in many IPv6 devices. Therefore, when the communication of high priority communication and communication of low priority communication are congested using the existing mechanism, the communication path of high priority communication can be secured with priority.

  The nineteenth invention of the present application further includes detection means for detecting whether or not communication via the network by the high priority communication device is performed in the first invention, wherein the route change control means is the high priority communication. Provided is a communication device characterized in that the first control data is transmitted to the low priority communication device or the relay device only when communication is performed by the device.

  By changing the communication path for low-priority communication according to the presence or absence of high-priority communication, the communication path for high-priority communication can be secured only during the required period, and to low-priority communication during other periods The influence of can be eliminated.

  The twentieth invention of the present application further comprises a QoS value holding means for holding a QoS value set to hold the quality of high priority communication in the nineteenth invention, wherein the detection means further A value indicating quality is calculated, the calculated quality value is compared with the QoS value, and when the calculated quality value is smaller than the QoS value, the path change control means includes: The communication apparatus is characterized in that the first control data is transmitted to the low priority communication apparatus or the relay apparatus.

  By changing the communication path for low-priority communication according to the deterioration of the quality of high-priority communication, it is possible to secure the communication path for high-priority communication only during the required period, and low priority during other periods. The influence on communication can be eliminated.

  A twenty-first invention of the present application is a computer-readable recording medium on which a priority control program executed by a control device that controls communication according to the priority is recorded in a plurality of communications performed via a network. And priority information holding means for holding priority information related to the priority of each communication, and based on the priority information, generate first control data for changing the communication path of the low priority communication, A computer as a path change control means for transmitting the first control data to a low-priority communication device that performs the low-priority communication or a relay device that relays low-priority communication performed between other communication devices via the network A computer-readable recording medium is provided, in which a priority control program for functioning is recorded. By using the recording medium in which the priority control program is described, the same function and effect as the first invention of the present application are obtained.

  The 22nd invention of the present application is an integrated circuit that controls communication according to the priority in a network in which a plurality of communications with different priorities are performed, and priority information that holds priority information about the priority of each communication Based on the holding means and the priority information, the first control data for changing the communication path of the low priority communication is generated, and the low priority communication apparatus or the network that performs the low priority communication is used. There is provided an integrated circuit comprising: path change control means for transmitting the first control data to a relay apparatus that relays low priority communication performed between other communication apparatuses. The integrated circuit has the same effects as the first invention of the present application.

  A twenty-third invention of the present application is a communication device that controls communication according to priority in a communication system in which a communication device that controls communication according to communication priority and a plurality of communication devices with different priorities are connected. Includes priority information holding means for holding priority information related to the priority of each communication, and first control data for changing a communication path of low priority communication with low priority based on the priority information. Route change control for generating and transmitting the first control data to a low priority communication device that performs the low priority communication or a relay device that relays low priority communication performed between other communication devices via the network A low-priority communication device or a relay device that relays low-priority communication performed between other communication devices via the network, the communication device controlling communication according to the priority Receive al the first control data, and changes the communication path of the low-priority communication, to provide a communication system. The said communication system has the same effect as 1st invention of this application.

  According to the present invention, by changing the communication path of low-priority communication, it is possible to perform control to give priority to high-priority communication that requires high QoS, such as real-time communication, and to ensure the communication quality. .

The network block diagram in 1st Embodiment. The block diagram of the QoS control part and 1st IP telephone in 1st Embodiment. Data format of ARP request / ARP response. The flow of data in the QoS control procedure when using an ARP request. Process and data flow in QoS control procedure when ARP request is used. The QoS control processing flow in a path | route change control part at the time of using an ARP request | requirement. ARP table (1) of the device to be controlled. The ARP table (2) of the device to be controlled. ARP table (3) of the device to be controlled. IP address and MAC address list of each device. The installation position of the communication apparatus of this invention, and the flow of communication after path | route change control in case the communication apparatus of this invention is an independent LAN terminal. QoS control device. Neighbor solicitation packet and neighbor notification packet format. Format of ICMP route change packet. The flow of data in the QoS control procedure when an ICMP path change packet is used. Process and data flow in QoS control procedure when ICMP path change packet is used. The routing table (1) of a control object apparatus. The routing table (2) of a control object apparatus. The network block diagram in 2nd Embodiment. The block diagram of the QoS control part and IP telephone in 2nd Embodiment. Processing and data flow when performing detailed control after route change control. ARP table of the control target device. The routing table of the control target device. Ethernet (registered trademark) frame and IP packet format. The flowchart of the reception process in a low priority communication packet relay process. The flowchart of the transmission process in a low priority communication packet relay process. Detailed operation in packet relay processing (when full-duplex, with buffer). Detailed operation in packet relay processing (when full-duplex, no buffer). Detailed operation in packet relay processing (in case of half duplex). Processing and data flow when performing IP fragmentation in detailed control after route change control. TCP SYN packet format with MSS option. Processing and data flow when changing MSS value of TCP SYN packet in detailed control after route change control. ICMP destination unreachable fragmented packet format. Processing and data flow when ICMP destination unreachable fragmented packet is transmitted in detailed control after route change control. The block diagram of the network of the current home LAN (without IP phone). The network block diagram at the time of adding an IP telephone to the network of FIG. The internal structure figure of the router of FIG. The network block diagram in a prior art example, and the internal structure of a router. Explanatory drawing of the phenomenon in which term priority communication data is waited when the packet size of low priority communication is large.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a network configuration diagram according to the first embodiment. In FIG. 1, communication devices such as a PC 111 and a first IP telephone 114 are connected to the LAN side of a first router 112 existing in the first home 101 to form a home LAN. The home LAN is connected to the Internet 102 via the access line 106 and the first ISP 103. The second router 116 is also present in another second home 104, and a second IP telephone 117 is connected to the LAN side. The home LAN of the second home 104 is connected to the Internet 102 via the second ISP 105.

  In FIG. 1, file transfer 131 (hereinafter referred to as PC-server communication 131) is transferred between the PC 111 in the first home 101 and the server 113 on the Internet 102, and the first IP telephone 114 in the first home 101. IP telephone communication 132 (hereinafter referred to as IP telephone-IP telephone communication 132) using the Internet 102 is performed with the second IP telephone 117 in the second home 104. Here, the communication 132 between the IP phone and the IP phone is a communication that requires real-time property, and is a high priority communication with a high priority. On the other hand, the communication 131 between the PC and the server is a low priority communication with a low priority. The first IP telephone 114 is a high priority communication device, and the PC 111 is a low priority communication device.

  In FIG. 1, a QoS control unit 621 is provided as a function unit of the first IP telephone 114, and QoS is controlled by the QoS control unit 621.

  Further, the internal configuration of the first IP telephone 114 and the QoS control unit 621 in FIG. 1 will be described in more detail with reference to FIG. FIG. 2 is an internal configuration diagram in the first IP telephone 114 and the QoS control unit 621. As shown in FIG. 2, the QoS control unit 621 includes a priority information holding unit 841 and a path change control unit 842. The priority information holding unit 841 holds priority information related to communication priority. The priority information is information for distinguishing which communication is a communication with a high priority. The route change control unit 842 generates route change control data for changing the communication route of the low priority communication, and is performed between the other communication devices via the PC 111 or the network that performs the low priority communication. The route change control data is transmitted to a relay device that relays communication. Further, the route change control unit 842 can receive data from the LAN line 107 and transmit data to the LAN line 107 via the communication processing unit 123 in the first IP telephone 114. The IP telephone application 122 in the first IP telephone 114 receives voice input from the user, generates voice data for IP telephone communication, and connects the LAN line 107 via the TCP / IP processing unit 124 and the communication processing unit 123. To send to.

  Hereinafter, the first IP telephone 114, which is the communication apparatus of the first embodiment, interrupts the low priority communication by changing the path of the low priority communication (PC-server communication 131 in FIG. 1), A procedure for securing QoS for priority communication (IP telephone-IP telephone communication 132 in FIG. 1) will be described.

  First, the outline of the QoS control process will be described by explaining the overall flow of the QoS control process, and then the detailed procedure of the QoS control process will be explained.

<Overall flow of QoS control processing>
The QoS control process in the first embodiment of the present invention is roughly performed in the following procedure.

  First, as a state before the QoS control process is performed, it is assumed that only low priority communication (PC-server communication 131) is performed in the network of FIG. Thereafter, when high-priority communication (IP telephone-IP telephone communication 132) is started, the QoS control unit 621 performs the following control. Hereinafter, a description will be given with reference to FIG.

(1) Procedure 1
The priority information holding unit 841 holds priority information for distinguishing between low priority communication and high priority communication, and notifies this to the route change control unit 842 (S851). Here, the first IP telephone 114 is set as a high priority communication apparatus that performs high priority communication, and the PC 111 is set as a low priority communication apparatus that performs low priority communication.

(2) Procedure 2
The route change control unit 842 obtains information such as an IP address necessary for generating route change control data for route change (S852). Note that information acquired by the route change control unit 842 differs depending on the route change method.

  The route change control unit 842 generates route change control data for route change from the information acquired here and the information obtained by the procedure 1, and terminates low priority communication that is a device to be controlled for route change. The route change control data is transmitted to the PC 111 (S853).

  The communication processing unit 123 sends this route change control data to the LAN line 107. The route change control data includes information on the destination after the change of the data output from the PC 111 which is a low priority communication device. In this embodiment, an address that does not exist in the LAN, such as an IP address or a MAC address, is designated as the destination after the change.

(3) Procedure 3
The PC 111 that is a low-priority communication device and a device to be controlled receives the route change control data, and changes the communication route of subsequent low-priority communication data.

(4) Procedure 4
When the communication path is changed according to the procedure 3, the PC 111 transmits data to an address that does not exist. Thereby, the low priority communication is interrupted until the communication path returns to the original state by some processing. That is, data from the PC 111 generated in the PC-server communication 131 that is low priority communication is transmitted to other than the first router 112, and the low priority communication is interrupted. Therefore, the first router 112 receives only the voice data from the first IP telephone 114 generated in the communication 132 between the IP telephone and the IP telephone, which is high priority communication. Therefore, the first router 112 is not congested with high priority communication and low priority communication. In this way, when high-priority communication and low-priority communication are congested, the communication path for low-priority communication is changed to preferentially secure the communication path for high-priority communication. QoS can be secured. By connecting a communication device having such a QoS control processing function to a home LAN or the like where communication control according to priority is not performed, a network is configured using the communication device having the QoS control function. The QoS of the high priority communication can be ensured while performing the communication via the network. Therefore, in order to ensure QoS, it is not necessary to provide a separate dedicated router for controlling communication according to priority. Therefore, the user does not need to change the existing router or system configuration, and can subscribe to an arbitrary provider and perform real-time communication such as an IP phone with high quality. Further, by providing only the first IP telephone 114 capable of ensuring QoS, QoS of high priority communication can be ensured without changing the entire system including the PC 111 and the router which are low priority communication devices.

  Note that low-priority communication does not necessarily have to be started before the execution of this procedure. Even if low-priority communication is started after the start of high-priority communication, low-priority communication is not It is interrupted and QoS of high priority communication can be secured.

<Detailed procedure of QoS control process>
Next, a detailed procedure when the above procedure is performed will be described below for Procedure 1 to Procedure 4 in <Overall Flow of QoS Control Processing>. Although there are several methods for changing the route, it is assumed here that an ARP request (request) is used. This method can be used only when the communication processing unit 123 operates according to the Ethernet (registered trademark) protocol.

  First, ARP (Address Resolution Protocol) will be described in order to understand the procedure described below. ARP is a protocol for notifying each other between devices communicating within a LAN about the correspondence between IP addresses and MAC addresses (addresses unique to network I / F hardware) in Ethernet (registered trademark). When performing IP communication over Ethernet (registered trademark), each device normally sends an ARP request (specifying the IP address of the communication partner) as a broadcast Ethernet (registered trademark) frame once every five minutes and receives it. When the designated IP address is its own, each device returns an ARP response as a unicast Ethernet (registered trademark) frame.

  FIG. 3 is a protocol format of an ARP request and an ARP response defined in RFC826. The field 911 does not show details here, but includes various fields such as a field indicating whether this data is an ARP request or an ARP response. Further, the ARP request and the ARP response include a source MAC address 912 and a source IP address 913 related to the source communication device, and information of a destination MAC address 914 and a destination IP address 915 related to the destination communication device. ing. Therefore, by receiving the ARP request or the ARP response, it is possible to know the MAC address for each other's IP address. The correspondence relationship between the IP address and the MAC address exchanged by communicating with each other is managed in the ARP table possessed by each communication device. Then, at the time of packet transmission, each communication device searches the ARP table using the destination IP address of the packet to be transmitted as a key, and determines the destination MAC address of the frame to be transmitted. Note that FCS (Frame Check Sequence) 916 is information added to check whether the Ethernet (registered trademark) frame is damaged.

  Hereinafter, the detailed procedure of the QoS control process when the ARP request is used will be described with reference to FIGS. 1 to 8 for each of the above (1) Procedure 1 to (4) Procedure 4. FIG. 4 is a schematic diagram showing the overall flow of data in the QoS control process when an ARP request is used, and shows how each piece of data 1061, 1062, and 1063 to be exchanged moves on the network. ing. FIG. 5 is an example of the overall process and data flow in the QoS control process when an ARP request is used. The time series of each data exchange in the QoS control process and the path change control data generation process in the first IP telephone 114 is shown. Show. FIG. 6 is an example of a route change control data generation process in the route change control unit when an ARP request is used, and FIGS. 7A to 7C are examples of the ARP table 1021 of the PC 11 that is the control target device. A state in which the ARP table 1021 is updated as needed. FIG. 8 is a list of IP addresses and MAC addresses of each device. The MAC addresses and IP addresses of the PC 111, the first router 112, the server 113, and the first IP telephone 114 are shown, and addresses that do not exist in the LAN are also fictitious. Defined as the address of the device 115.

(1) Procedure 1
The procedure 1 will be described with reference to FIG. First, in the present embodiment, the IP telephone communication performed by the first IP telephone 114 which is its own apparatus is a high priority communication, and all the communication from the LAN to the Internet 2 via the first router 112 is a low priority communication. Assuming communication, the QoS control unit 621 of the present invention operates. At this time, the priority information holding unit 841 in FIG. 2 has the IP_router value necessary for route change control by the ARP request as default information. Here, the IP_router is an IP address of the first router 112 that relays communication from the PC 111 and the first IP telephone 114 to the network 2 as shown in FIG. Note that this information is not predetermined information, and may be input from a user interface, or may be acquired by some procedure using a network.

  Next, the priority information holding unit 841 notifies the IP_router to the route change control unit 842 as information related to low priority communication (see S851 in FIG. 2). At the same time, in step S1302, which will be described later, IP_PC may be notified in order to check the IP address of the PC 111.

(2) Procedure 2
The procedure 2 and subsequent steps will be described with reference to FIGS.

  Step S1201: Next, the PC 111, which is a device in the LAN that terminates the low-priority communication, uses the IP address of the first router 112 that first passes to communicate with the server 113 as shown in S1201 of FIG. A broadcast ARP request 1061 is transmitted with a certain IP_router as the destination IP address 915. At this time, the ARP table of the PC 111 is the table 1171 of FIG. 7A.

  Thereafter, the route change control unit 842 in the QoS control unit performs the route change control data generation process in S1202. Details of this processing will be described with reference to the flowchart of FIG. 6, the data 1061 and 1062 of FIG. 5, and the block diagram of FIG. Further, the ARP request / response fields are as shown in FIG.

(Processing in S1202)
Step S1301: First, the route change control unit 842 receives the ARP request 1061 (1061 in FIG. 5) from the PC 111 via the communication processing unit 123, as shown in S1301 in FIG. Thereby, the input information for the route change process in S852 of FIG. 2 is received.

  Step S1302: Next, the path change control unit 842 checks whether the transmission source IP address of the ARP request 1061 received from the PC 111 is the IP address of the control target device. Here, since the first IP telephone 114 is a high priority communication apparatus and the communication apparatus that performs communication via the first router 112 other than the first IP telephone 114 is a low priority communication apparatus, the source IP address Check whether it is other than IP_router. Since the transmission source IP address 913 of the PC 111 which is the transmission source of the ARP request 1061 is IP_PC as shown in FIG. 8, this condition is satisfied.

  Steps S1303 to S1305: Next, the path change control unit 842 checks whether the destination IP address 915 of the ARP request 1061 from the PC 111 is an IP_router (S1303). Since the destination IP address 915 of the ARP request 1061 is an IP_router, it waits for a certain time (S1304). Thereafter, the route change control unit 842 generates route change control data, which is the unicast ARP request 1062 shown in FIG. 5, and transmits the route change control data to the PC 111 that is the control target device via the communication processing unit 123 (S1305). The destination IP address 915 and the source address 913 specified here are obtained by replacing the destination IP address 915 and the source IP address 913 of the received ARP request 1061. Further, the MAC_None that is the MAC address of the fictitious device 115 shown in FIG. 4 is set as the source MAC address 912. Here, the MAC address of the fictitious device 115 is an arbitrary MAC address different from the MAC address of the device existing in the LAN.

  Steps S1203 and S1204: Processing other than the route change control data generation processing (S1202) will be described again using FIG. While waiting for a certain period of time in the first IP telephone 114 in the route change control data generation process (S1202), the first router 112 transmits a normal ARP response 1063 to the received ARP request 1061 (S1203). Upon receiving this, the ARP table of the PC 111 is updated as shown in the table 1172 of FIG. 7B (S1207).

  Although not shown in the figure, when the route change control unit 842 receives a broadcast ARP request from a device other than the control coping device, for example, the first router 112, the route change control data generation processing (S1202) In step S1302, it is checked that the source IP address is not a control target device (S1302). However, the priority information holding unit 841 needs to notify the route change control unit 842 of the IP address of the device to be controlled in advance. In this case, since the route change control unit 842 of the first IP telephone 114 does not generate any route change control data and does not return any response, the route of data transmitted from the first router 112 is not changed. Absent.

(3) Procedure 3
Step S1205: The PC 111 that is the control target device that has received the path change control data 1062 updates the APR table based on the path change control data 1062 (S1205). The state of the APR table at this time is as shown in a table 1173 of FIG. 7C, and MAC_None that is a MAC address not existing in the LAN is registered as a MAC address corresponding to the IP_router.

  Note that the reason for performing the process of waiting for a certain time (S1304 in FIG. 6) is that if this process is not performed, the data arrives in the order of the path change control data 1062 and the ARP response 1063 from the router in the PC 111. This is because the ARP table 1021 finally becomes the table 1172 in FIG. 7B, and as a result, there is a possibility that the route cannot be changed.

(4) Procedure 4
Step S1206: As a result, the ARP table 1021 of the PC 111 becomes like the table 1173 of FIG. Thereafter, when the PC 111 attempts to transmit low priority communication data, it transmits communication data 1064 (see FIG. 4) destined for MAC_None (the MAC address of the fictitious device 115). Here, since the imaginary device 115 does not actually exist, the communication data 1064 is discarded without being received by any device. Therefore, after the route change, the communication 131 between the PC and the server, which is low priority communication, is interrupted.

  The return control data can also be transmitted as the route change control data 1062 that restores the ARP table of the PC 111 that is the control target device. At this time, in the return control data, the transmission source MAC address is changed to MAC_router. In this case, the MAC_router is also required as information regarding low priority communication that the priority information holding unit 841 notifies the route change control unit 842 in S851 of the procedure 1. Further, when the PC 111 as the control target device transmits an ARP request by broadcast again, the interrupted low priority communication can be resumed by a method of not transmitting the route change control data.

  Furthermore, it is possible to adjust the communication amount of low priority communication by adjusting the interval between interruption and resumption. For example, if low-priority communication in the PC 111 is performed by TCP, the transmission rate of low-priority communication gradually increases due to TCP flow control when restarting after interruption, and congestion occurs again after a certain time. Therefore, it is possible to control the transmission rate such that the time until congestion occurs again is measured dynamically and the next time is interrupted again at the timing immediately before the occurrence of congestion. When the interruption and restart processes are repeated a plurality of times, the procedure 3 may be omitted for the second and subsequent times.

  Further, when the high priority communication is completed, the ARP table of the PC 111 that is the control target device is restored to the original by the above method, so that after the high priority communication is completed, the communication path before the route change is restored. It is also possible to continue the communication 131 between the PC and the server, which is communication.

  If the transfer speed of the access line 106, which is a line in which congestion occurs, is known, it is determined at what interval the interruption and resumption should be performed in order to secure the QoS of high priority communication. You can also At this time, the relational expression between the transfer speed of the access line 106 and the interval of interruption / resumption can be obtained by conducting an experiment, for example.

  It is also possible to use a broadcast ARP request as the route change control data 1062. However, in this case, there is a possibility that another host that has received the ARP request determines that there are a plurality of communication devices having the same IP address, and communication cannot be continued normally. Further, the ARP response 1063 can be used as the route change control data 1062. However, in some implementations, when the control target apparatus receives the ARP response 1063 after transmitting the ARP request 1062, it does not receive another ARP response for a certain period of time, that is, the former becomes effective when a plurality of ARP responses arrive. Further, there is an implementation in which the ARP response 1063 is always accepted, that is, the latter becomes effective when a plurality of ARP responses arrive. Therefore, the route change control unit 842 of the present invention transmits a plurality of ARP requests, that is, route change control data 1062 so that it arrives both before and after the arrival of the ARP response 1063 to which the first router 112 responds. May be necessary.

  Further, here, a case has been described in which the control target device is the PC 111 that is a device that terminates low priority communication, that is, a case where the uplink communication path of the access line 106 is changed. However, even when the control target device is the first router 112 which is a device that relays low priority communication, that is, when the downstream route of the access line 106 is changed, it can be carried out by substantially the same procedure. That is, when determining whether or not the transmission source IP address is the control target device in S1302 of FIG. 6, control is performed when the transmission source IP address is the IP address of the first router 112. Then, instead of determining whether or not the destination IP address is the first router 112 in S1303 of FIG. 6, control may be performed when the destination IP address is not the first router 112. That is, the destination IP address is the IP address of another communication terminal that is not the first router 112. In this way, by changing the downstream path, for example, when flow control is performed like TCP, the data packet does not arrive at the PC 111, the PC 111 does not transmit an ACK packet to the server, and the server Since the ACK packet cannot be received from the server, the server cannot transmit a new packet. Therefore, the data transmission rate from the server to the PC 111 can be lowered. Further, when both the device that terminates the low priority communication and the relay device are set as control target devices, the route change control data may be transmitted without performing S1302 and S1303.

  With the above configuration, the following operational effects can be obtained in the first embodiment. When a communication device that performs priority control generates and transmits path change control data and communication between high priority communication and low priority communication is congested, the communication path of low priority communication is changed. Accordingly, a communication path for high priority communication can be secured with priority. As described above, the communication device that performs priority control can control communication according to the priority in addition to the communication function. Therefore, by connecting a communication device that performs the above-described priority control to a home LAN that does not perform communication control according to priority, communication is performed via the network using the communication device that performs priority control. However, QoS for high priority communication can be ensured. Therefore, in order to ensure QoS, it is not necessary to provide a separate dedicated router that controls communication according to priority. Therefore, the user does not need to change the existing router or system configuration, and can subscribe to an arbitrary provider and perform real-time communication such as an IP phone with high quality. Further, the QoS of the high-priority communication device can be changed without changing the entire system including the low-priority communication device, the high-priority communication device, and the relay device by simply providing a communication device that performs priority control capable of ensuring QoS. Can be secured.

  As a high-priority communication apparatus that performs high-priority communication, for example, an IP telephone or the like that requires real-time performance such as telephone communication can be cited. Moreover, as a low priority communication apparatus, the terminal etc. which perform a file transfer etc. are mentioned, for example. Therefore, real-time performance can be maintained by securing the QoS of the IP telephone using a communication device that performs priority control.

  In addition, when transmitting 1st control data to a low priority communication apparatus, the communication path from a low priority communication apparatus to the other party's communication apparatus can be changed. Further, when the first control data is transmitted to the relay device, the communication path from the counterpart communication device to the low priority communication device can be changed.

  Hereinafter, supplementary items regarding the present embodiment will be described in each section (<Applied environment>, <Installation position>, <Route change method>, and <Route change timing>).

<Applicable environment>
Up to this point, the example of the environment to which the first IP telephone 114 having the QoS control unit 621 of the present invention can be applied has been described using the network configuration of FIG. 1, but the present invention can be applied to a more general network configuration. It is.

  Before describing what kind of network configuration is applicable, here is a brief summary of the procedure by which the QoS problem that occurs in the configuration of FIG. 1 occurs.

  Generation procedure IP phone-IP phone communication 132 between the first IP telephone 114 in the first home 101 and the second IP telephone 117 in the second home 104, and between the PC and server between the PC 111 and the server 113. Communication 131 is performed simultaneously.

  Generation procedure The access line 106 is slower than the LAN line 107, and the first router 112 serving as a relay point competes for communication and congestion occurs.

  Generation procedure 3. Since priority control is not performed in the first router 112, the QoS of IP telephone communication decreases.

  In general, the above situation can be paraphrased as follows.

  Generation procedure High priority communication and low priority communication are performed simultaneously.

  Generation procedure Congestion occurs in a device that relays from a high-speed line to a low-speed line.

  Generation procedure 3. Since priority control is not performed in the relay device, the QoS of high priority communication decreases.

  The present invention is generally applicable in such a situation. That is, in the above, an IP telephone is taken as an example of a communication apparatus having the QoS control unit 621 of the present invention, but the communication apparatus is not limited to a PC, a server, or an IP telephone, and may be a DVD recorder, an IP video telephone, or the like. . The low-speed line need not be limited to the ADSL uplink line, and may be a wireless LAN line or a light line. Further, the present invention is not limited to an environment connected to the Internet, and can be applied to a case where a plurality of communications are simultaneously performed in a network environment closed to a home LAN, a corporate LAN, a regional IP network, or the like.

<Installation position>
Further, the present invention has been described as being implemented as the QoS control unit 621 in the first IP telephone 114 in FIG. 1, but it may be installed at other positions as shown in FIG. 9, the first IP telephone 114 having the QoS control unit 621 of the present invention and the QoS control units 1581 to 1585 having the functions thereof are arranged at various positions in FIG. Since the network configuration is the same as that in FIG.

  As shown in FIG. 9, the QoS control unit 621 can be installed independently of the IP telephone as long as it is connected to the home LAN. That is, the QoS control device 1583 having the above-described QoS control unit 621 may be provided as one terminal connected to the LAN side of the first router 112. The QoS control device 1583 is a single device having only the QoS control unit 621 as a functional unit as shown in FIG. Further, the QoS control devices 1585 and 1582 may be connected between the devices 111 and 114 connected to the first router 112 and the first router 112. However, when connecting between the first router 112 and the other devices 111 and 114, the QoS control devices 1585 and 1582 are bridges that relay communication between the first router 112 and the other devices 111 and 114, It operates as a repeater in the data link layer, which is the second layer.

  1 shows an example in which QoS control processing is implemented as the QoS control unit 621 in the first IP telephone 114, but a similar QoS control unit is installed in the PC 111 or the first router 112 as shown in FIG. 1584 and 1581 may exist.

  In some cases, the first IP telephone 114 having the QoS control unit 621 of the present invention is installed in a place other than the home LAN, and the effect is exhibited. Will be described in the description of the case where the route change control data is a DNS reply packet).

<Route change method>
So far, the procedure in the case of using the ARP request / ARP response as the procedure 1 to procedure 4 of <the overall flow of QoS control processing> has been described. However, as another method, an ICMPv6 neighbor discovery packet is used. There are a method, a method using an ICMP route change (redirect) packet or an ICMPv6 route change (redirect) packet, a method using a DNS reply packet, a method using a DHCP or DHCPv6 packet, a method of installing software on a PC, and the like. The procedure when these are used will be described below. However, the route changing method used in the present invention is not limited to these, and any method may be used.

[When using ICMPv6 neighbor search packet]
Here, a procedure when an ICMPv6 neighbor search packet is used as route change control data for route change will be described.

  First, the function of the ICMPv6 neighbor search packet will be briefly described. Neighbor Discovery in IPv6 (Internet Protocol Version 6) is defined in RFC 2461, and basically provides the same functions as ARP in IPv4 (Internet Protocol Version 4). That is, in Ethernet (registered trademark), a protocol for notifying the correspondence between an IPv6 address and a MAC address (an address unique to network I / F hardware) between devices communicating within a LAN. The ICMPv6 neighbor discovery packet includes a neighbor solicitation message corresponding to an ARP request in IPv4, a neighbor notification message corresponding to an ARP response in IPv4, and the like.

  The control sequence and packet flow when using the neighbor notification packet as the route change control data are the same as those in the case where the route change control data shown in FIG. 4 and FIG. Details are omitted.

  Changes 1. ARP requests 1061 and 1062 are changed to neighbor solicitation packets.

  Changes 2 The ARP response 1063 is changed to a neighbor notification packet.

  Changes 3 The ARP table is changed to the ND cache table.

  Regarding the changes 1 and 2, since the packet format also needs to be changed, the neighbor request, the message format of the neighbor notification packet, the source MAC address (912 in FIG. 3) of the ARP request / response, the source IP A brief description will be given of which fields in the neighbor solicitation / neighbor notification packet the address 913, the destination MAC address 914, and the destination IP address 915 correspond to. FIG. 11 simply shows the format of the neighbor solicitation packet and the neighbor notification packet. First, the control source MAC address 9201, target IP address 924, target MAC address 925, and destination IP address 9212 of the neighbor solicitation packet in FIG. 11 are the source MAC address 912 and the source IP address 913 in the ARP request in FIG. , Corresponding to the destination MAC address 914 and the destination IP address 915. Further, the start point MAC address 945, the source IP address 9411, the destination MAC address 9402, and the target IP address 944 of the neighbor notification packet in FIG. 11 are respectively the source MAC address 912, the source IP address 913 in the ARP response in FIG. It corresponds to the destination MAC address 914 and the destination IP address 915. When using the neighbor notification packet as the route change control data, it is desirable to enable the overwrite flag 943 present in the ICMPv6 header 942 in order to rewrite the ND cache of the device to be controlled more reliably.

  Note that the neighbor request packet can be used in the same manner as the ARP response packet can be used as the route change control data. As shown in FIG. 11, the format of the neighbor solicitation packet is the same as that of the neighbor notification packet and corresponds to the ARP request. Further, as a kind of ICMPv6 neighbor search packet, there is a router advertisement packet, which can be used as route change control data. The router advertisement packet is a message for the router to inform the host that is the device to be controlled that it is the default gateway. The host that is the control target device that has received this registers the IP address that is the transmission source of the router notification packet in the routing table as the IP address of the default gateway. The valid time is a value set in the “router valid time” field of the router notification packet. In this way, when the router notification packet is used as the route change control data, a packet in which the value of the “router valid time” field is set to 0 is used. At this time, the host that has received the router notification packet interprets that the source IP address of the router notification packet is no longer the default gateway, and deletes the entry from the routing table. As a result, the control target device can no longer transmit packets.

  In this state, when a router notification packet in which an arbitrary IP address is set as a transmission source IP address with a value other than 0 in the “router valid time” field is transmitted to the control target device as route change control data, the control target device is hereinafter referred to. Can recognize that the set IP address is the default gateway.

[When using ICMP route change packet]
Here, a procedure (procedure 1 to procedure 4) when an ICMP route change packet is used as route change control data for route change will be described.

  First, the function of the ICMP route change packet will be briefly described. Usually, route control in IP is performed by referring to the routing table of each device. In the routing table, an address of a router (this is referred to as a gateway) through which IP packets are first transmitted when an IP packet is transmitted to a network outside the LAN is set. When the ICMP route change packet is used as route change control data, the gateway address in the routing table of the device to be controlled can be rewritten, thereby changing the route of low priority communication. FIG. 12 shows a packet format of the ICMP route change packet. Hereinafter, the route change procedure when the ICMP route change packet is used in the network of FIG. 1 will be described with reference to FIGS. 13 to 15 in addition to FIGS. FIG. 13 is a schematic diagram showing a data flow in the QoS control procedure when an ICMP route change packet is used, and shows how each piece of data 1661 and 1662 exchanged moves on the network. FIG. 14 is an example of processing and data flow in the QoS control procedure when an ICMP route change packet is used, and shows a time series of each data exchange and QoS control processing in the first IP telephone 114 in this procedure. . FIGS. 15A and 15B are routing tables of the control target device, and show how the routing table 1621 of the PC 111 is updated as needed in the following procedure. In the following procedure, the MAC address and IP address of the PC 111, the first router 112, the server 113, the first IP telephone 114, and the fictitious device 115 are as defined in FIG.

(1) Procedure 1
The procedure 1 will be described with reference to FIG. First, in the present embodiment, the IP telephone communication performed by the first IP telephone 114 which is its own apparatus is a high priority communication, and all the communication from the LAN to the Internet via the first router 112 is a low priority communication. It is assumed that the QoS control unit 621 of the present invention operates. At this time, the priority information holding unit 841 in FIG. 2 has, as default information, an IP_router value necessary for route change control by the ICMP route change packet and an IP_PC value as the IP address of the control target device. Here, the IP_router is an IP address of the first router 112 that relays communication from the PC 111 and the first IP telephone 114 to the network 2 as shown in FIG. Note that this information is not predetermined information, and may be input from a user interface, or may be acquired by some procedure using a network.

  Next, the priority information holding unit 841 notifies the route change control unit 842 of this IP_router and IP_PC as information related to low priority communication (S851 in FIG. 2). Note that the IP address of the control target device is not included here, and the following procedure 2. May be acquired from a broadcast ARP request transmitted by the device to be controlled.

(2) Procedure 2
The procedure 2 and subsequent steps will be described with reference to FIGS. However, FIG. 12 is referred to regarding the format of the ICMP route change packet.

  Step S1701: The route change control unit 842 of the first IP telephone 114 transmits an ICMP route change packet as route change control data 1661. At this time, the source address of the IP header 931 of the ICMP route change packet is IP_router, and the destination address is IP_PC. Also, IP_None, which is the IP address of the fictitious device, is specified as the router IP address 933. Here, the IP address of the fictitious device is an arbitrary address different from the IP address of the device existing in the home LAN.

(3) Procedure 3
The routing table of the PC 111 before receiving the route change control data 1661 is as a table 1871 in FIG. 15A. IP_router is set as the IP address of the gateway that transfers the packet addressed to the server 113 in FIG.

  Step S1702: Here, when the PC 111 receives the route change control data 1661, it updates its own routing table. At this time, the routing table is as shown in the table 1872 of FIG. 15B, and the fictitious IP address IP_None is associated as the transfer destination of the packet addressed to the server 113.

(4) Procedure 4
Step S1703: Through the above processing, when the PC 111 transmits communication data to the server 113, it tries to transmit low priority communication data using the IP address of the fictitious device as a gateway.

  Step S1704: At this time, in order to actually transmit data, since the PC 111 needs to know the MAC address for the fictitious IP address IP_None, it transmits a broadcast ARP request 1662. However, since there is no device having the designated destination IP address 915, the ARP request 1662 is discarded. As a result, the PC 111 cannot transmit the low priority communication data, and the communication between the PC and the server after the path change is interrupted.

  The interrupted low priority communication can be resumed by transmitting the return control data as the route change control data that restores the routing table of the PC 111 that is the control target device. Furthermore, it is possible to adjust the communication amount of low priority communication by adjusting the interval between interruption and resumption. When the interruption and restart processes are repeated a plurality of times, the procedure 1 may be omitted for the second and subsequent times. If the transfer speed of the access line 106 shown in FIG. 1, which is a line where congestion occurs, is known, what interval should be interrupted and resumed to secure QoS for high priority communication from that value? You can also decide if it ’s good. At this time, the relational expression between the transfer speed of the access line 106 and the interval of interruption / resumption can be obtained by conducting an experiment, for example.

  Furthermore, when high-priority communication ends, the routing table of the control target device is restored to the original by the above-described method, so that after high-priority communication ends, the communication path before the path change is restored, and low-priority communication is performed. The communication 131 between the PC and the server can be continued.

  The ICMP route change packet described above can be used only in an IPv4 network, but an ICMPv6 route change packet that exhibits the same effect can be used in an IPv6 network. The processing when the ICMPv6 route change packet is used as the route change control data is the same as that when the ICMP route change packet is used, and the details are omitted here.

[When using DNS reply packet]
Here, a procedure (procedure 1 to procedure 4) when using a DNS reply packet as route change control data for route change will be described.

  First, DNS (Domain Name System) will be briefly described. DNS is a function for obtaining a corresponding IP address from a host name indicated in a name format called FQDN (Fully Qualified Domain Name) (eg, www.panasonic.co.jp).

  In order to use the DNS, the communication application transmits a DNS inquiry packet including the FQDN to the DNS server. On the other hand, a DNS reply packet (including an IP address corresponding to the inquired FQDN) transmitted from the DNS server is received, and thereafter, communication is performed with respect to the IP address.

  Hereinafter, a route change procedure when a DNS reply packet is used will be briefly described with reference to FIGS. 1, 2, and 8. The relationship between FIGS. 1 and 2 and FIG. 8 are as already described.

(1) Procedure 1.
The procedure 1 will be described with reference to FIG. First, in the present embodiment, the IP telephone communication performed by the first IP telephone 114 which is its own apparatus is a high priority communication, and all the communication from the LAN to the Internet 2 via the first router 112 is a low priority communication. Assuming communication, the QoS control unit 621 of the present invention operates. At this time, the priority information holding unit 841 in FIG. 2 has the IP_router value and the MAC_router value necessary for route change control by the DNS reply packet as default information. Note that this information is not predetermined information, and may be input from a user interface, or may be acquired by some procedure using a network.

  Next, the priority information holding unit 841 notifies the route change control unit 842 of the IP router and the MAC_router as information related to low priority communication (see S851 in FIG. 2).

(2) Procedure 2
Here, the method once used in the case of the ARP request / ARP response / ICMP path change packet is applied to change the destination of the DNS inquiry packet and direct it to the first IP telephone 114 having the QoS control unit 621 of the present invention. The IP_router acquired as information related to low priority communication is used here.

  The first IP telephone 114 receives the DSN inquiry packet and stores various information necessary for creating a DNS answer packet such as FQDN included therein. The route changed by the ARP request / ARP response / ICMP route change packet may be returned at an arbitrary timing thereafter.

  The route change control unit 842 of the first IP telephone 114 transmits a DNS reply packet as route change control data to the PC 111 that is a device to be controlled. At this time, IP_None (see FIG. 8), which is the IP address of the fictitious device corresponding to the FQDN included in the DNS inquiry packet, is set. Note that the source IP address and destination IP address of the route change control data are obtained by replacing the source IP address and destination IP address of the DNS inquiry packet. In addition, an IP_router acquired as information on low priority communication is set in the source MAC address.

(3) Procedure 3.
The PC 111 that is the control target device that has received the route change control data transmits low priority communication data with a nonexistent IP address as a destination.

(4) Procedure 4.
However, it is detected that no destination host exists in any router on the communication path, and an ICMP destination unreachable message is transmitted to the PC 111. Receiving this, the PC 111 detects an error, and usually the communication application interrupts communication.

  In <Installation Position>, it is described that the PC 111 as the control target device and the first IP telephone 114 having the QoS control unit 621 of the present invention need to be in the same LAN. However, when the DNS reply packet is used as the route change control data, it is not always necessary that the control target device and the first IP telephone 114 having the QoS control unit 621 of the present invention exist in the same LAN. For this reason, the device to be controlled may be any of the devices at both ends that perform low priority communication. In addition, the place where the first IP telephone 114 having the QoS control unit 621 of the present invention is present may be anywhere as long as IP communication with the control target apparatus is possible.

  The above DNS reply packet can be used in both IPv4 and IPv6.

[When using DHCP and DHCPv6]
Next, a case where DHCP and DHCPv6 are used will be described. DHCP (Dynamic Host Configuration Protocol) is a protocol for acquiring information such as an IP address of a host that is a client, a default gateway to be used, a DNS server, and the like from a server, and can be used in an IPv4 network. In DHCP, after a client exchanges a message for detecting a server, a DHCPREQUEST (DHCP request) packet is transmitted to the detected server, and a DHCPACK (DHCP response) transmitted from the server in response to this packet is transmitted. The client is set by receiving the packet (including the information described above).

  DHCPv6 is a protocol that can be used in IPv6 and provides almost the same functions as DHCP. However, DHCPv6 is different from DHCP in that a default gateway cannot be set. In DHCP, processing is always performed in such a manner that the server responds to a request from the client, whereas in DHCPv6, a RECONFIGURE (re-setting) packet for overwriting setting from the server side can be used.

  By using the DHCPACK packet or RECONFIGURE packet in these protocols as the route change control data, the default gateway of the control target device is changed, and the same effect as the case of using the ICMP route change packet described above can be obtained, or the control target By changing the DNS server to be referred to, it is possible to obtain the same effect as the prior route changing method based on the ARP request or the like when the DNS reply packet is used.

  Note that DHCP is specified in RFC2131 and DHCPv6 is specified in RFC3315.

[When using software on a PC]
Here, a procedure (procedure 1 to procedure 4) in the case where the path change control is performed using software installed in the PC will be described.

  When the control target device is a general-purpose computer such as a PC, the data path transmitted by the control target device can be changed by installing software therein. It is assumed that the software has been installed on the PC before this procedure starts. Hereinafter, the procedure will be described with reference to FIGS. 1, 2, and 12. The relationship between FIGS. 1 and 2 and FIG. 12 are as already described.

(1) Procedure 1
In this method, the procedure 1 for notifying the low-priority communication of information from the priority information holding unit 841 to the route change control unit 842 is unnecessary.

(2) Procedure 2.
The route change control unit 842 of the QoS control unit broadcasts a special packet that can be recognized by software installed in the PC 111 as route change control data. If the address (IP_PC or MAC_PC) of the PC 111 that is the control target device is known in advance, unicast may be used. In the route change control data, an address that does not exist is set as information on the address to be transferred. If the transfer destination address is known in advance, it may be registered in advance in the PC software.

(3) Procedure 3
The PC 111 that is the control target device that has received the route change control data rewrites its own ARP table or routing table, or rewrites the destination MAC address or IP address of the communication data by some method by processing of software installed in advance. .

(4) Procedure 4
Thereafter, the PC 111 transmits low priority communication data with a non-existing MAC address or IP address as the destination, and as a result, the low priority communication between the PC and the server is interrupted.

  The interrupted low-priority communication can be resumed by transmitting route change control data that restores the data transfer destination of the control target device. Furthermore, it is possible to adjust the communication amount of low priority communication by adjusting the interval between interruption and resumption.

  Furthermore, when high-priority communication ends, the ARP table of the control target device is restored to the original by the above-described method, so that after high-priority communication ends, the communication path before the path change is restored and low-priority communication is performed. The communication 131 between the PC and the server can be continued.

<Route change timing>
Up to this point, the route is changed at the start of high priority communication as the timing for changing the route, and the timing for returning the route is at the end of the high priority communication. However, the present invention is not limited to this. Hereinafter, the timing of route change will be described.

  The timing at which the route change control data can be transmitted to the control target device varies depending on the route change control data. For example, when the route change control data is an ARP request, the route change control data can be transmitted at an arbitrary timing as long as the control target device once transmits the ARP request. However, in the case where the route change control data is a DNS reply packet, after the control target device transmits a DNS inquiry packet, the DNS reply packet reception waiting process cannot be received due to a timeout until the DNS reply packet cannot be received. The route change control data from the first IP telephone 114 having the QoS control unit 621 must be received.

  Although the timing at which the route change control data can be transmitted varies depending on the route change control data, the timing for changing the communication route based on the received route change control data and the effect thereof will be described below. However, this does not limit the timing of applying the present invention to the following, and may be performed at an arbitrary timing.

  First, the timing for changing the communication path of low priority communication from the normal communication path to another communication path can be considered as follows.

  Timing 1. The timing for changing the communication path of the low priority communication is determined when the first IP telephone 114 having the QoS control unit 621 of the present invention is powered on or the first IP telephone 114 having the QoS control unit 621 of the present invention is connected to the home LAN. Or the first time after that, that is, the timing at which processing can be started upon receipt of an ARP request packet. In this case, it is possible to change the route permanently, and the implementation is easy.

  Timing 2. The timing for changing the communication path of the low priority communication is the timing at which the high priority communication is started. In this case, since the communication path can be changed only during a period in which there is a possibility that communication may compete, it is possible to reduce the influence of low priority communication due to the change of the communication path.

  Timing 3. The timing for changing the communication path of the low priority communication is the timing when the quality of the high priority communication is deteriorated. In this case, the control is complicated, but the period in which the communication path is changed is set to the timing 2 described above. It can be made even shorter. It should be noted that the criterion for quality degradation is determined from statistical information of information (delay, jitter, packet loss rate, etc.) relating to the quality of high priority communication. As a method for the first IP telephone 114 having the QoS control unit 621 of the present invention to acquire information relating to the quality of high priority communication, quality information is collected in a device that terminates high priority communication, and a packet including the information is collected. Is easily transmitted to the first IP telephone 114. Furthermore, when a QoS control unit exists in a device that terminates high-priority communication, quality information can be passed within the device.

  Next, the timing for returning the communication path once changed can be considered as follows.

  Timing 1. The timing for returning the communication path to the original time is when the first IP telephone 114 having the QoS control unit 621 of the present invention is shut down or restarted. In this case, it is possible to eliminate the influence on the low priority communication during the period in which the first IP telephone 114 cannot be controlled.

  Timing 2. The timing for returning the communication path to the original timing is the timing when the high priority communication ends. In this case, since the path can be changed only during a period in which communication may compete, it is possible to reduce the influence of low-priority communication due to the path being changed.

  Timing 3. The timing for returning the communication path to the original timing is a timing when it is determined that the quality of the high-priority communication is ensured even if the communication path is returned due to a decrease in the communication amount of the low-priority communication. In this case, the control is complicated, but the period during which the communication path is changed is set to 2. It can be made even shorter. Note that the criterion for determining whether high-priority communication quality is ensured even when the route is returned is determined based on statistical information on information (delay, jitter, packet loss rate, etc.) regarding the quality of high-priority communication. . As a method for the first IP telephone 114 to acquire information on the quality of high-priority communication, quality information is collected in a device that terminates the high-priority communication, and a packet including the information is transmitted to the first IP telephone 114. How to make it easy. Furthermore, when a QoS control unit exists in a device that terminates high-priority communication, quality information can be passed within the device.

  The priority information holding unit in the claims corresponds to the priority information holding unit 841, and the route change control unit in the claims corresponds to the route change control unit 842.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 16 is a network configuration diagram according to the second embodiment. In FIG. 16, the PC 111 and the first IP telephone 114 are connected to the LAN side of the first router 112 existing in the first home 101 to form a home LAN. The home LAN is connected to the Internet 102 via the access line 106 and the first ISP 103. The second router 116 is also present in another second home 104, and a second IP telephone 117 is connected to the LAN side. The home LAN of the second home 104 is connected to the Internet 102 via the second ISP 105.

  In FIG. 16, file transfer 131 (hereinafter referred to as PC-server communication 131) is transferred between the PC 111 in the first home 101 and the server 113 on the Internet 102, and the first IP telephone 114 in the first home 101. IP telephone communication 132 (hereinafter referred to as IP telephone-IP telephone communication 132) using the Internet 102 is performed with the second IP telephone 117 in the second home 104.

  In FIG. 16, the QoS control unit 121 is mounted as one function unit of the IP telephone 114. FIG. 17 shows in more detail the internal configuration of the IP telephone 114 and the QoS control unit 121 in FIG. As illustrated in FIG. 17, the QoS control unit 121 includes a priority information holding unit 841, a path change control unit 842, and a communication control unit 120. The communication control unit 120 controls output of transmission data from the low priority communication apparatus to the network, and includes an analysis unit 127, a selection unit 128, and an adjustment unit 126. The route change control unit 842 can receive data from the LAN line 107 and transmit data to the LAN line 107 via the communication processing unit 123 in the IP telephone 114. Here, it is assumed that the communication processing unit 123 conforms to the Ethernet (registered trademark) protocol. That is, the communication processing unit 123 includes a PHY unit 172 and an EtherMAC unit 171. The voice data of the IP phone is generated by the voice data generation unit 122 and transmitted to the LAN line 107 via the communication processing unit 123. Here, the communication 132 between the IP phone and the IP phone is a communication that requires real-time property, and is a high priority communication with a high priority. On the other hand, the communication 131 between the PC and the server is a low priority communication with a low priority. The first IP telephone 114 is a high priority communication device, and the PC 111 is a low priority communication device.

  The difference of this embodiment from the first embodiment is as follows. In the first embodiment, when a route is changed, low priority communication is interrupted by recognizing an address that does not exist for the control change target device as a destination, whereas in the second embodiment, control is performed. By causing the change target device to recognize the address of the first IP telephone 114 having the QoS control unit 121 as a destination, the QoS control unit 121 once receives low-priority communication data. That is, in the first embodiment, the QoS control unit only changes the communication path, whereas in the second embodiment, the QoS control unit 121 further includes an analysis unit 127, a selection unit 128, and an adjustment unit 126. And performs more detailed control on the received low priority communication data.

  Hereinafter, in the second embodiment, as shown in FIG. 16, the first IP telephone 114 having the QoS control unit 121 of the present invention sets the communication path of the low-priority PC-server communication 131 to the first IP telephone. The procedure for securing QoS for high-priority communication by performing detailed QoS control in the first IP telephone 114 will be described. The outline of the QoS control process of the present invention will be described first in <Overall flow of QoS control process>, and then the details of each procedure will be described in <Detailed procedure of QoS control process>.

<Overall flow of QoS control>
The QoS control process in the second embodiment is roughly performed according to the following procedure.

  First, as a state before the QoS control process is performed, it is assumed that only low priority communication (PC-server communication 131) is performed in the network of FIG. Thereafter, when high-priority communication (IP phone-IP phone communication 132) is started, the QoS control unit 121 performs the following control. Hereinafter, a description will be given with reference to FIG.

(1) Procedure 1
The priority information holding unit 841 holds priority information for distinguishing between low priority communication and high priority communication, and notifies this to the route change control unit 842 (S851). Here, the first IP telephone 114 is set as a high priority communication apparatus that performs high priority communication, and the PC 111 is set as a low priority communication apparatus that performs low priority communication.

(2) Procedure 2
The route change control unit 842 obtains information such as an IP address necessary for generating route change control data for route change (S852). The information collected here differs depending on the route change method.

  The route change control unit 842 generates route change control data from the information acquired here and the information obtained by the procedure 1, and sends the route change control data to the PC 111 that terminates or relays the low-priority communication that is the control target device for the route change. Then, route change control data for route change is transmitted (S853).

  The communication processing unit 123 sends this route change control data to the LAN line 107. The route change control data includes information on the destination after the change of the data output from the PC 111 which is a low priority communication device. In the present embodiment, the address of the first IP telephone 114 itself having the QoS control unit 121 of the present invention is used as the destination after the change.

(3) Procedure 3
The PC 111 that is a low-priority communication device and is a device to be controlled is a communication device that has received the route change control data and has changed the data of the subsequent low-priority communication, that is, the QoS control unit 121. It transmits to the route via the first IP telephone 114.

(4) Procedure 4
The QoS control unit 121 receives the low priority communication data via the communication processing unit 123 (S1951), and the analysis unit 127, the adjustment unit 126, the selection unit 128, etc. The process is performed, and then transferred to the correct destination (S1952). The communication path of the low priority communication at this time is the PC-server communication 133 after the path change in FIG.

<Detailed procedure for QoS control>
Next, the detailed procedure when the above procedure is performed will be described with reference to FIGS. 17 to 20 in addition to FIG. 16 with respect to steps 1 to 4 of <Overall flow of QoS control processing>. This will be described below. FIG. 17 is a block diagram of the QoS control unit and the IP telephone in the second embodiment, and shows the time series of each data exchange and processing in the first IP telephone 114 in this procedure. FIG. 18 is an example of processing and data flow when performing detailed control after route change control. 19 and 20 show how the ARP table and routing table of the PC 111 are updated as needed.

  Hereinafter, it demonstrates along the flow of a process.

(1) Procedure 1
The procedure 1 will be described with reference to FIG. First, in the present embodiment, the IP telephone communication performed by the first IP telephone 114 which is its own apparatus is a high priority communication, and all the communication from the LAN to the Internet 2 via the first router 112 is a low priority communication. Assuming communication, the QoS control unit 621 of the present invention operates. At this time, the priority information holding unit 841 in FIG. 17 has the IP_router value necessary for route change control by the ARP request as default information.

Next, the priority information holding unit 841 notifies the IP_router to the route change control unit 842 as information on low priority communication (see S851 in FIG. 17).
(2) Procedure 2
Step S1401: Next, the PC 111, which is a device in the LAN that terminates the low-priority communication, is the IP address of the first router 112 that first passes to communicate with the server 113, as in S1201 of FIG. A broadcast ARP request 1061 is transmitted with the IP_router as the destination IP address 915.

  Note that the routing table of the PC 111 after receiving the ICMP route change packet is as shown in a table 1873 of FIG. In addition, the above difference does not depend on whether the route change control data uses an ARP request / ARP response / ICMP route change packet / DNS reply packet / special packet that can be recognized by software on the PC. In the embodiment, description on <route changing method> is omitted.

  Thereafter, the route change control unit 842 in the QoS control unit performs the route change control data generation process of S1402. Only the change destination address of the communication path set by the path change control data is different from that of the first embodiment, and the details of the other processes are the same as those in the flowchart of FIG. To do. The destination IP address 915 and the source address 913 specified here are obtained by replacing the destination IP address 915 and the source IP address 913 of the received ARP request 1061. Further, MAC_QoS which is the MAC address of the first IP telephone 114 having the QoS control unit 121 is set in the transmission source MAC address 912.

(3) Procedure 3
Step S1405: The PC 111 that is the control target apparatus that has received the path change control data 1062 updates the APR table based on the path change control data 1062. The state of the APR table at this time is as shown in the table 1174 of FIG. 19, and MAC_QoS, which is the MAC address of the first IP telephone 114 having the QoS control unit 121, is registered as the MAC address corresponding to the IP_router. Yes.

(4) Procedure 4
Step S1406: Next, the PC 111 performs communication data transmission processing. At this time, since the low-priority communication path has already been changed to the first IP telephone 114 having the QoS control unit in the procedure 3, the communication data 2061 is transmitted to the first IP telephone 114.

  The first IP telephone 114 receives the communication data 2061, performs detailed control (S2001), and transmits it. Hereinafter, an example of reception processing and transmission processing (including detailed control) will be described with reference to FIGS. 17, 21, 22, and 23.

[Reception processing]
The Ethernet (registered trademark) frame (FIG. 21A) detoured to the first IP telephone 114 is extracted by the Ethernet (registered trademark) MAC unit 171 via the PHY unit 172. The Ethernet (registered trademark) MAC unit 171 sends the destination address (DA), transmission source address (SA), type, and payload data of the extracted frame to the analysis unit 127 in the QoS control unit 121.

  The analysis unit 127 performs the operation shown in FIG. That is, when an Ethernet (registered trademark) frame (DA, SA, type, data) is received from the Ethernet (registered trademark) MAC unit 171 (S601 in FIG. 22), an IP protocol packet is stored in the frame from the type area. Find out if it is. If the value of the type is 0x0800, this is an IP protocol and a candidate for reception by the own device (first IP telephone 114) (S602). Next, as shown in S603, the destination IP address is checked from the IP header (FIG. 21C) in the Ethernet (registered trademark) frame (FIG. 21B), and it is determined whether or not it is a reception target. If it is a reception target, the frame is sent to the TCP / IP processing unit 124, which is the upper processing unit (S604). Those not in the IP protocol in S602 and those not addressed to themselves in S603 are written to the adjustment unit 126 (S605), and the DA and SA of the frame are rewritten by the adjustment unit 126 (S605). Specific contents to be rewritten will be described later. The adjustment unit 126 includes a storage unit that can store frames. In addition, the accumulation unit does not need to be included in the adjustment unit 126 and may be provided independently of the adjustment unit 126.

  The TCP / IP processing unit 124 performs TCP / IP protocol processing on the Ethernet (registered trademark) frame received from the analysis unit 127 and transmits it to an appropriate terminal application such as the IP phone application 122.

[Transmission process]
The transmission data from the IP telephone application 122 is subjected to transmission protocol processing by the TCP / IP processing unit 124, which is an upper processing unit, to form an Ethernet (registered trademark) frame, and is sent to the selection unit 128 in the QoS control unit 121. A send request is issued.

  The selection unit 128 performs the operation shown in FIG. That is, when there is a transmission request from the TCP / IP processing unit 124 (S701), the frame is read (S702) and transmitted to the Ethernet (registered trademark) MAC unit 171 (S705). On the other hand, if there is no request from the TCP / IP processing unit 124 (S701), then it is checked whether there is a transmission request from the adjusting unit 126 (S703) (note that a control data packet transmission request from the path change control unit) Etc., it is handled in the same manner as the transmission from the adjustment unit 126). If there is a transmission request from the adjustment unit 126, the frame is read from the adjustment unit 126 (S704) and transmitted to the Ethernet (registered trademark) MAC unit 171 (S705). When frame transmission is completed (S705), it is checked again whether there is a transmission request from the TCP / IP processing unit 124 (S701).

  The Ethernet (registered trademark) MAC unit 171 that has received the frame to be transmitted performs MAC processing such as adding an FCS (frame check sequence) and sends the frame to the transmission path via the PHY unit 172.

  In particular, by realizing each of the analysis unit, the adjustment unit, and the selection unit in hardware, a CPU that executes a terminal application or TCP / IP processing can avoid processing a frame that is not addressed to its own device. The transmission / reception frame of the PC 111 is not affected.

  Now, how the first IP telephone 114 operating as described above acts on the frame transmitted from the PC 111 to the server 113 to perform priority control will be described.

  First, as described above, an Ethernet (registered trademark) frame addressed to the server 113 from the PC 111 passes through the first IP telephone 114. In that case, the Ethernet (registered trademark) frame sent from the PC 111 originally sent the MAC address of the first router 112 as the destination address, but after the ARP table or the like was rewritten due to the route change, the first IP telephone 114 Is the destination address. However, since there is no change in the server 113 that is the communication partner, the destination IP address remains the IP address of the server 113.

  Since the destination MAC address of the Ethernet (registered trademark) frame transmitted from the PC 111 is the first IP telephone 114, it is detoured to the first IP telephone 114. In the first IP telephone 114, since the destination IP address of the frame is not the server itself but the server 113, the analysis unit 127 writes to the adjustment unit 126 as described above with reference to FIG. That is, the destination MAC address is set in the first IP telephone 114, but the IP address of the server 113 that is the original destination is set as the destination IP address of the upper protocol. For this reason, an Ethernet (registered trademark) frame sent from the PC 111 to the server 113 but bypassed to the first IP phone by rewriting the ARP table and sent to the server 113 and the Ethernet addressed to the first IP phone 114 itself. The (registered trademark) frame can be distinguished by the analysis unit 127. Further, the adjustment unit 126 sets DA, which is the destination MAC address of the stored frame, to the MAC address of the first router 112 (the packet relayed as shown in FIG. 18 is once transferred to the router (S2002), then the server 113 (S2003), the source MAC address SA is rewritten to its own MAC address. The transmission frame of the PC 111 stored in the adjustment unit 126 is selectively multiplexed by the selection unit 128 as described above with reference to FIG. At this time, if there is a transmission frame from the IP telephone application of the first IP telephone 114, the transmission frame is selected and transmitted with priority. Therefore, the first IP telephone 114 transmits its own transmission frame (voice data) as the PC 111 transmission frame. Will be prioritized.

  24, 35, and 36, the relationship between the arrival (transmission request) and transmission (reading) at the selection unit of the transmission frame from the first IP telephone 114 (own transmission frame) and the relay frame received from the PC 111 is shown. . These are for explaining the detailed operations of transmission / reception and relay processing described so far (depending on whether the adjustment unit 126 has a buffer and whether the LAN line 107 is full duplex or half duplex). is there.

  First, FIG. 24 shows a case where the adjustment unit 126 has a buffer and the LAN line 107 is full duplex.

  In the case of (a) and (e): When there is no self-sending frame when the relay frame arrives and when there is no self-sending frame when transmission of the relay frame is completed, it is relayed as it is.

  In the case of (b): There is no self-sending frame when the relay frame arrives, but when a sending request for the self-sending frame is generated when the relay frame is being sent, the relay frame is sent at time t3. Upon completion, even if there is a request for transmission of the next relay frame from the adjustment unit 126, the self-sending frame is sent immediately and transmission is completed at time t4.

  Cases (c) and (d): This is a case where the relay frame arrives while the self-sending frame is being transmitted, and the relay frame starts to send the relay frame as soon as the self-sending frame has been sent (time t2). . Since the size of the buffer in the adjustment unit 126 is assumed to be large enough to store the frame, the relay frame can be kept waiting during the transmission of the self-sending frame.

  On the other hand, if the buffer size in the adjustment unit 126 is small, for example, equivalent to an elastic memory, as shown in FIG. 25, when a relay frame arrives while sending out its own transmission frame ((c) and (d) in FIG. 8). ), The relay frame is discarded.

  Further, the buffer in the adjustment unit 126 has a capacity capable of storing frames, and when the transmission path is half duplex, the transmission timing is as shown in FIG. That is, since it is a half-duplex transmission line, it cannot be transmitted during reception.

  In the case of (a): the self-sending frame cannot be sent until the relay frame is completely sent.

  In the case of (b): Although the relay frame has completed arrival, since there is a self-sending frame, the relay frame is sent first after sending the self-sending frame.

  In the case of (c): Since the self-sending frame is being sent, the relay frame cannot be received at this timing. The relay frame arrives at the timing (d).

  In the case of (d) and (e): When the relay frame arrives, there is no self-sending frame, so that it is sent as soon as the reception of the relay frame is completed.

  In the description so far, the selection unit 128 transmits the communication data 2062 for low priority communication only when there is no transmission request for high priority communication from the TCP / IP processing unit 124. Regardless of the presence or absence of communication data, the transmission data of the low-priority communication device may always be extracted from the buffer after a predetermined time and output to the network. Thus, by always outputting the low priority communication to the network after a certain time has elapsed, it is possible to perform control for ensuring the QoS of the high priority communication regardless of the presence or absence of the high priority communication.

<Detailed control after route change>
The detailed control performed by the first IP telephone 114 having the QoS control unit 121 of the present invention has been described as the priority control performed by the dedicated router in FIG. Any of the control methods may be used.

  However, priority control between such high-priority communication data and low-priority communication can be performed in FIG. 16, in which one function unit of the first IP telephone 114, which is the high-priority communication termination device, is the present invention. Because there was. When the first IP telephone 114 is not the same device as the high-priority communication termination device, for example, in the case of the position 1583 in FIG. 9 described above, the various route changing methods described so far are used. After changing the route of the high priority communication so as to pass through the first IP telephone 114, priority control between the high priority communication and the low priority communication may be performed in the selection unit 128. Note that the high-priority communication and low-priority communication paths at this time are the IP telephone-IP telephone communication 1531 after the path change and the PC-server communication 133 after the path change shown in FIG. become that way. In this case, the selection unit 128 uses, as priority information for distinguishing between low priority communication and high priority communication, an IP address or transport layer protocol (characterizing the low priority communication or high priority communication data). It is necessary to pass information such as TCP and UDP) and port number from the priority information holding unit 841 to the selection unit 128 (S1953). It should be noted that the information held by the priority information holding unit 841 may be a predetermined value, may be input from the user interface, or may be obtained by some means using a network. Also good.

  Further, even if the communication device of the present invention having the QoS control unit 121, which is exemplified by the first IP telephone 114, is different from the high-priority communication termination device, it can be performed without changing the high-priority communication route. There is also detailed control. In these cases, the adjustment unit 126 does not directly pass the low-priority communication received from the analysis unit 127 to the selection unit 128, but temporarily passes it to the adjustment unit 126, and returns the data returned from the adjustment unit 126 to the selection unit. Works to pass. In these cases, the selection unit 128 may transmit the received data in order without performing priority control.

  Some examples of detailed control in such a case will be described below, but some of them are processed by the adjustment unit 126.

  1. The adjustment unit 126 of the communication apparatus of the present invention discards part or all of the low priority communication packet.

  2. When the low-priority communication is TCP (Transmission Control Protocol), the adjustment unit 126 of the communication apparatus of the present invention rewrites the value of the window field existing in the TCP header to a smaller value and returns the packet to the original destination of the packet. Forward. Upon receiving this packet, the original destination device subsequently reduces the data transmission rate (window size) by TCP general flow control. As described above, the destination device controls the transmission rate of transmission data to the low priority communication device, but conversely controls the transmission rate from the low priority communication device to the partner communication device. Data may be generated and transmitted to the low priority communication device.

  3. When the low-priority communication is TCP (Transmission Control Protocol), the adjustment unit 126 of the communication apparatus according to the present invention uses one Ack packet having a sequence number included in the TCP header of the Ack (Acknowledgement Response) packet. One or more are generated and transferred to the original destination of the packet. When the device that is the original destination receives these Ack packets, the data transmission rate (window size) is subsequently lowered by TCP flow control.

  4). When the low-priority communication is TCP (Transmission Control Protocol), the adjustment unit 126 of the present invention delays for a certain time from receiving to transferring to the original destination. At this time, the transmission timing of the next packet is similarly delayed by the TCP flow control, so that the data transmission rate is lowered thereafter.

  5. The path change control unit 842 of the communication apparatus of the present invention may further include a QoS value holding unit (not shown) that holds a QoS value set to hold the quality of high priority communication. Then, the route change control unit 842 calculates a value indicating the quality of the higher priority communication based on the traffic volume of the communication, and compares the calculated value indicating the quality with the QoS value. Here, when the value indicating the calculated quality is smaller than the QoS value, route change control data is transmitted. Therefore, by changing the communication path for low-priority communication according to the deterioration of the quality of high-priority communication, the communication path for high-priority communication can be secured only during the necessary period, The influence on the priority communication can be eliminated. Note that the value indicating the quality of the high priority communication can be obtained from the traffic volume, the application used for the telephone, the value indicating the sound quality, and the like.

<Packet size change control>
Further, in the detailed control after the route change, the QoS of the IP telephone communication can be further improved by performing a process for reducing the packet size of the low priority communication in addition to the priority control described so far.

  The phenomenon that the QoS of the IP telephone communication is lowered when the packet size of the low priority communication is large has already been described as the phenomenon 4 in the “Background Art”, and thus the description thereof is omitted here.

  Methods for reducing the packet size of low-priority communication are broadly divided into (1) a method in which the QoS control device divides and transmits received low-priority communication packets, and (2) a low-priority communication device (for example, PC111). Etc.), there are two types of methods for reducing the size of the packet itself transmitted.

(1) Method of Dividing (Fragmenting) Low-priority Communication Packets Received by QoS Control Device by Coordinator 126 As a method of dividing and transmitting low-priority communication packets received by QoS control device It is easiest to perform IP fragment processing. The IP fragment by a normal router is for dividing the packet into a plurality of packets having a size equal to or smaller than the MTU when the size of the packet transferred by the router exceeds the MTU (Maximum Transfer Unit) of the access line. . However, here, regardless of the MTU value of the access line, for example, a packet of 1500 bytes (IP data size minus IP header 20 bytes is 1480 bytes) and a packet of 300 bytes (IP data size is 280 bytes) Divide into packets. As a result, the time taken for each fragmented packet to be transmitted to the access line (the maximum time that the voice data waits in the router) is 300/1500 = 1/5. Therefore, increase in delay time and fluctuation of IP telephone communication can be suppressed.

  Here, the flow of a packet when an IP fragment occurs will be briefly described with reference to FIG. First, the PC 111 transmits a 1500-byte data packet 2601 as usual. Here, as described above, the destination of the communication path of the PC 111 that is the low priority communication is changed to the first IP telephone 114 that is the high priority communication. Upon receiving the data packet 2601 from the PC 111, the QoS control unit 121 of the first IP telephone 114 of the present invention first performs IP fragment processing. Then, the QoS control unit 121 transmits the plurality of divided data packets 2611 to 2616 to the server 113. In each fragmented data packet 2611 to 2616, a value indicating the positional relationship of each data packet in the original data packet 2601 is set in the fragment offset field of the IP header, as in the case of a normal IP fragment. That is, a value indicating where the head of the data included in each data packet is located from the head of the data of the original data packet 2601 is set. In a fragment packet other than the last fragment packet 2616, a more fragment flag indicating that there is a subsequent fragment packet is set.

  The data dividing method in the present invention may be any method and is not limited to IP fragments. For example, in addition to the division by IP fragment, a method of extracting a TCP data stream from a series of IP packets, dividing the data again into an appropriate size, and sending each as an IP packet, a plurality of IP packets in a data link layer It is also possible to divide the data sequence into data strings (the Ethernet (registered trademark) protocol cannot use this method, but it can be used when a data link protocol capable of such a method is defined in the future). .

  In addition, when the fragment prohibition bit of the IP header is set, or in the provisions regarding IP fragments in IPv6, it is prohibited to perform fragmentation in the relay device. However, even if IP fragmentation is performed against these rules, it is possible to continue communication normally, and the present invention includes the case where IP fragment is performed for these packets.

(2) A method of reducing the size of a packet transmitted by a low-priority communication source device As a method of reducing the packet size at the time of transmission by a low-priority communication source device, an MSS included in a TCP SYN packet There are a method of changing (Maximum Segment Size), a method of changing an MTU (Maximum Transfer Unit) of a low-priority communication apparatus using an ICMP destination unreachable Fragment Needed packet, and the like. However, the present invention is not limited to these methods.

(2-1) Changing MSS First, a method for changing the MSS of a SYN packet will be described. FIG. 28 shows a format of a TCP SYN packet with the MSS option. MSS is a value defined in TCP and is the maximum data size when data is divided. The MSS is a value defined for storing data received from an application in each IP packet. The MSS is determined as follows. First, a SYN packet is transmitted from both devices at the start of a TCP session, and the value of the MSS field included in the SYN packet is compared. The MSS is determined by selecting the smaller MSS among these.

  A procedure for using this mechanism to reduce the size of a packet transmitted by a transmission source device of low priority communication will be described with reference to FIG. Here, as described above, the destination of the communication path of the PC 111 that is the low priority communication is changed to the first IP telephone 114 that is the high priority communication.

  First, the PC 111 transmits a SYN packet 2701 to the server 113 when starting a TCP session. At this time, the PC 111 sets 1460 as the value of the MSS field (a value obtained by subtracting the IP header (20 bytes) and the TCP header (20 bytes) from the Ethernet MTU size 1500 bytes is often used).

  As the route is changed as described above, the first IP telephone 114 receives the SYN packet transmitted from the PC 111 to the server 113. Then, the adjustment unit 126 in the QoS control unit of the first IP telephone 114 changes the value of the MSS field of the SYN packet to a smaller value, for example, 260, and transfers it to the server 113 (S2711). At this time, the QoS control unit also needs to correct the checksum field in the TCP header.

  Next, the server 113 compares the value 260 of the MSS field of the received SYN packet with the value of MSS (1460 here) set in the SYN packet transmitted by itself. Then, the server 113 sets 260, which is the smaller value, as the MSS value of the server 113 (S2712).

  Next, the server 113 transmits a SYN packet to the PC 111. At this time, the server 113 sets 1460 as the value of the MSS field. Since the path change has been performed as described above, the first IP telephone 114 receives the SYN packet from the server 113. The adjustment unit 126 of the first IP telephone 114 changes the value of the MSS field of the received SYN packet to a smaller value, for example, 260, and forwards it to the PC 111 (S2713). At this time, the checksum field in the TCP header also needs to be corrected.

  Next, the PC 111 that has received this compares the MSS field value 260 of the received SYN packet with the MSS value 1460 set in the SYN packet transmitted by itself. The smaller value 260 is set as the MSS value of the PC 111 (S2714). Thereafter, the size of the TCP packet transmitted by the PC 111 and the server 113 is 300 bytes (TCP data 260 bytes + TCP header 20 bytes + IP header 20 bytes).

  In this example, the MSS field of the SYN packet transmitted by both apparatuses is rewritten. However, when only the size of the packet transmitted from the PC 111 is desired to be reduced, only S2713 is performed without performing S2711. Further, if only S2711 is performed without performing S2713, the size of the packet transmitted from the server 113 can be reduced.

(2-2) Change of MTU Next, a method of using the ICMP destination unreachable fragmented packet (see FIG. 30) will be described. In this method, the device is notified that the packet needs to be divided and fragmented, and the device sets the packet size based on the notification.

  FIG. 30 shows a format of an ICMP destination unreachable fragmented packet. As the MTU value set in each communication apparatus, the maximum transmission data size defined in the data link layer protocol used in the transmission line is normally set. However, when a communication device such as the PC 111 receives the ICMP destination unreachable fragmented packet, the MTU value set in the transmission packet by the PC 111 is overwritten by the MTU value included in the MTU field (2933). When the MTU value of the communication device is changed, the size of the IP packet transmitted by the communication device thereafter becomes equal to or smaller than the changed MTU value.

  A procedure for reducing the MTU of the low-priority communication apparatus using the ICMP destination unreachable fragmentation packet will be described with reference to FIGS. 30 and 31. FIG. First, the PC 111 transmits a 1500-byte data packet 2801 according to a normal MTU value 1500. As the route is changed as described above, the first IP telephone 114 of the present invention receives this packet from the PC 111. The adjustment unit 126 of the QoS control unit of the first IP telephone 114 obtains information (data of at least 64 bytes from the beginning of the received packet) to be set in the part 2934 of the fragmented packet requiring ICMP destination unreachable in FIG. (S2811). The received data is transferred as it is to the server 113 as a data packet 2802.

  Next, the adjustment unit 126 of the QoS control unit of the first IP telephone 114 generates an ICMP destination unreachable fragmented packet 2803 and transmits it to the PC 111 (S2812). The IP address of the first router 112 is set as the transmission source IP address of the IP header 2931 of this ICMP destination unreachable fragmented packet, and the IP address of the PC 111 is set as the destination IP address. In the ICMP header 2932, a predetermined value is set to indicate that this packet is a destination unreachable fragmented packet. Also, as the MTU value, for example, “576” is set as the packet size transmitted by the low priority communication apparatus. Furthermore, the received packet information acquired in S <b> 2811 may be set in a part 2934 of the received packet.

  Next, the PC 111 that has received the ICMP destination unreachable fragmentation packet 2803 changes its own MTU value to the designated 576 (S2813). Thereafter, the maximum size of the data packet 2804 transmitted by the PC 111 is 576 bytes. Thereby, the size of the data packet of the PC 111 transferred by the first IP telephone is reduced, and the QoS of IP telephone communication can be improved.

  Note that although 576 is specified as the MTU value here, any value may be used as long as it can secure the QoS of IP telephone communication. However, depending on the implementation of the low-priority communication device, there are many implementations that do not change the MTU value even if an ICMP destination unreachable fragmented packet with an MTU value less than 576 is specified, so it is better to specify 576 or higher. The effect is more certain.

  So far, the method using the ICMP destination unreachable fragmented packet used in the IPv4 network has been described. However, in the case of the IPv6 network, the ICMPv6 packet excessive packet has the same function, and therefore the MTU of the low priority communication apparatus can be changed by using this packet. The same effect can be obtained by specifying the MTU option in the ICMPv6 router notification packet.

  For example, it is assumed that the PC 111 transmits a packet with a fragment prohibition flag that prohibits packet division. In this case, the first IP telephone set 114 that has received this packet cannot divide the received packet due to the fragment prohibition flag. However, as described above, the first IP telephone 114 can change the MTU value of the PC 111 by sending the ICMP destination unreachable fragmentation packet. Therefore, even when a device that receives a packet cannot divide the received packet, the size of the packet can be reduced.

  Further, since the change in the MSS in (2-1) is performed by changing the MSS option in the TCP header, it cannot be used for UDP. However, the method (2-2) for changing the MTU value described above can be applied to both TCP and UDP.

<Others>
Note that <applied environment>, <installation position>, <route change method>, and <at the timing of route change> are the same as those in the first embodiment, and thus are omitted.

  By using the communication device of the present invention that performs the above operation, low priority communication and high priority communication compete, but priority is not replaced without replacing routers in networks where priority control is not performed. The control function can be realized, and the user can easily enjoy real-time communication such as an IP phone without changing the provider.

  The communication device of the present invention further includes a transmission data generation unit that generates transmission data to be transmitted to the counterpart communication device, and when the transmission data is high priority communication data, the selection unit prioritizes the transmission data. It is also possible to select to transmit automatically. Thus, when the communication device itself transmits high-priority transmission data to another communication device, it transmits the high-priority transmission data with priority over the low-priority communication data that needs to be relayed. be able to. In addition, the above-described selection unit may select so as to preferentially transmit high priority communication data among a plurality of received data to be received. Thus, when the communication device receives a plurality of received data from a plurality of communication devices and needs to relay to other communication devices, the received data with the highest priority among these received data is given priority. Can be sent.

(Other embodiment examples)
Each embodiment described in the present invention can also be realized by causing the CPU to execute a program for causing the CPU to execute the above-described processing procedure. In this case, the program may be stored in a recording medium and executed from a storage device (such as a hard disk) of the device that stores the contents, or may be directly executed from the recording medium. The recording medium here refers to a recording medium such as a semiconductor memory such as a ROM, a RAM, or a flash memory, a magnetic disk memory such as a flexible disk or a hard disk, an optical disk such as a CD-ROM, DVD, or BD, or a memory card.

  The functions of the QOS control unit described in each embodiment may be realized as an LSI that is an integrated circuit. The name used here is LSI, but it may also be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

  Further, the method of circuit integration is not limited to LSI, and implementation with a dedicated circuit or a general-purpose processor is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI, or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

  The communication device of the present invention according to the present invention can be applied to a general network in which priority control is not performed, although low priority communication and high priority communication compete. For example, when multiple communications are competing on an access line (such as an ADSL line) in a home Internet connection environment, or a low-speed communication path (such as a wireless section or a power line) in a home LAN or corporate LAN. Applicable.

  The present invention relates to a communication device capable of QoS control, a storage medium, an integrated circuit, and a communication system.

  In recent years, broadband Internet connections have been used in many workplaces and homes. FIG. 32 shows a typical Internet connection configuration in the current home. The user contracts with a first ISP (Internet Service Provider) 3 and installs the first router 12 purchased (or rented from the ISP) in the first home 1. Then, the first router 12 is connected to a device to be connected to the Internet 2 such as a PC (Personal Computer) 11.

  In this environment, when the PC 11 communicates with the server 13 disclosed on the Internet, the PC 11 passes through the first router 12, the access line 6, the first ISP 3, the Internet 2, and the like. Currently, ADSL lines (downstream: about 1 Mbps to 50 Mbps, upstream: about 512 Kbps to about 5 Mbps (see Non-Patent Document 1)) are widely used as access lines. Further, Ethernet (registered trademark) (bidirectional 100 Mbps) is generally used as a transmission medium in a home LAN. The first router 12 described herein may include an ADSL modem function on the Internet side and a hub function on the LAN (in-home) side as necessary. To do.

  In addition, applications that perform real-time communication using IP (Internet Protocol) used on the Internet, such as IP phones and IP videophones, have been widespread in recent years. For example, IP Centrex and IP telephone systems are used in companies, and IP telephones using broadband Internet connection such as ADSL and optical fiber are used in homes.

  However, since IP basically does not have a function of guaranteeing quality, if real-time communication is performed, if the communication band is not sufficient or is affected by other communications, the quality of service (QoS: Quality of Service) ) May be reduced.

  For example, when considering FIG. 33 as an example in which an IP telephone is simply connected to the environment shown in FIG. 32, there is a risk that QoS will decrease. Below, the mechanism is demonstrated.

  In FIG. 33, the first IP telephone 14 is connected to the LAN side of the first router 12. In this configuration, when communication is performed between the first IP telephone 14 and the second IP telephone 17 existing in another second home 4, the first router 12, the first ISP 3, the Internet 2, and the second home 4 side side are connected. 2 ISP 5 and the second router 16 are routed.

  Here, considering the case where the IP telephone communication 32 is performed simultaneously with the PC-server communication 31 in the environment as shown in FIG. 33, both communications go through the first router 12 and the first ISP 3. In the following, the processing of the first router 12 at this time will be described, and it will be described that the QoS of the IP phone is lowered due to a phenomenon occurring there.

  FIG. 34 schematically shows the detailed structure inside the first router 12 in FIG. 33 (particularly, only the part related to data transfer from the LAN side to the access line side). The configuration outside the first home 1 in FIG. 34 is the same as that in FIG.

  First, the operation when only the communication 32 between the IP phone and the IP phone exists will be described. First, the first IP telephone 14 sends voice data as an IP packet to the LAN line 7. Next, when receiving this packet, the first router 12 temporarily stores data in the reception buffer 21. Then, the transmission processing unit 22 processes the data at the head of the reception buffer 21 and sends it to the access line 6. The transmission amount of the voice data transmitted from the first IP telephone 14 is about 64 Kbps (in the case of ITU-T G.711), which is less than twice the protocol overhead in the lower layer. Therefore, since the ADSL uplink line speed (512 Kbps ~) is not reached, a large amount of data is not stored in the reception buffer 21, and the received data can be immediately sent to the access line 6. For this reason, QoS of IP telephone communication is ensured.

Next, consider the processing of the first router 12 when the communication 31 between the PC and the server 31 is simultaneously performed in addition to the communication 32 between the IP phone and the IP phone. For example, if the communication 31 between the PC and the server is file transfer, the PC 11 transmits a large amount of data to the LAN line 7 at a stroke in order to transfer the file as fast as possible. The transfer speed (100 Mbps) of the LAN line 7 is very high compared to the upstream line speed (up to about 5 Mbps) of ADSL. Therefore, a large amount of data is accumulated at once in the reception buffer 21 of the first router 12. The transmission processing unit 22 sends the data stored in the reception buffer 21 to the access line 6 in order from the data existing at the head. Under such circumstances, the following phenomena such as (Phenomenon 1) to (Phenomenon 3) occur. (Phenomenon 1) After the IP telephone communication data is stored in the reception buffer 21, the access line 6 The delay time until the data is sent to is increased.

  (Phenomenon 2) When data of IP telephone communication is stored in the reception buffer 21, how much data is stored in the reception buffer 21 differs depending on the timing, and as a result, delay time fluctuation (jitter) occurs.

  (Phenomenon 3) When the IP telephone communication data arrives at the first router 12, if the reception buffer 21 is not empty, the arrived IP telephone communication data is discarded and data loss occurs.

  If the above phenomenon occurs, the arrival of data will not be in time for the normal playback of audio on the receiving side, and the audio will be interrupted or the sound quality will deteriorate.

  Therefore, Non-Patent Document 2 discloses a home IP telephone service in a configuration that makes it possible to prevent a decrease in QoS of IP telephone communication due to the occurrence of the above phenomenon. FIG. 35 shows a configuration in which the analog telephone 70 and the dedicated router 60 are connected via the analog line 73 using the dedicated router 60 together with the function (such as the voice data conversion unit 22) as an IP telephone. In the case of such a configuration, the dedicated router 60 can improve the QoS of the IP phone by performing the following processing.

First, analog data from the analog telephone 70 is converted by the voice data converter 25 and used as voice data for IP telephone communication. Here, the file transfer data from the PC 11 is stored in the reception buffer 23, and the voice data for IP telephone communication converted by the voice data conversion unit 25 is stored in the voice data buffer 24. Next, when audio data is stored in the audio data buffer unit 24, the transmission processing unit 22 preferentially transmits the data to the access line 6 that is an ADSL uplink. On the other hand, the transmission processing unit 22 transmits the file transfer data stored in the reception buffer 23 to the access line 6 only when the audio data is not stored in the audio data buffer 24. In this way, the audio data is not waited for a long time in the audio data buffer 24, and the audio data is not lost. In this way, the QoS of IP telephone communication can be improved.

  However, even when the above control is performed, the QoS of IP telephone communication may be lowered due to the occurrence of phenomenon 4 below.

  (Phenomenon 4) When a voice data packet for IP telephone communication arrives at the voice data buffer 24 while the file transfer data is being transmitted to the access line, the voice data packet is transmitted until the file transfer data transmission is completed. Absent. As a result, audio data delay and delay fluctuation occur.

  Hereinafter, phenomenon 4 will be described in detail with reference to FIGS. 35 and 36. FIG. FIG. 36 is an explanatory diagram for explaining a data transmission period from the router. FIG. 36 illustrates the arrival timing of file transfer data to the router, the timing of voice data generation, and the transmission period of each data to the access line 6, and the horizontal axis represents time. First, consider a state in which audio data is not accumulated in the audio data buffer 24 and only file transfer data is accumulated in the reception buffer 23. This state occurs, for example, when the arrival of the file transfer data 2501 in FIG. 36 occurs in a state where there is no data in the respective buffers 23 and 24. According to the above control, first, file transfer data arriving at the buffer 23 first starts to be transmitted to the access line 6. As shown in FIG. 36, it is assumed that the first audio data 2502 is generated before the transmission of the file transfer data is completed. The first audio data remains stored in the audio data buffer 24 until the file transfer data is completely sent to the access line 6. Therefore, a waiting time 2511 for the first audio data occurs. This waiting time is a maximum value calculated by “time required for file transfer data transmission = file transfer data packet size (bit) / access line speed”. This waiting time causes delay time and delay time fluctuation (jitter), and lowers the QoS of IP telephone communication.

Note that file transfer data is generally TCP (Transmission Control).
ol Protocol), the packet size is often about 1500 bytes per packet. For example, if the speed of the access line is 512 Kbps, the time taken to transmit one packet is about 23 milliseconds. Non-Patent Document 3 describes the IP telephone quality standards prescribed by the Ministry of Internal Affairs and Communications. Among them, the end-to-end delay is 100 milliseconds or less as a class A standard that calls quality is comparable to fixed telephones. Therefore, it can be said that the above-mentioned delay of 23 milliseconds leads to a decrease in QoS of IP telephone communication.

  In order to reduce the waiting time of voice communication data due to such phenomenon 4 and improve the QoS, for example, in Patent Document 1, a router device (transfers voice data and PC communication data to an external network such as the Internet). 35, which corresponds to the dedicated router 60 in FIG. 35) performs IP fragmentation (fragmentation) before transferring communication data from the PC to the access line. Thus, by fragmenting file transfer data, the packet size is reduced. Therefore, by interposing the audio data between the file transfer data and the file transfer data having a reduced packet size, the waiting time of the audio data can be reduced.

Patent Document 2 discloses a method for preliminarily securing network resources such as bandwidth before starting communication in order to realize QoS control of real-time communication such as IP telephone communication. As a result, it is possible to prevent the QoS degradation of the real-time communication due to the phenomenon 1 to the phenomenon 3. In Patent Document 2, each router that relays real-time communication has a bandwidth management table for managing the correspondence between each flow passing through the router and the bandwidth allocated to each flow, and bandwidth control is performed based on the bandwidth management table. I do. Here, each flow includes an arbitrary flow including real-time communication and non-real-time communication, and each flow is identified by the source address and destination address of the IP header. A separate server device for centrally managing the bandwidth management table of each router exists, and the server device sets the bandwidth management table of each router in response to a request from a communication device that performs real-time communication.
JP 2001-53805 A JP 2003-60691 A Service list of ADSL line provider e-access <http: // www. eacess. net / service / 47mir / index. html>, search date September 10, 2004 IP phone service Yahoo! Connection configuration diagram when using BB service <http: // bbpromo. yahoo. co. jp / promotion / service / bbphone / simple_guide.jp / promotion / service / bbphone / simple_guide. html>, search date September 10, 2004 Report on “Research Group on IP Network Technology” <http: // www. soumu. go. jp / s-news / 2002 / 020222_3. html>, search date January 13, 2005

  However, when the IP telephone service in Non-Patent Document 2 is used or the method described in Patent Document 1 is used to prevent QoS degradation, the output of the analog telephone 70 is input, It is necessary to control by a dedicated router having the fragment function described in 1, and the degree of freedom of the user is low due to the configuration of the installation of the dedicated router. Furthermore, in order to use the IP telephone service described in Non-Patent Document 2, it is necessary to subscribe to a specific ISP and purchase a dedicated router 60 or rent a monthly fee. Therefore, for users who have subscribed to an ISP that cannot use the IP phone service and used the Internet connection in the configuration shown in FIG. 32, in order to use the IP phone, the initial cost when switching the ISP and the replacement of the router There is a problem that costs are incurred. In addition, by switching ISPs, problems such as the inability to receive services provided only by ISPs that have been previously subscribed, such as hosting services and virus check services, and changes in e-mail addresses also occur.

  In order to apply the method for realizing the QoS control described in Patent Document 2, it is necessary to operate cooperatively as a system including routers on the Internet, routers in the home, and IP telephones. Therefore, it is impractical to make such a system change in order to use an IP telephone at home.

  Therefore, an object of the present invention is to provide a communication apparatus and a communication system capable of QoS control.

  In order to solve the above-described problem, claim 1 of the present application is one of communication apparatuses that perform communication via a network in which a plurality of communications with different priorities is performed, and communication that controls communication according to the priorities. A priority information holding means for holding priority information relating to the priority of each communication, and first control data for changing a communication path of low priority communication based on the priority information; And a path change control means for transmitting the first control data to a low priority communication apparatus that performs the low priority communication or a relay apparatus that relays the low priority communication performed between other communication apparatuses via the network. And a communication device characterized by comprising:

  A low-priority communication apparatus that performs low-priority communication is a first control for changing a communication path of low-priority communication from a communication apparatus that controls communication according to priority (hereinafter, communication apparatus that performs priority control). Data is received and the communication path is changed based on the first control data. Therefore, when high-priority communication and low-priority communication are congested, the high-priority communication path can be preferentially secured by changing the low-priority communication path. . As described above, the communication device that performs priority control can control communication according to the priority in addition to the communication function. Therefore, by connecting a communication device that performs the above-described priority control to a home LAN that does not perform communication control according to priority, communication is performed via the network using the communication device that performs priority control. However, QoS for high priority communication can be ensured. Therefore, in order to ensure QoS, it is not necessary to provide a separate dedicated router that controls communication according to priority. Therefore, the user does not need to change the existing router or system configuration, and can subscribe to an arbitrary provider and perform real-time communication such as an IP phone with high quality. Further, the QoS of the high-priority communication device can be changed without changing the entire system including the low-priority communication device, the high-priority communication device, and the relay device by simply providing a communication device that performs priority control capable of ensuring QoS. Can be secured.

  As a high-priority communication apparatus that performs high-priority communication, for example, an IP telephone or the like that requires real-time performance such as telephone communication can be cited. Moreover, as a low priority communication apparatus, the terminal etc. which perform a file transfer etc. are mentioned, for example. Therefore, real-time performance can be maintained by securing the QoS of the IP telephone using a communication device that performs priority control.

  In addition, when transmitting 1st control data to a low priority communication apparatus, the communication path from a low priority communication apparatus to the other party's communication apparatus can be changed. Further, when the first control data is transmitted to the relay device, the communication path from the counterpart communication device to the low priority communication device can be changed.

  A second invention of the present application is the communication according to the first invention, wherein the route change control means changes the destination of the communication route of the low priority communication to an untransmittable address in the first control data. Providing equipment.

  By changing the destination of the communication path of the low priority communication to an address that cannot be transmitted, the low priority communication device transmits the transmission data to an address that cannot be transmitted. Therefore, since transmission data transmitted from the low priority communication device is discarded, a communication path for performing high priority communication is established even when communication of high priority communication and communication of low priority communication are congested. Priority can be secured.

  A third invention of the present application is the communication device according to the first invention, wherein the path change control means controls communication of a destination of a communication path of the low priority communication included in the first control data according to the priority. The communication apparatus further includes communication control means for controlling the output of transmission data from the low priority communication apparatus to the network.

  By changing the destination of the communication path of the low priority communication to the communication device that performs the priority control, the transmission data from the low priority communication device is transmitted to the communication device that performs the priority control. Then, the communication device that performs priority control adjusts, for example, to limit the output of transmission data from the low priority communication device to the network. Thereby, even if the communication of high priority communication and the communication of low priority communication are congested, the communication path of high priority communication can be secured preferentially.

  According to a fourth invention of the present application, in the third invention, the communication control means determines whether or not the transmission destination of at least one received data is its own device, and the received data is low priority communication from the low priority device. Analyzing means for analyzing whether or not the data is high-priority communication data is preferentially selected over low-priority communication data whose destination is other than the own device according to the analysis result by the analyzing means. And a selecting means for controlling to transmit to the transmission destination.

  Note that it is possible to determine whether or not relaying is necessary based on whether or not the destination of the received data is its own device. By these analysis means and selection means, it is possible to preferentially secure a communication path for high priority communication even when high priority communication and low priority communication are congested.

  Here, it further includes a transmission data generation unit that generates transmission data to be transmitted to the counterpart communication device, and when the transmission data is high-priority communication data, the selection unit preferentially transmits the transmission data. select. Thus, when the communication device itself transmits high-priority transmission data to another communication device, it transmits the high-priority transmission data with priority over the low-priority communication data that needs to be relayed. be able to. In addition, the selection means selects so as to preferentially transmit high priority communication data from among a plurality of received data to be received. As a result, when the communication device receives a plurality of received data from a plurality of communication devices and needs to relay to another communication device, the received data with the highest priority among these received data is preferentially transmitted. can do.

  The fifth invention of the present application is the fourth invention, wherein, as a result of the analysis by the analyzing means, the communication control means sets the source address of low priority communication data whose destination is other than the own apparatus as the address of the own apparatus. The adjusting unit further includes an adjusting unit that performs an address rewriting process for rewriting the destination address of the low priority communication data to the original destination address of the low priority communication data transmitted from the low priority communication device before the path change. Provides a low-priority communication data after the address rewriting process to the selection means.

  It operates as a network device that performs relay and loopback by rewriting the address, and can appropriately relay and loopback traffic.

  A sixth invention of the present application further includes an upper layer processing unit for processing received data whose destination is the own apparatus as a result of analysis by the analyzing means in the fourth invention, wherein the analyzing means has a destination of the received data Whether the device is the device itself is determined by analyzing the IP header of the received data based on whether the destination is the IP address of the device itself. If the destination of the received data is the device itself, the higher layer processing unit The communication apparatus according to claim 4, wherein the reception data is transmitted to the selection unit and the reception data is transmitted to the selection unit when the destination is other than the own apparatus.

  Relay and loopback can be performed by analyzing at the IP level a frame that is to be detoured at the Ethernet (registered trademark) level. In addition, since the priority control device does not perform any processing including interrupt processing for frames addressed to other devices, it eliminates the need for extra processing related to communication.

  A seventh invention of the present application provides the communication device according to the third invention, wherein the communication control means is realized by hardware.

  Processing for relaying frames addressed to other devices and processing related to priority control can be performed by hardware, and priority control is performed without using an expensive CPU as long as the CPU is capable of transmitting and receiving the local terminal application. be able to.

  According to an eighth invention of the present application, in the fourth invention, the communication control means further includes an adjustment means for discarding a part or all of the low priority communication data, and the adjustment means is partially or entirely discarded. The communication apparatus is characterized in that the low priority communication data is transmitted to the selection means.

  Even if the communication means of the communication device that performs priority control discards the transmission data from the low-priority communication device, the communication of the high-priority communication and the communication of the low-priority communication are congested. A communication path for performing communication every time can be preferentially secured.

  A ninth invention of the present application is the fourth invention, wherein the communication control means further includes an adjustment means for performing a first adjustment process for adjusting a communication rate of the low-priority communication, A communication apparatus is provided, wherein low-priority communication data after one adjustment process is transmitted to the selection means.

  By adjusting the transmission rate of the transmission data received from the low-priority communication device, the transmission rate from the counterpart communication device of the low-priority communication device and the transmission rate from the counterpart to the low-priority communication device are adjusted. be able to. Therefore, when high-priority communication and low-priority communication communication are congested, the amount of transmission from the low-priority communication device to the partner or the destination can be reduced by adjusting the transmission rate to be lower. It is possible to reduce the amount of transmission from the priority communication device and preferentially secure a communication path for performing high priority communication.

  A tenth invention of the present application provides the communication apparatus according to the ninth invention, wherein the adjusting means adjusts a transmission rate by adjusting a value of a window field of a TCP header.

  By adjusting the TCP flow control of the low priority communication device, it is possible to preferentially secure a communication path for performing high priority communication.

  The eleventh invention of the present application is the ninth invention, further comprising storage means for storing the low priority communication data, wherein the adjustment means is configured such that the low priority communication data is a TCP data packet or a TCP ACK packet. In such a case, the communication apparatus is characterized in that the low-priority communication data is accumulated for a certain period of time using the accumulating unit and then transferred to the selecting unit.

  By adjusting the TCP flow control of the low priority communication device, it is possible to preferentially secure a communication path for performing high priority communication.

  The twelfth invention of the present application is the fourth invention, wherein the communication control means further comprises an adjusting means for dividing the transmission data from the low priority communication device into a plurality of data using a first dividing method, The adjustment unit provides a communication apparatus, wherein the data divided into a plurality of pieces using the first division method is transmitted to the selection unit.

  The adjustment means of the communication device that performs the priority control divides the transmission data from the low priority communication device so that the data of the high priority communication that arrives during the data transfer of the low priority communication is waited for a long time. Can be prevented. Therefore, QoS of high priority communication can be improved.

  A thirteenth invention of the present application provides the communication apparatus according to the twelfth invention, wherein the first dividing method divides into IP fragments.

  Since the IP fragment reception function is a function that a normal IP communication apparatus has, it is possible to improve the QoS of high priority communication without requiring a special function from another apparatus.

  In a fourteenth aspect of the present invention, in the fourth aspect, the communication control means communicates with the other party of the low priority communication device from the low priority communication device based on communication data received from the low priority communication device. Generating the third control data for controlling the size of the communication data to the device or the communication data from the communication device of the counterpart of the low priority communication device to the low priority communication device, and the low priority communication There is further provided a communication device further comprising adjusting means for transmitting to the device or the communication device of the other party.

  The adjusting means controls the size of communication data from the low priority communication device to the counterpart communication device based on communication data received from the counterpart communication device of the low priority communication device. Fourth control data may be generated and transmitted to the low priority communication device.

  In this way, by adjusting the transmission rate from the low-priority communication device to the counterpart communication device and the transmission data size from the counterpart to the low-priority communication device, the data transmission of low-priority communication is being performed in the communication device. Therefore, it is possible to prevent the data of high priority communication arriving at the terminal from waiting for a long time, and to improve the QoS of high priority communication.

  In a fifteenth aspect of the present invention, in the fourteenth aspect, the third control data is a TCP SYN packet, and the adjustment unit generates a SYN packet in which the MSS value included in the received SYN packet is changed to a desired value. A communication device is provided.

  The size of transmission data can be reduced by changing the MSS value. Such an MSS adjustment function by the MSS option in the SYN packet is a function that a normal IP communication apparatus has. Therefore, QoS of high priority communication can be improved without requiring a special function from another device.

  According to a sixteenth aspect of the present invention, in the fourteenth aspect, the third control data is an ICMP destination unreachable fragmented packet, and the adjusting means includes data included in a packet transmitted from a low-priority communication device before An ICMP destination unreachable fragmentation packet including a part of the packet and including a desired MTU value is generated.

  The low-priority communication device that has received the destination unreachable fragmented packet determines the subsequent packet size based on the MTU value included in the received packet. By changing the MTU value of the low-priority communication device by the adjusting means of the high-priority communication device, the size of the transmission data from the low-priority communication device can be reduced. Since the MTU adjustment function when such an ICMP destination unreachable fragmented packet is received is a function that a normal IP communication device has, it has high priority without requiring a special function from other devices. Can be improved.

  A seventeenth invention of the present application is the first invention, wherein the route change control means changes a destination of the communication route of the low priority communication to the address of the own device in the first control data, and the priority Generating second control data for changing the communication path of the high priority communication based on the information, and changing the destination of the communication path of the high priority communication in the second control data to the address of the own device The communication apparatus is characterized in that the second control data is transmitted to the high priority communication apparatus.

  A communication device that performs priority control can accurately grasp the congestion state of high-priority communication and low-priority communication by receiving communication from not only low-priority communication devices but also high-priority communication devices. . Then, based on the grasped congestion state and priority information, when there is congestion, the data from the high priority communication device is output to the network with priority over the data from the low priority communication device. Therefore, a communication path for high priority communication can be secured with priority.

  In an eighteenth aspect of the present invention, in the first aspect, the first control data transmitted by the path change control means is any one of an ARP request packet, an ARP response packet, an ICMP path change packet, and an ICMPv6 neighbor search packet. A communication device is provided.

  The mechanism of the ARP request and the ARP response is implemented in almost many IP-compatible devices. Therefore, the first control data for changing the communication path of the low priority communication can be generated using the existing ARP request and ARP response. Similarly, the ICMP path change mechanism is also implemented in almost all IP-compatible devices. Also, the mechanism of ICMPv6 neighbor discovery packet is implemented in many IPv6 devices. Therefore, when the communication of high priority communication and communication of low priority communication are congested using the existing mechanism, the communication path of high priority communication can be secured with priority.

  The nineteenth invention of the present application further includes detection means for detecting whether or not communication via the network by the high priority communication device is performed in the first invention, wherein the route change control means is the high priority communication. Provided is a communication device characterized in that the first control data is transmitted to the low priority communication device or the relay device only when communication is performed by the device.

  By changing the communication path for low-priority communication according to the presence or absence of high-priority communication, the communication path for high-priority communication can be secured only during the required period, and to low-priority communication during other periods The influence of can be eliminated.

  The twentieth invention of the present application further comprises a QoS value holding means for holding a QoS value set to hold the quality of high priority communication in the nineteenth invention, wherein the detection means further A value indicating quality is calculated, the calculated quality value is compared with the QoS value, and when the calculated quality value is smaller than the QoS value, the path change control means includes: The communication apparatus is characterized in that the first control data is transmitted to the low priority communication apparatus or the relay apparatus.

  By changing the communication path for low-priority communication according to the deterioration of the quality of high-priority communication, it is possible to secure the communication path for high-priority communication only during the required period, and low priority during other periods. The influence on communication can be eliminated.

  A twenty-first invention of the present application is a computer-readable recording medium on which a priority control program executed by a control device that controls communication according to the priority is recorded in a plurality of communications performed via a network. And priority information holding means for holding priority information related to the priority of each communication, and based on the priority information, generate first control data for changing the communication path of the low priority communication, A computer as a path change control means for transmitting the first control data to a low-priority communication device that performs the low-priority communication or a relay device that relays low-priority communication performed between other communication devices via the network A computer-readable recording medium is provided, in which a priority control program for functioning is recorded. By using the recording medium in which the priority control program is described, the same function and effect as the first invention of the present application are obtained.

  The 22nd invention of the present application is an integrated circuit that controls communication according to the priority in a network in which a plurality of communications with different priorities are performed, and priority information that holds priority information about the priority of each communication Based on the holding means and the priority information, the first control data for changing the communication path of the low priority communication is generated, and the low priority communication apparatus or the network that performs the low priority communication is used. There is provided an integrated circuit comprising: path change control means for transmitting the first control data to a relay apparatus that relays low priority communication performed between other communication apparatuses. The integrated circuit has the same effects as the first invention of the present application.

  A twenty-third invention of the present application is a communication device that controls communication according to priority in a communication system in which a communication device that controls communication according to communication priority and a plurality of communication devices with different priorities are connected. Includes priority information holding means for holding priority information related to the priority of each communication, and first control data for changing a communication path of low priority communication with low priority based on the priority information. Route change control for generating and transmitting the first control data to a low priority communication device that performs the low priority communication or a relay device that relays low priority communication performed between other communication devices via the network A low-priority communication device or a relay device that relays low-priority communication performed between other communication devices via the network, the communication device controlling communication according to the priority Receive al the first control data, and changes the communication path of the low-priority communication, to provide a communication system. The said communication system has the same effect as 1st invention of this application.

  According to the present invention, by changing the communication path of low-priority communication, it is possible to perform control to give priority to high-priority communication that requires high QoS, such as real-time communication, and to ensure the communication quality. .

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a network configuration diagram according to the first embodiment. In FIG. 1, communication devices such as a PC 111 and a first IP telephone 114 are connected to the LAN side of a first router 112 existing in the first home 101 to form a home LAN. The home LAN is connected to the Internet 102 via the access line 106 and the first ISP 103. The second router 116 is also present in another second home 104, and a second IP telephone 117 is connected to the LAN side. The home LAN of the second home 104 is connected to the Internet 102 via the second ISP 105.

  In FIG. 1, file transfer 131 (hereinafter referred to as PC-server communication 131) is transferred between the PC 111 in the first home 101 and the server 113 on the Internet 102, and the first IP telephone 114 in the first home 101. IP telephone communication 132 (hereinafter referred to as IP telephone-IP telephone communication 132) using the Internet 102 is performed with the second IP telephone 117 in the second home 104. Here, the communication 132 between the IP phone and the IP phone is a communication that requires real-time property, and is a high priority communication with a high priority. On the other hand, the communication 131 between the PC and the server is a low priority communication with a low priority. The first IP telephone 114 is a high priority communication device, and the PC 111 is a low priority communication device.

  In FIG. 1, a QoS control unit 621 is provided as a function unit of the first IP telephone 114, and QoS is controlled by the QoS control unit 621.

  Further, the internal configuration of the first IP telephone 114 and the QoS control unit 621 in FIG. 1 will be described in more detail with reference to FIG. FIG. 2 is an internal configuration diagram in the first IP telephone 114 and the QoS control unit 621. As shown in FIG. 2, the QoS control unit 621 includes a priority information holding unit 841 and a path change control unit 842. The priority information holding unit 841 holds priority information related to communication priority. The priority information is information for distinguishing which communication is a communication with a high priority. The route change control unit 842 generates route change control data for changing the communication route of the low priority communication, and is performed between the other communication devices via the PC 111 or the network that performs the low priority communication. The route change control data is transmitted to a relay device that relays communication. Further, the route change control unit 842 can receive data from the LAN line 107 and transmit data to the LAN line 107 via the communication processing unit 123 in the first IP telephone 114. The IP telephone application 122 in the first IP telephone 114 receives voice input from the user, generates voice data for IP telephone communication, and connects the LAN line 107 via the TCP / IP processing unit 124 and the communication processing unit 123. To send to.

Hereinafter, the first IP telephone 114, which is the communication apparatus of the first embodiment, interrupts the low priority communication by changing the path of the low priority communication (PC-server communication 131 in FIG. 1), A procedure for ensuring QoS for priority communication (IP telephone-IP telephone communication 132 in FIG. 1) will be described.

  First, the outline of the QoS control process will be described by explaining the overall flow of the QoS control process, and then the detailed procedure of the QoS control process will be explained.

<Overall flow of QoS control processing>
The QoS control process in the first embodiment of the present invention is roughly performed in the following procedure.

First, as a state before the QoS control process is performed, it is assumed that only low priority communication (PC-server communication 131) is performed in the network of FIG. Thereafter, when high-priority communication (IP telephone-IP telephone communication 132) is started, the QoS control unit 621 performs the following control. Hereinafter, a description will be given with reference to FIG.

(1) Procedure 1
The priority information holding unit 841 holds priority information for distinguishing between low priority communication and high priority communication, and notifies this to the route change control unit 842 (S851). Here, the first IP telephone 114 is set as a high priority communication apparatus that performs high priority communication, and the PC 111 is set as a low priority communication apparatus that performs low priority communication.

(2) Procedure 2
The route change control unit 842 obtains information such as an IP address necessary for generating route change control data for route change (S852). Note that information acquired by the route change control unit 842 differs depending on the route change method.

  The route change control unit 842 generates route change control data for route change from the information acquired here and the information obtained by the procedure 1, and terminates low priority communication that is a device to be controlled for route change. The route change control data is transmitted to the PC 111 (S853).

  The communication processing unit 123 sends this route change control data to the LAN line 107. The route change control data includes information on the destination after the change of the data output from the PC 111 which is a low priority communication device. In this embodiment, an address that does not exist in the LAN, such as an IP address or a MAC address, is designated as the destination after the change.

(3) Procedure 3
The PC 111 that is a low-priority communication device and a device to be controlled receives the route change control data, and changes the communication route of subsequent low-priority communication data.

(4) Procedure 4
When the communication path is changed according to the procedure 3, the PC 111 transmits data to an address that does not exist. Thereby, the low priority communication is interrupted until the communication path returns to the original state by some processing. That is, data from the PC 111 generated in the PC-server communication 131 that is low priority communication is transmitted to other than the first router 112, and the low priority communication is interrupted. Therefore, the first router 112 receives only the voice data from the first IP telephone 114 generated in the IP telephone-IP telephone communication 132 which is high priority communication. Therefore, the first router 112 is not congested with high priority communication and low priority communication. In this way, when high-priority communication and low-priority communication are congested, the communication path for low-priority communication is changed to preferentially secure the communication path for high-priority communication. QoS can be secured. By connecting a communication device having such a QoS control processing function to a home LAN or the like where communication control according to priority is not performed, a network is configured using the communication device having the QoS control function. The QoS of the high priority communication can be ensured while performing the communication via the network. Therefore, in order to ensure QoS, it is not necessary to provide a separate dedicated router for controlling communication according to priority. Therefore, the user does not need to change the existing router or system configuration, and can subscribe to an arbitrary provider and perform real-time communication such as an IP phone with high quality. Further, by providing only the first IP telephone 114 capable of ensuring QoS, QoS of high priority communication can be ensured without changing the entire system including the PC 111 and the router which are low priority communication devices.

  Note that low-priority communication does not necessarily have to be started before the execution of this procedure. Even if low-priority communication is started after the start of high-priority communication, low-priority communication is not It is interrupted and QoS of high priority communication can be secured.

<Detailed procedure of QoS control process>
Next, a detailed procedure when the above procedure is performed will be described below for Procedure 1 to Procedure 4 in <Overall Flow of QoS Control Processing>. Although there are several methods for changing the route, it is assumed here that an ARP request (request) is used. This method can be used only when the communication processing unit 123 operates according to the Ethernet (registered trademark) protocol.

  First, ARP (Address Resolution Protocol) will be described in order to understand the procedure described below. ARP is a protocol for notifying each other between devices communicating within a LAN about the correspondence between IP addresses and MAC addresses (addresses unique to network I / F hardware) in Ethernet (registered trademark). When performing IP communication over Ethernet (registered trademark), each device normally sends an ARP request (specifying the IP address of the communication partner) as a broadcast Ethernet (registered trademark) frame once every five minutes and receives it. When the designated IP address is its own, each device returns an ARP response as a unicast Ethernet (registered trademark) frame.

  FIG. 3 is a protocol format of an ARP request and an ARP response defined in RFC826. The field 911 does not show details here, but includes various fields such as a field indicating whether this data is an ARP request or an ARP response. Further, the ARP request and the ARP response include a source MAC address 912 and a source IP address 913 related to the source communication device, and information of a destination MAC address 914 and a destination IP address 915 related to the destination communication device. ing. Therefore, by receiving the ARP request or the ARP response, it is possible to know the MAC address for each other's IP address. The correspondence relationship between the IP address and the MAC address exchanged by communicating with each other is managed in the ARP table possessed by each communication device. Then, at the time of packet transmission, each communication device searches the ARP table using the destination IP address of the packet to be transmitted as a key, and determines the destination MAC address of the frame to be transmitted. Note that FCS (Frame Check Sequence) 916 is information added to check whether the Ethernet (registered trademark) frame is damaged.

  Hereinafter, the detailed procedure of the QoS control process when the ARP request is used will be described with reference to FIGS. 1 to 8 for each of the above (1) Procedure 1 to (4) Procedure 4. FIG. 4 is a schematic diagram showing the overall flow of data in the QoS control process when an ARP request is used, and shows how each piece of data 1061, 1062, and 1063 to be exchanged moves on the network. ing. FIG. 5 is an example of the overall process and data flow in the QoS control process when an ARP request is used. The time series of each data exchange in the QoS control process and the path change control data generation process in the first IP telephone 114 is shown. Show. FIG. 6 is an example of a route change control data generation process in the route change control unit when an ARP request is used, and FIGS. 7A to 7C are examples of the ARP table 1021 of the PC 11 that is the control target device. A state in which the ARP table 1021 is updated as needed. FIG. 8 is a list of IP addresses and MAC addresses of each device. The MAC addresses and IP addresses of the PC 111, the first router 112, the server 113, and the first IP telephone 114 are shown, and addresses that do not exist in the LAN are also fictitious. Defined as the address of the device 115.

(1) Procedure 1
The procedure 1 will be described with reference to FIG. First, in the present embodiment, the IP telephone communication performed by the first IP telephone 114 which is its own apparatus is a high priority communication, and all the communication from the LAN to the Internet 2 via the first router 112 is a low priority communication. Assuming communication, the QoS control unit 621 of the present invention operates. At this time, the priority information holding unit 841 in FIG. 2 has the IP_router value necessary for route change control by the ARP request as default information. Here, the IP_router is an IP address of the first router 112 that relays communication from the PC 111 and the first IP telephone 114 to the network 2 as shown in FIG. Note that this information is not predetermined information, and may be input from a user interface, or may be acquired by some procedure using a network.

  Next, the priority information holding unit 841 notifies the IP_router to the route change control unit 842 as information related to low priority communication (see S851 in FIG. 2). At the same time, in step S1302, which will be described later, IP_PC may be notified in order to check the IP address of the PC 111.

(2) Procedure 2
The procedure 2 and subsequent steps will be described with reference to FIGS.

  Step S1201: Next, the PC 111, which is a device in the LAN that terminates the low-priority communication, uses the IP address of the first router 112 that first passes to communicate with the server 113 as shown in S1201 of FIG. A broadcast ARP request 1061 is transmitted with a certain IP_router as the destination IP address 915. At this time, the ARP table of the PC 111 is the table 1171 of FIG. 7A.

  Thereafter, the route change control unit 842 in the QoS control unit performs the route change control data generation process in S1202. Details of this processing will be described with reference to the flowchart of FIG. 6, the data 1061 and 1062 of FIG. 5, and the block diagram of FIG. Further, the ARP request / response fields are as shown in FIG.

(Processing in S1202)
Step S1301: First, the route change control unit 842 receives the ARP request 1061 (1061 in FIG. 5) from the PC 111 via the communication processing unit 123, as shown in S1301 in FIG. Thereby, the input information for the route change process in S852 of FIG. 2 is received.

  Step S1302: Next, the path change control unit 842 checks whether the transmission source IP address of the ARP request 1061 received from the PC 111 is the IP address of the control target device. Here, since the first IP telephone 114 is a high priority communication apparatus and the communication apparatus that performs communication via the first router 112 other than the first IP telephone 114 is a low priority communication apparatus, the source IP address Check whether it is other than IP_router. Since the transmission source IP address 913 of the PC 111 which is the transmission source of the ARP request 1061 is IP_PC as shown in FIG. 8, this condition is satisfied.

  Steps S1303 to S1305: Next, the path change control unit 842 checks whether the destination IP address 915 of the ARP request 1061 from the PC 111 is an IP_router (S1303). Since the destination IP address 915 of the ARP request 1061 is an IP_router, it waits for a certain time (S1304). Thereafter, the route change control unit 842 generates route change control data, which is the unicast ARP request 1062 shown in FIG. 5, and transmits the route change control data to the PC 111 that is the control target device via the communication processing unit 123 (S1305). The destination IP address 915 and the source address 913 specified here are obtained by replacing the destination IP address 915 and the source IP address 913 of the received ARP request 1061. Further, the MAC_None that is the MAC address of the fictitious device 115 shown in FIG. 4 is set as the source MAC address 912. Here, the MAC address of the fictitious device 115 is an arbitrary MAC address different from the MAC address of the device existing in the LAN.

  Steps S1203 and S1204: Processing other than the route change control data generation processing (S1202) will be described again using FIG. While waiting for a certain period of time in the first IP telephone 114 in the route change control data generation process (S1202), the first router 112 transmits a normal ARP response 1063 to the received ARP request 1061 (S1203). Upon receiving this, the ARP table of the PC 111 is updated as shown in the table 1172 of FIG. 7B (S1207).

Although not shown in the figure, when the route change control unit 842 receives a broadcast ARP request from a device other than the control coping device, for example, the first router 112, the route change control data generation processing (S1202) In step S1302, it is checked that the source IP address is not a control target device (S1302). However, the priority information holding unit 841 needs to notify the route change control unit 842 of the IP address of the device to be controlled in advance. In this case, since the route change control unit 842 of the first IP telephone 114 does not generate any route change control data and does not return any response, the route of data transmitted from the first router 112 is not changed. Absent.

(3) Procedure 3
Step S1205: PC 111 which is a control target apparatus which has received the route change control data 1062, and updates the ARP table based on the route change control data 1062 (S1205). The state of the ARP table at this time is as shown in the table 1173 of FIG. 7C, and MAC_None that is a MAC address not existing in the LAN is registered as the MAC address corresponding to the IP_router.

  Note that the reason for performing the process of waiting for a certain time (S1304 in FIG. 6) is that if this process is not performed, the data arrives in the order of the path change control data 1062 and the ARP response 1063 from the router in the PC 111. This is because the ARP table 1021 finally becomes the table 1172 in FIG. 7B, and as a result, there is a possibility that the route cannot be changed.

(4) Procedure 4
Step S1206: As a result, the ARP table 1021 of the PC 111 becomes like the table 1173 of FIG. Thereafter, when the PC 111 attempts to transmit low priority communication data, it transmits communication data 1064 (see FIG. 4) destined for MAC_None (the MAC address of the fictitious device 115). Here, since the imaginary device 115 does not actually exist, the communication data 1064 is discarded without being received by any device. Therefore, after the route change, the communication 131 between the PC and the server, which is low priority communication, is interrupted.

  The return control data can also be transmitted as the route change control data 1062 that restores the ARP table of the PC 111 that is the control target device. At this time, in the return control data, the transmission source MAC address is changed to MAC_router. In this case, the MAC_router is also required as information regarding low priority communication that the priority information holding unit 841 notifies the route change control unit 842 in S851 of the procedure 1. Further, when the PC 111 as the control target device transmits an ARP request by broadcast again, the interrupted low priority communication can be resumed by a method of not transmitting the route change control data.

  Furthermore, it is possible to adjust the communication amount of low priority communication by adjusting the interval between interruption and resumption. For example, if low-priority communication in the PC 111 is performed by TCP, the transmission rate of low-priority communication gradually increases due to TCP flow control when restarting after interruption, and congestion occurs again after a certain time. Therefore, it is possible to control the transmission rate such that the time until congestion occurs again is measured dynamically and the next time is interrupted again at the timing immediately before the occurrence of congestion. When the interruption and restart processes are repeated a plurality of times, the procedure 3 may be omitted for the second and subsequent times.

  Further, when the high priority communication is completed, the ARP table of the PC 111 that is the control target device is restored to the original by the above method, so that after the high priority communication is completed, the communication path before the route change is restored. It is also possible to continue the communication 131 between the PC and the server, which is communication.

  If the transfer speed of the access line 106, which is a line in which congestion occurs, is known, it is determined at what interval the interruption and resumption should be performed in order to secure the QoS of high priority communication. You can also At this time, the relational expression between the transfer speed of the access line 106 and the interval of interruption / resumption can be obtained by conducting an experiment, for example.

  It is also possible to use a broadcast ARP request as the route change control data 1062. However, in this case, there is a possibility that another host that has received the ARP request determines that there are a plurality of communication devices having the same IP address, and communication cannot be continued normally. Further, the ARP response 1063 can be used as the route change control data 1062. However, in some implementations, when the control target apparatus receives the ARP response 1063 after transmitting the ARP request 1062, it does not receive another ARP response for a certain period of time, that is, the former becomes effective when a plurality of ARP responses arrive. Further, there is an implementation in which the ARP response 1063 is always accepted, that is, the latter becomes effective when a plurality of ARP responses arrive. Therefore, the route change control unit 842 of the present invention transmits a plurality of ARP requests, that is, route change control data 1062 so that it arrives both before and after the arrival of the ARP response 1063 to which the first router 112 responds. May be necessary.

  Further, here, a case has been described in which the control target device is the PC 111 that is a device that terminates low priority communication, that is, a case where the uplink communication path of the access line 106 is changed. However, even when the control target device is the first router 112 which is a device that relays low priority communication, that is, when the downstream route of the access line 106 is changed, it can be carried out by substantially the same procedure. That is, when determining whether or not the transmission source IP address is the control target device in S1302 of FIG. 6, control is performed when the transmission source IP address is the IP address of the first router 112. Then, instead of determining whether or not the destination IP address is the first router 112 in S1303 of FIG. 6, control may be performed when the destination IP address is not the first router 112. That is, the destination IP address is the IP address of another communication terminal that is not the first router 112. In this way, by changing the downstream path, for example, when flow control is performed like TCP, the data packet does not arrive at the PC 111, the PC 111 does not transmit an ACK packet to the server, and the server Since the ACK packet cannot be received from the server, the server cannot transmit a new packet. Therefore, the data transmission rate from the server to the PC 111 can be lowered. Further, when both the device that terminates the low priority communication and the relay device are set as control target devices, the route change control data may be transmitted without performing S1302 and S1303.

  With the above configuration, the following operational effects can be obtained in the first embodiment. When a communication device that performs priority control generates and transmits path change control data and communication between high priority communication and low priority communication is congested, the communication path of low priority communication is changed. Accordingly, a communication path for high priority communication can be secured with priority. As described above, the communication device that performs priority control can control communication according to the priority in addition to the communication function. Therefore, by connecting a communication device that performs the above-described priority control to a home LAN that does not perform communication control according to priority, communication is performed via the network using the communication device that performs priority control. However, QoS for high priority communication can be ensured. Therefore, in order to ensure QoS, it is not necessary to provide a separate dedicated router that controls communication according to priority. Therefore, the user does not need to change the existing router or system configuration, and can subscribe to an arbitrary provider and perform real-time communication such as an IP phone with high quality. Further, the QoS of the high-priority communication device can be changed without changing the entire system including the low-priority communication device, the high-priority communication device, and the relay device by simply providing a communication device that performs priority control capable of ensuring QoS. Can be secured.

  As a high-priority communication apparatus that performs high-priority communication, for example, an IP telephone or the like that requires real-time performance such as telephone communication can be cited. Moreover, as a low priority communication apparatus, the terminal etc. which perform a file transfer etc. are mentioned, for example. Therefore, real-time performance can be maintained by securing the QoS of the IP telephone using a communication device that performs priority control.

  In addition, when transmitting 1st control data to a low priority communication apparatus, the communication path from a low priority communication apparatus to the other party's communication apparatus can be changed. Further, when the first control data is transmitted to the relay device, the communication path from the counterpart communication device to the low priority communication device can be changed.

  Hereinafter, supplementary items regarding the present embodiment will be described in each section (<Applied environment>, <Installation position>, <Route change method>, and <Route change timing>).

<Applicable environment>
Up to this point, the example of the environment to which the first IP telephone 114 having the QoS control unit 621 of the present invention can be applied has been described using the network configuration of FIG. 1, but the present invention can be applied to a more general network configuration. It is.

  Before describing what kind of network configuration is applicable, here is a brief summary of the procedure by which the QoS problem that occurs in the configuration of FIG. 1 occurs.

  Generation procedure IP phone-IP phone communication 132 between the first IP telephone 114 in the first home 101 and the second IP telephone 117 in the second home 104, and between the PC and server between the PC 111 and the server 113. Communication 131 is performed simultaneously.

  Generation procedure The access line 106 is slower than the LAN line 107, and the first router 112 serving as a relay point competes for communication and congestion occurs.

  Generation procedure 3. Since priority control is not performed in the first router 112, the QoS of IP telephone communication decreases.

  In general, the above situation can be paraphrased as follows.

  Generation procedure High priority communication and low priority communication are performed simultaneously.

  Generation procedure Congestion occurs in a device that relays from a high-speed line to a low-speed line.

  Generation procedure 3. Since priority control is not performed in the relay device, the QoS of high priority communication decreases.

  The present invention is generally applicable in such a situation. That is, in the above, an IP telephone is taken as an example of a communication apparatus having the QoS control unit 621 of the present invention, but the communication apparatus is not limited to a PC, a server, or an IP telephone, and may be a DVD recorder, an IP video telephone, or the like. . The low-speed line need not be limited to the ADSL uplink line, and may be a wireless LAN line or a light line. Further, the present invention is not limited to an environment connected to the Internet, and can be applied to a case where a plurality of communications are simultaneously performed in a network environment closed to a home LAN, a corporate LAN, a regional IP network, or the like.

<Installation position>
Further, the present invention has been described as being implemented as the QoS control unit 621 in the first IP telephone 114 in FIG. 1, but it may be installed at other positions as shown in FIG. 9, the first IP telephone 114 having the QoS control unit 621 of the present invention and the QoS control units 1581 to 1585 having the functions thereof are arranged at various positions in FIG. Since the network configuration is the same as that in FIG.

  As shown in FIG. 9, the QoS control unit 621 can be installed independently of the IP telephone as long as it is connected to the home LAN. That is, the QoS control device 1583 having the above-described QoS control unit 621 may be provided as one terminal connected to the LAN side of the first router 112. The QoS control device 1583 is a single device having only the QoS control unit 621 as a functional unit as shown in FIG. Further, the QoS control devices 1585 and 1582 may be connected between the devices 111 and 114 connected to the first router 112 and the first router 112. However, when connecting between the first router 112 and the other devices 111 and 114, the QoS control devices 1585 and 1582 are bridges that relay communication between the first router 112 and the other devices 111 and 114, It operates as a repeater in the data link layer, which is the second layer.

  1 shows an example in which QoS control processing is implemented as the QoS control unit 621 in the first IP telephone 114, but a similar QoS control unit is installed in the PC 111 or the first router 112 as shown in FIG. 1584 and 1581 may exist.

  In some cases, the first IP telephone 114 having the QoS control unit 621 of the present invention is installed in a place other than the home LAN, and the effect is exhibited. Will be described in the description of the case where the route change control data is a DNS reply packet).

<Route change method>
So far, the procedure in the case of using the ARP request / ARP response as the procedure 1 to procedure 4 of <the overall flow of QoS control processing> has been described. However, as another method, an ICMPv6 neighbor discovery packet is used. There are a method, a method using an ICMP route change (redirect) packet or an ICMPv6 route change (redirect) packet, a method using a DNS reply packet, a method using a DHCP or DHCPv6 packet, a method of installing software on a PC, and the like. The procedure when these are used will be described below. However, the route changing method used in the present invention is not limited to these, and any method may be used.

[When using ICMPv6 neighbor search packet]
Here, a procedure when an ICMPv6 neighbor search packet is used as route change control data for route change will be described.

  First, the function of the ICMPv6 neighbor search packet will be briefly described. Neighbor Discovery in IPv6 (Internet Protocol Version 6) is defined in RFC 2461, and basically provides the same functions as ARP in IPv4 (Internet Protocol Version 4). That is, in Ethernet (registered trademark), a protocol for notifying the correspondence between an IPv6 address and a MAC address (an address unique to network I / F hardware) between devices communicating within a LAN. The ICMPv6 neighbor discovery packet includes a neighbor solicitation message corresponding to an ARP request in IPv4, a neighbor notification message corresponding to an ARP response in IPv4, and the like.

  The control sequence and packet flow when using the neighbor notification packet as the route change control data are the same as those in the case where the route change control data shown in FIG. 4 and FIG. Details are omitted.

  Changes 1. ARP requests 1061 and 1062 are changed to neighbor solicitation packets.

  Changes 2 The ARP response 1063 is changed to a neighbor notification packet.

  Changes 3 The ARP table is changed to the ND cache table.

  Regarding the changes 1 and 2, since the packet format also needs to be changed, the neighbor request, the message format of the neighbor notification packet, the source MAC address (912 in FIG. 3) of the ARP request / response, the source IP A brief description will be given of which fields in the neighbor solicitation / neighbor notification packet the address 913, the destination MAC address 914, and the destination IP address 915 correspond to. FIG. 11 simply shows the format of the neighbor solicitation packet and the neighbor notification packet. First, the control source MAC address 9201, target IP address 924, target MAC address 925, and destination IP address 9212 of the neighbor solicitation packet in FIG. 11 are the source MAC address 912 and the source IP address 913 in the ARP request in FIG. , Corresponding to the destination MAC address 914 and the destination IP address 915. Further, the start point MAC address 945, the source IP address 9411, the destination MAC address 9402, and the target IP address 944 of the neighbor notification packet in FIG. 11 are respectively the source MAC address 912, the source IP address 913 in the ARP response in FIG. It corresponds to the destination MAC address 914 and the destination IP address 915. When using the neighbor notification packet as the route change control data, it is desirable to enable the overwrite flag 943 present in the ICMPv6 header 942 in order to rewrite the ND cache of the device to be controlled more reliably.

  Note that the neighbor request packet can be used in the same manner as the ARP response packet can be used as the route change control data. As shown in FIG. 11, the format of the neighbor solicitation packet is the same as that of the neighbor notification packet and corresponds to the ARP request. Further, as a kind of ICMPv6 neighbor search packet, there is a router advertisement packet, which can be used as route change control data. The router advertisement packet is a message for the router to inform the host that is the device to be controlled that it is the default gateway. The host that is the control target device that has received this registers the IP address that is the transmission source of the router notification packet in the routing table as the IP address of the default gateway. The valid time is a value set in the “router valid time” field of the router notification packet. In this way, when the router notification packet is used as the route change control data, a packet in which the value of the “router valid time” field is set to 0 is used. At this time, the host that has received the router notification packet interprets that the source IP address of the router notification packet is no longer the default gateway, and deletes the entry from the routing table. As a result, the control target device can no longer transmit packets.

  In this state, when a router notification packet in which an arbitrary IP address is set as a transmission source IP address with a value other than 0 in the “router valid time” field is transmitted to the control target device as route change control data, the control target device is hereinafter referred to. Can recognize that the set IP address is the default gateway.

[When using ICMP route change packet]
Here, a procedure (procedure 1 to procedure 4) when an ICMP route change packet is used as route change control data for route change will be described.

  First, the function of the ICMP route change packet will be briefly described. Usually, route control in IP is performed by referring to the routing table of each device. In the routing table, an address of a router (this is referred to as a gateway) through which IP packets are first transmitted when an IP packet is transmitted to a network outside the LAN is set. When the ICMP route change packet is used as route change control data, the gateway address in the routing table of the device to be controlled can be rewritten, thereby changing the route of low priority communication. FIG. 12 shows a packet format of the ICMP route change packet. Hereinafter, the route change procedure when the ICMP route change packet is used in the network of FIG. 1 will be described with reference to FIGS. 13 to 15 in addition to FIGS. FIG. 13 is a schematic diagram showing a data flow in the QoS control procedure when an ICMP route change packet is used, and shows how each piece of data 1661 and 1662 exchanged moves on the network. FIG. 14 is an example of processing and data flow in the QoS control procedure when an ICMP route change packet is used, and shows a time series of each data exchange and QoS control processing in the first IP telephone 114 in this procedure. . FIGS. 15A and 15B are routing tables of the control target device, and show how the routing table 1621 of the PC 111 is updated as needed in the following procedure. In the following procedure, the MAC address and IP address of the PC 111, the first router 112, the server 113, the first IP telephone 114, and the fictitious device 115 are as defined in FIG.

(1) Procedure 1
The procedure 1 will be described with reference to FIG. First, in the present embodiment, the IP telephone communication performed by the first IP telephone 114 which is its own apparatus is a high priority communication, and all the communication from the LAN to the Internet via the first router 112 is a low priority communication. It is assumed that the QoS control unit 621 of the present invention operates. At this time, the priority information holding unit 841 in FIG. 2 has, as default information, an IP_router value necessary for route change control by the ICMP route change packet and an IP_PC value as the IP address of the control target device. Here, the IP_router is an IP address of the first router 112 that relays communication from the PC 111 and the first IP telephone 114 to the network 2 as shown in FIG. Note that this information is not predetermined information, and may be input from a user interface, or may be acquired by some procedure using a network.

  Next, the priority information holding unit 841 notifies the route change control unit 842 of this IP_router and IP_PC as information related to low priority communication (S851 in FIG. 2). Note that the IP address of the control target device is not included here, and the following procedure 2. May be acquired from a broadcast ARP request transmitted by the device to be controlled.

(2) Procedure 2
The procedure 2 and subsequent steps will be described with reference to FIGS. However, FIG. 12 is referred to regarding the format of the ICMP route change packet.

  Step S1701: The route change control unit 842 of the first IP telephone 114 transmits an ICMP route change packet as route change control data 1661. At this time, the source address of the IP header 931 of the ICMP route change packet is IP_router, and the destination address is IP_PC. Also, IP_None, which is the IP address of the fictitious device, is specified as the router IP address 933. Here, the IP address of the fictitious device is an arbitrary address different from the IP address of the device existing in the home LAN.

(3) Procedure 3
The routing table of the PC 111 before receiving the route change control data 1661 is as a table 1871 in FIG. 15A. IP_router is set as the IP address of the gateway that transfers the packet addressed to the server 113 in FIG.

  Step S1702: Here, when the PC 111 receives the route change control data 1661, it updates its own routing table. At this time, the routing table is as shown in the table 1872 of FIG. 15B, and the fictitious IP address IP_None is associated as the transfer destination of the packet addressed to the server 113.

(4) Procedure 4
Step S1703: Through the above processing, when the PC 111 transmits communication data to the server 113, it tries to transmit low priority communication data using the IP address of the fictitious device as a gateway.

  Step S1704: At this time, in order to actually transmit data, since the PC 111 needs to know the MAC address for the fictitious IP address IP_None, it transmits a broadcast ARP request 1662. However, since there is no device having the designated destination IP address 915, the ARP request 1662 is discarded. As a result, the PC 111 cannot transmit the low priority communication data, and the communication between the PC and the server after the path change is interrupted.

  The interrupted low priority communication can be resumed by transmitting the return control data as the route change control data that restores the routing table of the PC 111 that is the control target device. Furthermore, it is possible to adjust the communication amount of low priority communication by adjusting the interval between interruption and resumption. When the interruption and restart processes are repeated a plurality of times, the procedure 1 may be omitted for the second and subsequent times. If the transfer speed of the access line 106 shown in FIG. 1, which is a line where congestion occurs, is known, what interval should be interrupted and resumed to secure QoS for high priority communication from that value? You can also decide if it ’s good. At this time, the relational expression between the transfer speed of the access line 106 and the interval of interruption / resumption can be obtained by conducting an experiment, for example.

  Furthermore, when high-priority communication ends, the routing table of the control target device is restored to the original by the above-described method, so that after high-priority communication ends, the communication path before the path change is restored, and low-priority communication is performed. The communication 131 between the PC and the server can be continued.

  The ICMP route change packet described above can be used only in an IPv4 network, but an ICMPv6 route change packet that exhibits the same effect can be used in an IPv6 network. The processing when the ICMPv6 route change packet is used as the route change control data is the same as that when the ICMP route change packet is used, and the details are omitted here.

[When using DNS reply packet]
Here, a procedure (procedure 1 to procedure 4) when using a DNS reply packet as route change control data for route change will be described.

  First, DNS (Domain Name System) will be briefly described. DNS is a function for obtaining a corresponding IP address from a host name indicated in a name format called FQDN (Fully Qualified Domain Name) (eg, www.panasonic.co.jp).

  In order to use the DNS, the communication application transmits a DNS inquiry packet including the FQDN to the DNS server. On the other hand, a DNS reply packet (including an IP address corresponding to the inquired FQDN) transmitted from the DNS server is received, and thereafter, communication is performed with respect to the IP address.

  Hereinafter, a route change procedure when a DNS reply packet is used will be briefly described with reference to FIGS. 1, 2, and 8. The relationship between FIGS. 1 and 2 and FIG. 8 are as already described.

(1) Procedure 1.
The procedure 1 will be described with reference to FIG. First, in the present embodiment, the IP telephone communication performed by the first IP telephone 114 which is its own apparatus is a high priority communication, and all the communication from the LAN to the Internet 2 via the first router 112 is a low priority communication. Assuming communication, the QoS control unit 621 of the present invention operates. At this time, the priority information holding unit 841 in FIG. 2 has the IP_router value and the MAC_router value necessary for route change control by the DNS reply packet as default information. Note that this information is not predetermined information, and may be input from a user interface, or may be acquired by some procedure using a network.

  Next, the priority information holding unit 841 notifies the route change control unit 842 of the IP_router and the MAC_router as information on low priority communication (see S851 in FIG. 2).

(2) Procedure 2
Here, the method once used in the case of the ARP request / ARP response / ICMP path change packet is applied to change the destination of the DNS inquiry packet and direct it to the first IP telephone 114 having the QoS control unit 621 of the present invention. The IP_router acquired as information related to low priority communication is used here.

  The first IP telephone 114 receives the DSN inquiry packet and stores various information necessary for creating a DNS answer packet such as FQDN included therein. The route changed by the ARP request / ARP response / ICMP route change packet may be returned at an arbitrary timing thereafter.

The route change control unit 842 of the first IP telephone 114 transmits a DNS reply packet as route change control data to the PC 111 that is a device to be controlled. In this case, setting the IP_None (see FIG. 8) is the IP address of the imaginary device corresponding to FQND contained in the DNS query packet. Note that the source IP address and destination IP address of the route change control data are obtained by replacing the source IP address and destination IP address of the DNS inquiry packet. In addition, an IP_router acquired as information on low priority communication is set in the source MAC address.

(3) Procedure 3.
The PC 111 that is the control target device that has received the route change control data transmits low priority communication data with a nonexistent IP address as a destination.

(4) Procedure 4.
However, it is detected that no destination host exists in any router on the communication path, and an ICMP destination unreachable message is transmitted to the PC 111. Receiving this, the PC 111 detects an error, and usually the communication application interrupts communication.

  In <Installation Position>, it is described that the PC 111 as the control target device and the first IP telephone 114 having the QoS control unit 621 of the present invention need to be in the same LAN. However, when the DNS reply packet is used as the route change control data, it is not always necessary that the control target device and the first IP telephone 114 having the QoS control unit 621 of the present invention exist in the same LAN. For this reason, the device to be controlled may be any of the devices at both ends that perform low priority communication. In addition, the place where the first IP telephone 114 having the QoS control unit 621 of the present invention is present may be anywhere as long as IP communication with the control target apparatus is possible.

  The above DNS reply packet can be used in both IPv4 and IPv6.

[When using DHCP and DHCPv6]
Next, a case where DHCP and DHCPv6 are used will be described. DHCP (Dynamic Host Configuration Protocol) is a protocol for acquiring information such as an IP address of a host that is a client, a default gateway to be used, a DNS server, and the like from a server, and can be used in an IPv4 network. In DHCP, after a client exchanges a message for detecting a server, a DHCPREQUEST (DHCP request) packet is transmitted to the detected server, and a DHCPACK (DHCP response) transmitted from the server in response to this packet is transmitted. The client is set by receiving the packet (including the information described above).

  DHCPv6 is a protocol that can be used in IPv6 and provides almost the same functions as DHCP. However, DHCPv6 is different from DHCP in that a default gateway cannot be set. In DHCP, processing is always performed in such a manner that the server responds to a request from the client, whereas in DHCPv6, a RECONFIGURE (re-setting) packet for overwriting setting from the server side can be used.

  By using the DHCPACK packet or RECONFIGURE packet in these protocols as the route change control data, the default gateway of the control target device is changed, and the same effect as the case of using the ICMP route change packet described above can be obtained, or the control target By changing the DNS server to be referred to, it is possible to obtain the same effect as the prior route changing method based on the ARP request or the like when the DNS reply packet is used.

  Note that DHCP is specified in RFC2131 and DHCPv6 is specified in RFC3315.

[When using software on a PC]
Here, a procedure (procedure 1 to procedure 4) in the case where the path change control is performed using software installed in the PC will be described.

  When the control target device is a general-purpose computer such as a PC, the data path transmitted by the control target device can be changed by installing software therein. It is assumed that the software has been installed on the PC before this procedure starts. Hereinafter, the procedure will be described with reference to FIGS. 1, 2, and 12. The relationship between FIGS. 1 and 2 and FIG. 12 are as already described.

(1) Procedure 1
In this method, the procedure 1 for notifying the low-priority communication of information from the priority information holding unit 841 to the route change control unit 842 is unnecessary.

(2) Procedure 2.
The route change control unit 842 of the QoS control unit broadcasts a special packet that can be recognized by software installed in the PC 111 as route change control data. If the address (IP_PC or MAC_PC) of the PC 111 that is the control target device is known in advance, unicast may be used. In the route change control data, an address that does not exist is set as information on the address to be transferred. If the transfer destination address is known in advance, it may be registered in advance in the PC software.

(3) Procedure 3
The PC 111 that is the control target device that has received the route change control data rewrites its own ARP table or routing table, or rewrites the destination MAC address or IP address of the communication data by some method by processing of software installed in advance. .

(4) Procedure 4
Thereafter, the PC 111 transmits low priority communication data with a non-existing MAC address or IP address as the destination, and as a result, the low priority communication between the PC and the server is interrupted.

  The interrupted low-priority communication can be resumed by transmitting route change control data that restores the data transfer destination of the control target device. Furthermore, it is possible to adjust the communication amount of low priority communication by adjusting the interval between interruption and resumption.

  Furthermore, when high-priority communication ends, the ARP table of the control target device is restored to the original by the above-described method, so that after high-priority communication ends, the communication path before the path change is restored and low-priority communication is performed. The communication 131 between the PC and the server can be continued.

<Route change timing>
Up to this point, the route is changed at the start of high priority communication as the timing for changing the route, and the timing for returning the route is at the end of the high priority communication. However, the present invention is not limited to this. Hereinafter, the timing of route change will be described.

  The timing at which the route change control data can be transmitted to the control target device varies depending on the route change control data. For example, when the route change control data is an ARP request, the route change control data can be transmitted at an arbitrary timing as long as the control target device once transmits the ARP request. However, in the case where the route change control data is a DNS reply packet, after the control target device transmits a DNS inquiry packet, the DNS reply packet reception waiting process cannot be received due to a timeout until the DNS reply packet cannot be received. The route change control data from the first IP telephone 114 having the QoS control unit 621 must be received.

  Although the timing at which the route change control data can be transmitted varies depending on the route change control data, the timing for changing the communication route based on the received route change control data and the effect thereof will be described below. However, this does not limit the timing of applying the present invention to the following, and may be performed at an arbitrary timing.

  First, the timing for changing the communication path of low priority communication from the normal communication path to another communication path can be considered as follows.

  Timing 1. The timing for changing the communication path of the low priority communication is determined when the first IP telephone 114 having the QoS control unit 621 of the present invention is powered on or the first IP telephone 114 having the QoS control unit 621 of the present invention is connected to the home LAN. Or the first time after that, that is, the timing at which processing can be started upon receipt of an ARP request packet. In this case, it is possible to change the route permanently, and the implementation is easy.

  Timing 2. The timing for changing the communication path of the low priority communication is the timing at which the high priority communication is started. In this case, since the communication path can be changed only during a period in which there is a possibility that communication may compete, it is possible to reduce the influence of low priority communication due to the change of the communication path.

  Timing 3. The timing for changing the communication path of the low priority communication is the timing when the quality of the high priority communication is deteriorated. In this case, the control is complicated, but the period in which the communication path is changed is set to the timing 2 described above. It can be made even shorter. It should be noted that the criterion for quality degradation is determined from statistical information of information (delay, jitter, packet loss rate, etc.) relating to the quality of high priority communication. As a method for the first IP telephone 114 having the QoS control unit 621 of the present invention to acquire information relating to the quality of high priority communication, quality information is collected in a device that terminates high priority communication, and a packet including the information is collected. Is easily transmitted to the first IP telephone 114. Furthermore, when a QoS control unit exists in a device that terminates high-priority communication, quality information can be passed within the device.

  Next, the timing for returning the communication path once changed can be considered as follows.

  Timing 1. The timing for returning the communication path to the original time is when the first IP telephone 114 having the QoS control unit 621 of the present invention is shut down or restarted. In this case, it is possible to eliminate the influence on the low priority communication during the period in which the first IP telephone 114 cannot be controlled.

  Timing 2. The timing for returning the communication path to the original timing is the timing when the high priority communication ends. In this case, since the path can be changed only during a period in which communication may compete, it is possible to reduce the influence of low-priority communication due to the path being changed.

  Timing 3. The timing for returning the communication path to the original timing is a timing when it is determined that the quality of the high-priority communication is ensured even if the communication path is returned due to a decrease in the communication amount of the low-priority communication. In this case, the control is complicated, but the period during which the communication path is changed is set to 2. It can be made even shorter. Note that the criterion for determining whether high-priority communication quality is ensured even when the route is returned is determined based on statistical information on information (delay, jitter, packet loss rate, etc.) regarding the quality of high-priority communication. . As a method for the first IP telephone 114 to acquire information on the quality of high-priority communication, quality information is collected in a device that terminates the high-priority communication, and a packet including the information is transmitted to the first IP telephone 114. How to make it easy. Furthermore, when a QoS control unit exists in a device that terminates high-priority communication, quality information can be passed within the device.

  The priority information holding unit in the claims corresponds to the priority information holding unit 841, and the route change control unit in the claims corresponds to the route change control unit 842.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 16 is a network configuration diagram according to the second embodiment. In FIG. 16, the PC 111 and the first IP telephone 114 are connected to the LAN side of the first router 112 existing in the first home 101 to form a home LAN. The home LAN is connected to the Internet 102 via the access line 106 and the first ISP 103. The second router 116 is also present in another second home 104, and a second IP telephone 117 is connected to the LAN side. The home LAN of the second home 104 is connected to the Internet 102 via the second ISP 105.

  In FIG. 16, file transfer 131 (hereinafter referred to as PC-server communication 131) is transmitted between the PC 111 in the first home 101 and the server 113 on the Internet 102, and the first IP telephone 114 in the first home 101. IP telephone communication 132 (hereinafter referred to as IP telephone-IP telephone communication 132) using the Internet 102 is performed with the second IP telephone 117 in the second home 104.

  In FIG. 16, the QoS control unit 121 is mounted as one function unit of the IP telephone 114. FIG. 17 shows in more detail the internal configuration of the IP telephone 114 and the QoS control unit 121 in FIG. As illustrated in FIG. 17, the QoS control unit 121 includes a priority information holding unit 841, a path change control unit 842, and a communication control unit 120. The communication control unit 120 controls output of transmission data from the low priority communication apparatus to the network, and includes an analysis unit 127, a selection unit 128, and an adjustment unit 126. The route change control unit 842 can receive data from the LAN line 107 and transmit data to the LAN line 107 via the communication processing unit 123 in the IP telephone 114. Here, it is assumed that the communication processing unit 123 conforms to the Ethernet (registered trademark) protocol. That is, the communication processing unit 123 includes a PHY unit 172 and an EtherMAC unit 171. The voice data of the IP phone is generated by the voice data generation unit 122 and transmitted to the LAN line 107 via the communication processing unit 123. Here, the communication 132 between the IP phone and the IP phone is a communication that requires real-time property, and is a high priority communication with a high priority. On the other hand, the communication 131 between the PC and the server is a low priority communication with a low priority. The first IP telephone 114 is a high priority communication device, and the PC 111 is a low priority communication device.

  The difference of this embodiment from the first embodiment is as follows. In the first embodiment, when a route is changed, low priority communication is interrupted by recognizing an address that does not exist for the control change target device as a destination, whereas in the second embodiment, control is performed. By causing the change target device to recognize the address of the first IP telephone 114 having the QoS control unit 121 as a destination, the QoS control unit 121 once receives low-priority communication data. That is, in the first embodiment, the QoS control unit only changes the communication path, whereas in the second embodiment, the QoS control unit 121 further includes an analysis unit 127, a selection unit 128, and an adjustment unit 126. And performs more detailed control on the received low priority communication data.

  Hereinafter, in the second embodiment, as shown in FIG. 16, the first IP telephone 114 having the QoS control unit 121 of the present invention sets the communication path of the low-priority PC-server communication 131 to the first IP telephone. The procedure for securing QoS for high-priority communication by performing detailed QoS control in the first IP telephone 114 will be described. The outline of the QoS control process of the present invention will be described first in <Overall flow of QoS control process>, and then the details of each procedure will be described in <Detailed procedure of QoS control process>.

<Overall flow of QoS control>
The QoS control process in the second embodiment is roughly performed according to the following procedure.

First, as a state before the QoS control process is performed, it is assumed that only low priority communication (PC-server communication 131) is performed in the network of FIG. Thereafter, when high-priority communication (IP phone-IP phone communication 132) is started, the QoS control unit 121 performs the following control. Hereinafter, a description will be given with reference to FIG.

(1) Procedure 1
The priority information holding unit 841 holds priority information for distinguishing between low priority communication and high priority communication, and notifies this to the route change control unit 842 (S851). Here, the first IP telephone 114 is set as a high priority communication apparatus that performs high priority communication, and the PC 111 is set as a low priority communication apparatus that performs low priority communication.

(2) Procedure 2
The route change control unit 842 obtains information such as an IP address necessary for generating route change control data for route change (S852). The information collected here differs depending on the route change method.

  The route change control unit 842 generates route change control data from the information acquired here and the information obtained by the procedure 1, and sends the route change control data to the PC 111 that terminates or relays the low-priority communication that is the control target device for the route change. Then, route change control data for route change is transmitted (S853).

  The communication processing unit 123 sends this route change control data to the LAN line 107. The route change control data includes information on the destination after the change of the data output from the PC 111 which is a low priority communication device. In the present embodiment, the address of the first IP telephone 114 itself having the QoS control unit 121 of the present invention is used as the destination after the change.

(3) Procedure 3
The PC 111 that is a low-priority communication device and is a device to be controlled is a communication device that has received the route change control data and has changed the data of the subsequent low-priority communication, that is, the QoS control unit 121. It transmits to the route via the first IP telephone 114.

(4) Procedure 4
The QoS control unit 121 receives the low priority communication data via the communication processing unit 123 (S1951), and the analysis unit 127, the adjustment unit 126, the selection unit 128, etc. The process is performed, and then transferred to the correct destination (S1952). The communication path of the low priority communication at this time is the PC-server communication 133 after the path change in FIG.

<Detailed procedure for QoS control>
Next, the detailed procedure when the above procedure is performed will be described with reference to FIGS. 17 to 20 in addition to FIG. 16 with respect to steps 1 to 4 of <Overall flow of QoS control processing>. This will be described below. FIG. 17 is a block diagram of the QoS control unit and the IP telephone in the second embodiment, and shows the time series of each data exchange and processing in the first IP telephone 114 in this procedure. FIG. 18 is an example of processing and data flow when performing detailed control after route change control. 19 and 20 show how the ARP table and routing table of the PC 111 are updated as needed.

  Hereinafter, it demonstrates along the flow of a process.

(1) Procedure 1
The procedure 1 will be described with reference to FIG. First, in the present embodiment, the IP telephone communication performed by the first IP telephone 114 which is its own apparatus is a high priority communication, and all the communication from the LAN to the Internet 2 via the first router 112 is a low priority communication. Assuming communication, the QoS control unit 621 of the present invention operates. At this time, the priority information holding unit 841 in FIG. 17 has the IP_router value necessary for route change control by the ARP request as default information.

Next, the priority information holding unit 841 notifies the IP_router to the route change control unit 842 as information on low priority communication (see S851 in FIG. 17).
(2) Procedure 2
Step S1401: Next, the PC 111, which is a device in the LAN that terminates the low-priority communication, is the IP address of the first router 112 that first passes to communicate with the server 113, as in S1201 of FIG. A broadcast ARP request 1061 is transmitted with the IP_router as the destination IP address 915.

Note that the routing table of the PC 111 after receiving the ICMP route change packet is as shown in a table 1873 of FIG. In addition, the above difference does not depend on whether the route change control data uses an ARP request / ARP response / ICMP route change packet / DNS reply packet / special packet that can be recognized by software on the PC. In the embodiment, description on <route changing method> is omitted.

  Thereafter, the route change control unit 842 in the QoS control unit performs the route change control data generation process of S1402. Only the change destination address of the communication path set by the path change control data is different from that of the first embodiment, and the details of the other processes are the same as those in the flowchart of FIG. To do. The destination IP address 915 and the source address 913 specified here are obtained by replacing the destination IP address 915 and the source IP address 913 of the received ARP request 1061. Further, MAC_QoS which is the MAC address of the first IP telephone 114 having the QoS control unit 121 is set in the transmission source MAC address 912.

(3) Procedure 3
Step S1405: The PC 111 that is the control target device that has received the path change control data 1062 updates the ARP table based on the path change control data 1062. The state of the ARP table at this time is as shown in the table 1174 of FIG. 19, and MAC_QoS which is the MAC address of the first IP telephone 114 having the QoS control unit 121 is registered as the MAC address corresponding to the IP_router. Yes.

(4) Procedure 4
Step S1406: Next, the PC 111 performs communication data transmission processing. At this time, since the low-priority communication path has already been changed to the first IP telephone 114 having the QoS control unit in the procedure 3, the communication data 2061 is transmitted to the first IP telephone 114.

  The first IP telephone 114 receives the communication data 2061, performs detailed control (S2001), and transmits it. Hereinafter, an example of reception processing and transmission processing (including detailed control) will be described with reference to FIGS. 17, 21, 22, and 23.

[Reception processing]
The Ethernet (registered trademark) frame (FIG. 21A) detoured to the first IP telephone 114 is extracted by the Ethernet (registered trademark) MAC unit 171 via the PHY unit 172. The Ethernet (registered trademark) MAC unit 171 sends the destination address (DA), transmission source address (SA), type, and payload data of the extracted frame to the analysis unit 127 in the QoS control unit 121.

  The analysis unit 127 performs the operation shown in FIG. That is, when an Ethernet (registered trademark) frame (DA, SA, type, data) is received from the Ethernet (registered trademark) MAC unit 171 (S601 in FIG. 22), an IP protocol packet is stored in the frame from the type area. Find out if it is. If the value of the type is 0x0800, this is an IP protocol and a candidate for reception by the own device (first IP telephone 114) (S602). Next, as shown in S603, the destination IP address is checked from the IP header (FIG. 21C) in the Ethernet (registered trademark) frame (FIG. 21B), and it is determined whether or not it is a reception target. If it is a reception target, the frame is sent to the TCP / IP processing unit 124, which is the upper processing unit (S604). Those not in the IP protocol in S602 and those not addressed to themselves in S603 are written to the adjustment unit 126 (S605), and the DA and SA of the frame are rewritten by the adjustment unit 126 (S605). Specific contents to be rewritten will be described later. The adjustment unit 126 includes a storage unit that can store frames. In addition, the accumulation unit does not need to be included in the adjustment unit 126 and may be provided independently of the adjustment unit 126.

  The TCP / IP processing unit 124 performs TCP / IP protocol processing on the Ethernet (registered trademark) frame received from the analysis unit 127 and transmits it to an appropriate terminal application such as the IP phone application 122.

[Transmission process]
The transmission data from the IP telephone application 122 is subjected to transmission protocol processing by the TCP / IP processing unit 124, which is an upper processing unit, to form an Ethernet (registered trademark) frame, and is sent to the selection unit 128 in the QoS control unit 121. A send request is issued.

  The selection unit 128 performs the operation shown in FIG. That is, when there is a transmission request from the TCP / IP processing unit 124 (S701), the frame is read (S702) and transmitted to the Ethernet (registered trademark) MAC unit 171 (S705). On the other hand, if there is no request from the TCP / IP processing unit 124 (S701), then it is checked whether there is a transmission request from the adjusting unit 126 (S703) (note that a control data packet transmission request from the path change control unit) Etc., it is handled in the same manner as the transmission from the adjustment unit 126). If there is a transmission request from the adjustment unit 126, the frame is read from the adjustment unit 126 (S704) and transmitted to the Ethernet (registered trademark) MAC unit 171 (S705). When frame transmission is completed (S705), it is checked again whether there is a transmission request from the TCP / IP processing unit 124 (S701).

  The Ethernet (registered trademark) MAC unit 171 that has received the frame to be transmitted performs MAC processing such as adding an FCS (frame check sequence) and sends the frame to the transmission path via the PHY unit 172.

  In particular, by realizing each of the analysis unit, the adjustment unit, and the selection unit in hardware, a CPU that executes a terminal application or TCP / IP processing can avoid processing a frame that is not addressed to its own device. The transmission / reception frame of the PC 111 is not affected.

  Now, how the first IP telephone 114 operating as described above acts on the frame transmitted from the PC 111 to the server 113 to perform priority control will be described.

  First, as described above, an Ethernet (registered trademark) frame addressed to the server 113 from the PC 111 passes through the first IP telephone 114. In that case, the Ethernet (registered trademark) frame sent from the PC 111 originally sent the MAC address of the first router 112 as the destination address, but after the ARP table or the like was rewritten due to the route change, the first IP telephone 114 Is the destination address. However, since there is no change in the server 113 that is the communication partner, the destination IP address remains the IP address of the server 113.

  Since the destination MAC address of the Ethernet (registered trademark) frame transmitted from the PC 111 is the first IP telephone 114, it is detoured to the first IP telephone 114. In the first IP telephone 114, since the destination IP address of the frame is not the server itself but the server 113, the analysis unit 127 writes to the adjustment unit 126 as described above with reference to FIG. That is, the destination MAC address is set in the first IP telephone 114, but the IP address of the server 113 that is the original destination is set as the destination IP address of the upper protocol. For this reason, an Ethernet (registered trademark) frame sent from the PC 111 to the server 113 but bypassed to the first IP phone by rewriting the ARP table and sent to the server 113 and the Ethernet addressed to the first IP phone 114 itself. The (registered trademark) frame can be distinguished by the analysis unit 127. Further, the adjustment unit 126 sets DA, which is the destination MAC address of the stored frame, to the MAC address of the first router 112 (the packet relayed as shown in FIG. 18 is once transferred to the router (S2002), and then the server 113 (S2003), the source MAC address SA is rewritten to its own MAC address. The transmission frame of the PC 111 stored in the adjustment unit 126 is selectively multiplexed by the selection unit 128 as described above with reference to FIG. At this time, if there is a transmission frame from the IP telephone application of the first IP telephone 114, the transmission frame is selected and transmitted with priority. Therefore, the first IP telephone 114 transmits its own transmission frame (voice data) as the PC 111 transmission frame. Will be prioritized.

  24, 35, and 36, the relationship between the arrival (transmission request) and transmission (reading) at the selection unit of the transmission frame from the first IP telephone 114 (own transmission frame) and the relay frame received from the PC 111 is shown. . These are for explaining the detailed operations of transmission / reception and relay processing described so far (depending on whether the adjustment unit 126 has a buffer and whether the LAN line 107 is full duplex or half duplex). is there.

  First, FIG. 24 shows a case where the adjustment unit 126 has a buffer and the LAN line 107 is full duplex.

  In the case of (a) and (e): When there is no self-sending frame when the relay frame arrives and when there is no self-sending frame when transmission of the relay frame is completed, it is relayed as it is.

  In the case of (b): There is no self-sending frame when the relay frame arrives, but when a sending request for the self-sending frame is generated when the relay frame is being sent, the relay frame is sent at time t3. Upon completion, even if there is a request for transmission of the next relay frame from the adjustment unit 126, the self-sending frame is sent immediately and transmission is completed at time t4.

  Cases (c) and (d): This is a case where the relay frame arrives while the self-sending frame is being transmitted, and the relay frame starts to send the relay frame as soon as the self-sending frame has been sent (time t2). . Since the size of the buffer in the adjustment unit 126 is assumed to be large enough to store the frame, the relay frame can be kept waiting during the transmission of the self-sending frame.

  On the other hand, if the buffer size in the adjustment unit 126 is small, for example, equivalent to an elastic memory, as shown in FIG. 25, when a relay frame arrives while sending out its own transmission frame ((c) and (d) in FIG. 8). ), The relay frame is discarded.

  Further, the buffer in the adjustment unit 126 has a capacity capable of storing frames, and when the transmission path is half duplex, the transmission timing is as shown in FIG. That is, since it is a half-duplex transmission line, it cannot be transmitted during reception.

  In the case of (a): the self-sending frame cannot be sent until the relay frame is completely sent.

  In the case of (b): Although the relay frame has completed arrival, since there is a self-sending frame, the relay frame is sent first after sending the self-sending frame.

  In the case of (c): Since the self-sending frame is being sent, the relay frame cannot be received at this timing. The relay frame arrives at the timing (d).

  In the case of (d) and (e): When the relay frame arrives, there is no self-sending frame, so that it is sent as soon as the reception of the relay frame is completed.

  In the description so far, the selection unit 128 transmits the communication data 2062 for low priority communication only when there is no transmission request for high priority communication from the TCP / IP processing unit 124. Regardless of the presence or absence of communication data, the transmission data of the low-priority communication device may always be extracted from the buffer after a predetermined time and output to the network. Thus, by always outputting the low priority communication to the network after a certain time has elapsed, it is possible to perform control for ensuring the QoS of the high priority communication regardless of the presence or absence of the high priority communication.

<Detailed control after route change>
The detailed control performed by the first IP telephone 114 having the QoS control unit 121 of the present invention has been described as the priority control performed by the dedicated router in FIG. Any of the control methods may be used.

  However, priority control between such high-priority communication data and low-priority communication can be performed in FIG. 16, in which one function unit of the first IP telephone 114, which is the high-priority communication termination device, is the present invention. Because there was. When the first IP telephone 114 is not the same device as the high-priority communication termination device, for example, in the case of the position 1583 in FIG. 9 described above, the various route changing methods described so far are used. After changing the route of the high priority communication so as to pass through the first IP telephone 114, priority control between the high priority communication and the low priority communication may be performed in the selection unit 128. Note that the high-priority communication and low-priority communication paths at this time are the IP telephone-IP telephone communication 1531 after the path change and the PC-server communication 133 after the path change shown in FIG. become that way. In this case, the selection unit 128 uses, as priority information for distinguishing between low priority communication and high priority communication, an IP address or transport layer protocol (characterizing the low priority communication or high priority communication data). It is necessary to pass information such as TCP and UDP) and port number from the priority information holding unit 841 to the selection unit 128 (S1953). It should be noted that the information held by the priority information holding unit 841 may be a predetermined value, may be input from the user interface, or may be obtained by some means using a network. Also good.

  Further, even if the communication device of the present invention having the QoS control unit 121, which is exemplified by the first IP telephone 114, is different from the high-priority communication termination device, it can be performed without changing the high-priority communication route. There is also detailed control. In these cases, the adjustment unit 126 does not directly pass the low-priority communication received from the analysis unit 127 to the selection unit 128, but temporarily passes it to the adjustment unit 126, and returns the data returned from the adjustment unit 126 to the selection unit. Works to pass. In these cases, the selection unit 128 may transmit the received data in order without performing priority control.

  Some examples of detailed control in such a case will be described below, but some of them are processed by the adjustment unit 126.

  1. The adjustment unit 126 of the communication apparatus of the present invention discards part or all of the low priority communication packet.

  2. When the low-priority communication is TCP (Transmission Control Protocol), the adjustment unit 126 of the communication apparatus of the present invention rewrites the value of the window field existing in the TCP header to a smaller value and returns the packet to the original destination of the packet. Forward. Upon receiving this packet, the original destination device subsequently reduces the data transmission rate (window size) by TCP general flow control. As described above, the destination device controls the transmission rate of transmission data to the low priority communication device, but conversely controls the transmission rate from the low priority communication device to the partner communication device. Data may be generated and transmitted to the low priority communication device.

  3. When the low-priority communication is TCP (Transmission Control Protocol), the adjustment unit 126 of the communication apparatus according to the present invention uses one Ack packet having a sequence number included in the TCP header of the Ack (Acknowledgement Response) packet. One or more are generated and transferred to the original destination of the packet. When the device that is the original destination receives these Ack packets, the data transmission rate (window size) is subsequently lowered by TCP flow control.

  4). When the low-priority communication is TCP (Transmission Control Protocol), the adjustment unit 126 of the present invention delays for a certain time from receiving to transferring to the original destination. At this time, the transmission timing of the next packet is similarly delayed by the TCP flow control, so that the data transmission rate is lowered thereafter.

  5. The path change control unit 842 of the communication apparatus of the present invention may further include a QoS value holding unit (not shown) that holds a QoS value set to hold the quality of high priority communication. Then, the route change control unit 842 calculates a value indicating the quality of the higher priority communication based on the traffic volume of the communication, and compares the calculated value indicating the quality with the QoS value. Here, when the value indicating the calculated quality is smaller than the QoS value, route change control data is transmitted. Therefore, by changing the communication path for low-priority communication according to the deterioration of the quality of high-priority communication, the communication path for high-priority communication can be secured only during the necessary period, The influence on the priority communication can be eliminated. Note that the value indicating the quality of the high priority communication can be obtained from the traffic volume, the application used for the telephone, the value indicating the sound quality, and the like.

<Packet size change control>
Further, in the detailed control after the route change, the QoS of the IP telephone communication can be further improved by performing a process for reducing the packet size of the low priority communication in addition to the priority control described so far.

  The phenomenon that the QoS of the IP telephone communication is lowered when the packet size of the low priority communication is large has already been described as the phenomenon 4 in the “Background Art”, and thus the description thereof is omitted here.

  Methods for reducing the packet size of low-priority communication are broadly divided into (1) a method in which the QoS control device divides and transmits received low-priority communication packets, and (2) a low-priority communication device (for example, PC111). Etc.), there are two types of methods for reducing the size of the packet itself transmitted.

(1) Method of Dividing (Fragmenting) Low-priority Communication Packets Received by QoS Control Device by Coordinator 126 As a method of dividing and transmitting low-priority communication packets received by QoS control device It is easiest to perform IP fragment processing. The IP fragment by a normal router is for dividing the packet into a plurality of packets having a size equal to or smaller than the MTU when the size of the packet transferred by the router exceeds the MTU (Maximum Transfer Unit) of the access line. . However, here, regardless of the MTU value of the access line, for example, a packet of 1500 bytes (IP data size minus IP header 20 bytes is 1480 bytes) and a packet of 300 bytes (IP data size is 280 bytes) Divide into packets. As a result, the time taken for each fragmented packet to be transmitted to the access line (the maximum time that the voice data waits in the router) is 300/1500 = 1/5. Therefore, increase in delay time and fluctuation of IP telephone communication can be suppressed.

  Here, the flow of a packet when an IP fragment occurs will be briefly described with reference to FIG. First, the PC 111 transmits a 1500-byte data packet 2601 as usual. Here, as described above, the destination of the communication path of the PC 111 that is the low priority communication is changed to the first IP telephone 114 that is the high priority communication. Upon receiving the data packet 2601 from the PC 111, the QoS control unit 121 of the first IP telephone 114 of the present invention first performs IP fragment processing. Then, the QoS control unit 121 transmits the plurality of divided data packets 2611 to 2616 to the server 113. In each fragmented data packet 2611 to 2616, a value indicating the positional relationship of each data packet in the original data packet 2601 is set in the fragment offset field of the IP header, as in the case of a normal IP fragment. That is, a value indicating where the head of the data included in each data packet is located from the head of the data of the original data packet 2601 is set. In a fragment packet other than the last fragment packet 2616, a more fragment flag indicating that there is a subsequent fragment packet is set.

  The data dividing method in the present invention may be any method and is not limited to IP fragments. For example, in addition to the division by IP fragment, a method of extracting a TCP data stream from a series of IP packets, dividing the data again into an appropriate size, and sending each as an IP packet, a plurality of IP packets in a data link layer It is also possible to divide the data sequence into data strings (the Ethernet (registered trademark) protocol cannot use this method, but it can be used when a data link protocol capable of such a method is defined in the future). .

  In addition, when the fragment prohibition bit of the IP header is set, or in the provisions regarding IP fragments in IPv6, it is prohibited to perform fragmentation in the relay device. However, even if IP fragmentation is performed against these rules, it is possible to continue communication normally, and the present invention includes the case where IP fragment is performed for these packets.

(2) A method of reducing the size of a packet transmitted by a low-priority communication source device As a method of reducing the packet size at the time of transmission by a low-priority communication source device, an MSS included in a TCP SYN packet There are a method of changing (Maximum Segment Size), a method of changing an MTU (Maximum Transfer Unit) of a low-priority communication device using an ICMP destination unreachable Fragment Needed packet, and the like. However, the present invention is not limited to these methods.

(2-1) Changing MSS First, a method for changing the MSS of a SYN packet will be described. FIG. 28 shows a format of a TCP SYN packet with the MSS option. MSS is a value defined in TCP and is the maximum data size when data is divided. The MSS is a value defined for storing data received from an application in each IP packet. The MSS is determined as follows. First, a SYN packet is transmitted from both devices at the start of a TCP session, and the value of the MSS field included in the SYN packet is compared. The MSS is determined by selecting the smaller MSS among these.

  A procedure for using this mechanism to reduce the size of a packet transmitted by a transmission source device of low priority communication will be described with reference to FIG. Here, as described above, the destination of the communication path of the PC 111 that is the low priority communication is changed to the first IP telephone 114 that is the high priority communication.

  First, the PC 111 transmits a SYN packet 2701 to the server 113 when starting a TCP session. At this time, the PC 111 sets 1460 as the value of the MSS field (a value obtained by subtracting the IP header (20 bytes) and the TCP header (20 bytes) from the Ethernet MTU size 1500 bytes is often used).

  As the route is changed as described above, the first IP telephone 114 receives the SYN packet transmitted from the PC 111 to the server 113. Then, the adjustment unit 126 in the QoS control unit of the first IP telephone 114 changes the value of the MSS field of the SYN packet to a smaller value, for example, 260, and transfers it to the server 113 (S2711). At this time, the QoS control unit also needs to correct the checksum field in the TCP header.

  Next, the server 113 compares the value 260 of the MSS field of the received SYN packet with the value of MSS (1460 here) set in the SYN packet transmitted by itself. Then, the server 113 sets 260, which is the smaller value, as the MSS value of the server 113 (S2712).

  Next, the server 113 transmits a SYN packet to the PC 111. At this time, the server 113 sets 1460 as the value of the MSS field. Since the path change has been performed as described above, the first IP telephone 114 receives the SYN packet from the server 113. The adjustment unit 126 of the first IP telephone 114 changes the value of the MSS field of the received SYN packet to a smaller value, for example, 260, and forwards it to the PC 111 (S2713). At this time, the checksum field in the TCP header also needs to be corrected.

  Next, the PC 111 that has received this compares the MSS field value 260 of the received SYN packet with the MSS value 1460 set in the SYN packet transmitted by itself. The smaller value 260 is set as the MSS value of the PC 111 (S2714). Thereafter, the size of the TCP packet transmitted by the PC 111 and the server 113 is 300 bytes (TCP data 260 bytes + TCP header 20 bytes + IP header 20 bytes).

  In this example, the MSS field of the SYN packet transmitted by both apparatuses is rewritten. However, when only the size of the packet transmitted from the PC 111 is desired to be reduced, only S2713 is performed without performing S2711. Further, if only S2711 is performed without performing S2713, the size of the packet transmitted from the server 113 can be reduced.

(2-2) Change of MTU Next, a method of using the ICMP destination unreachable fragmented packet (see FIG. 30) will be described. In this method, the device is notified that the packet needs to be divided and fragmented, and the device sets the packet size based on the notification.

  FIG. 30 shows a format of an ICMP destination unreachable fragmented packet. As the MTU value set in each communication apparatus, the maximum transmission data size defined in the data link layer protocol used in the transmission line is normally set. However, when a communication device such as the PC 111 receives the ICMP destination unreachable fragmented packet, the MTU value set in the transmission packet by the PC 111 is overwritten by the MTU value included in the MTU field (2933). When the MTU value of the communication device is changed, the size of the IP packet transmitted by the communication device thereafter becomes equal to or smaller than the changed MTU value.

  A procedure for reducing the MTU of the low-priority communication apparatus using the ICMP destination unreachable fragmentation packet will be described with reference to FIGS. 30 and 31. FIG. First, the PC 111 transmits a 1500-byte data packet 2801 according to a normal MTU value 1500. As the route is changed as described above, the first IP telephone 114 of the present invention receives this packet from the PC 111. The adjustment unit 126 of the QoS control unit of the first IP telephone 114 obtains information (data of at least 64 bytes from the beginning of the received packet) to be set in the part 2934 of the fragmented packet requiring ICMP destination unreachable in FIG. (S2811). The received data is transferred as it is to the server 113 as a data packet 2802.

  Next, the adjustment unit 126 of the QoS control unit of the first IP telephone 114 generates an ICMP destination unreachable fragmented packet 2803 and transmits it to the PC 111 (S2812). The IP address of the first router 112 is set as the transmission source IP address of the IP header 2931 of this ICMP destination unreachable fragmented packet, and the IP address of the PC 111 is set as the destination IP address. In the ICMP header 2932, a predetermined value is set to indicate that this packet is a destination unreachable fragmented packet. Also, as the MTU value, for example, “576” is set as the packet size transmitted by the low priority communication apparatus. Furthermore, the received packet information acquired in S <b> 2811 may be set in a part 2934 of the received packet.

  Next, the PC 111 that has received the ICMP destination unreachable fragmentation packet 2803 changes its own MTU value to the designated 576 (S2813). Thereafter, the maximum size of the data packet 2804 transmitted by the PC 111 is 576 bytes. Thereby, the size of the data packet of the PC 111 transferred by the first IP telephone is reduced, and the QoS of IP telephone communication can be improved.

  Note that although 576 is specified as the MTU value here, any value may be used as long as it can secure the QoS of IP telephone communication. However, depending on the implementation of the low-priority communication device, there are many implementations that do not change the MTU value even if an ICMP destination unreachable fragmented packet with an MTU value less than 576 is specified, so it is better to specify 576 or higher. The effect is more certain.

  So far, the method using the ICMP destination unreachable fragmented packet used in the IPv4 network has been described. However, in the case of the IPv6 network, the ICMPv6 packet excessive packet has the same function, and therefore the MTU of the low priority communication apparatus can be changed by using this packet. The same effect can be obtained by specifying the MTU option in the ICMPv6 router notification packet.

  For example, it is assumed that the PC 111 transmits a packet with a fragment prohibition flag that prohibits packet division. In this case, the first IP telephone set 114 that has received this packet cannot divide the received packet due to the fragment prohibition flag. However, as described above, the first IP telephone 114 can change the MTU value of the PC 111 by sending the ICMP destination unreachable fragmentation packet. Therefore, even when a device that receives a packet cannot divide the received packet, the size of the packet can be reduced.

  Further, since the change in the MSS in (2-1) is performed by changing the MSS option in the TCP header, it cannot be used for UDP. However, the method (2-2) for changing the MTU value described above can be applied to both TCP and UDP.

<Others>
Note that <applied environment>, <installation position>, <route change method>, and <at the timing of route change> are the same as those in the first embodiment, and thus are omitted.

  By using the communication device of the present invention that performs the above operation, low priority communication and high priority communication compete, but priority is not replaced without replacing routers in networks where priority control is not performed. The control function can be realized, and the user can easily enjoy real-time communication such as an IP phone without changing the provider.

  The communication device of the present invention further includes a transmission data generation unit that generates transmission data to be transmitted to the counterpart communication device, and when the transmission data is high priority communication data, the selection unit prioritizes the transmission data. It is also possible to select to transmit automatically. Thus, when the communication device itself transmits high-priority transmission data to another communication device, it transmits the high-priority transmission data with priority over the low-priority communication data that needs to be relayed. be able to. In addition, the above-described selection unit may select so as to preferentially transmit high priority communication data among a plurality of received data to be received. Thus, when the communication device receives a plurality of received data from a plurality of communication devices and needs to relay to other communication devices, the received data with the highest priority among these received data is given priority. Can be sent.

(Other embodiment examples)
Each embodiment described in the present invention can also be realized by causing the CPU to execute a program for causing the CPU to execute the above-described processing procedure. In this case, the program may be stored in a recording medium and executed from a storage device (such as a hard disk) of the device that stores the contents, or may be directly executed from the recording medium. The recording medium here refers to a recording medium such as a semiconductor memory such as a ROM, a RAM, or a flash memory, a magnetic disk memory such as a flexible disk or a hard disk, an optical disk such as a CD-ROM, DVD, or BD, or a memory card.

  The functions of the QOS control unit described in each embodiment may be realized as an LSI that is an integrated circuit. The name used here is LSI, but it may also be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

  Further, the method of circuit integration is not limited to LSI, and implementation with a dedicated circuit or a general-purpose processor is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI, or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

  The communication device of the present invention according to the present invention can be applied to a general network in which priority control is not performed, although low priority communication and high priority communication compete. For example, when multiple communications are competing on an access line (such as an ADSL line) in a home Internet connection environment, or a low-speed communication path (such as a wireless section or a power line) in a home LAN or corporate LAN. Applicable.

The network block diagram in 1st Embodiment. The block diagram of the QoS control part and 1st IP telephone in 1st Embodiment. Data format of ARP request / ARP response. The flow of data in the QoS control procedure when using an ARP request. Process and data flow in QoS control procedure when ARP request is used. The QoS control processing flow in a path | route change control part at the time of using an ARP request | requirement. ARP table (1) of the device to be controlled. The ARP table (2) of the device to be controlled. ARP table (3) of the device to be controlled. IP address and MAC address list of each device. The installation position of the communication apparatus of this invention, and the flow of communication after path | route change control in case the communication apparatus of this invention is an independent LAN terminal. QoS control device. Neighbor solicitation packet and neighbor notification packet format. Format of ICMP route change packet. The flow of data in the QoS control procedure when an ICMP path change packet is used. Process and data flow in QoS control procedure when ICMP path change packet is used. The routing table (1) of a control object apparatus. The routing table (2) of a control object apparatus. The network block diagram in 2nd Embodiment. The block diagram of the QoS control part and IP telephone in 2nd Embodiment. Processing and data flow when performing detailed control after route change control. ARP table of the control target device. The routing table of the control target device. Ethernet (registered trademark) frame and IP packet format. The flowchart of the reception process in a low priority communication packet relay process. The flowchart of the transmission process in a low priority communication packet relay process. Detailed operation in packet relay processing (when full-duplex, with buffer). Detailed operation in packet relay processing (when full-duplex, no buffer). Detailed operation in packet relay processing (in case of half duplex). Processing and data flow when performing IP fragmentation in detailed control after route change control. TCP SYN packet format with MSS option. Processing and data flow when changing MSS value of TCP SYN packet in detailed control after route change control. ICMP destination unreachable fragmented packet format. Processing and data flow when ICMP destination unreachable fragmented packet is transmitted in detailed control after route change control. The block diagram of the network of the current home LAN (without IP phone). The network block diagram at the time of adding an IP telephone to the network of FIG. The internal structure figure of the router of FIG. The network block diagram in a prior art example, and the internal structure of a router. Explanatory drawing of the phenomenon in which term priority communication data is waited when the packet size of low priority communication is large.

Explanation of symbols

1, 101: First home 2, 102: Internet 3, 103: First ISP
4, 104: second home 5, 105: second ISP
6, 106: Access line 7, 107: LAN line 11, 111: PC
12, 112: first router 13, 113: server 14, 114: first IP telephone 16, 116: second router
115: Fictitious device 17, 117: Second IP telephone
121, 621: QoS control unit 122: voice data generation unit 123: communication processing unit 131: communication between PC and server 132: communication between IP phone and IP phone 133: PC after route change in the second embodiment Communication between servers 711 QoS control device 841 Priority information holding unit 842 Route change control unit 1021 ARP table of PC 1621 Routing table of PC 1941 Received data processing unit

Claims (23)

A communication device that performs communication via a network in which a plurality of communications with different priorities is performed, and a communication device that controls communication according to the priority,
Priority information holding means for holding priority information related to the priority of each communication;
Based on the priority information, the first control data for changing the communication path of the low priority communication is generated, and the low priority communication device that performs the low priority communication or another communication device via the network A path change control means for transmitting the first control data to a relay device that relays low priority communication performed between them;
A communication apparatus comprising:   2. The communication apparatus according to claim 1, wherein the path change control unit changes a destination of the communication path of the low priority communication included in the first control data to an address that cannot be transmitted. The route change control means changes the destination of the communication route of the low priority communication included in the first control data to an address of a communication device that controls communication according to the priority,
The communication apparatus according to claim 1, further comprising communication control means for controlling output of transmission data from the low priority communication apparatus to the network. The communication control means includes
Analyzing means for analyzing whether or not the transmission destination of at least one received data is its own device, and whether or not the received data is low priority communication data from the low priority device;
Selection means for controlling to select high-priority communication data preferentially over lower-priority communication data whose destination is other than its own device and transmit to the destination according to the analysis result by the analysis means The communication apparatus according to claim 3, further comprising: The communication control means includes
As a result of the analysis by the analyzing means, the source address of low priority communication data whose destination is other than the own device is the address of the own device, and the destination address of the low priority communication data is the low priority before the route change. It further has an adjusting means for performing address rewriting processing for rewriting to the original destination address of the low priority communication data transmitted from the communication device,
The communication apparatus according to claim 4, wherein the adjustment unit transmits low priority communication data after the address rewriting process to the selection unit. As a result of analysis by the analysis means, further includes an upper layer processing unit that processes received data whose destination is the own device,
The analysis means determines whether or not the destination of the received data is its own device by analyzing the IP header of the received data and whether or not the destination is the IP address of its own device,
If the destination of the received data is its own device, send the received data to the higher layer processing unit,
The communication apparatus according to claim 4, wherein, when the destination is other than the own apparatus, the reception data is transmitted to the selection unit.   The communication apparatus according to claim 3, wherein the communication control unit is realized by hardware. The communication control means includes
An adjustment unit for discarding part or all of the low priority communication data;
5. The communication apparatus according to claim 4, wherein the adjustment unit transmits low priority communication data after a part or all of the adjustment unit is discarded to the selection unit. The communication control means includes
An adjustment unit for performing a first adjustment process for adjusting a communication rate of the low priority communication;
The communication apparatus according to claim 4, wherein the adjustment unit transmits low priority communication data after the first adjustment process to the selection unit.   The communication apparatus according to claim 9, wherein the adjustment unit adjusts a transmission rate by adjusting a value of a window field of a TCP header. Further comprising storage means for storing the low priority communication data;
When the low-priority communication data is a TCP data packet or a TCP ACK packet, the adjustment unit accumulates the low-priority communication data for a certain period of time using the accumulation unit, and then stores the low-priority communication data in the selection unit. The communication device according to claim 9, wherein the communication device transmits. The communication control means includes
An adjustment means for dividing the transmission data from the low priority communication device into a plurality of data using the first division method;
The communication apparatus according to claim 4, wherein the adjustment unit transmits data divided into a plurality of pieces using the first division method to the selection unit.   The communication apparatus according to claim 12, wherein the first division method divides into IP fragments. The communication control means includes
Based on the communication data received from the low priority communication device, communication data from the low priority communication device to the communication device of the counterpart of the low priority communication device or communication of the counterpart of the low priority communication device An adjustment unit for generating third control data for controlling the size of communication data from the device to the low priority communication device and transmitting the third control data to the low priority communication device or the counterpart communication device; The communication apparatus according to claim 4, wherein the communication apparatus is characterized.   15. The third control data is a TCP SYN packet, and the adjustment unit generates a SYN packet in which an MSS value included in the received SYN packet is changed to a desired value. Communication equipment.   The third control data is an ICMP destination unreachable fragmentation required packet, and the adjustment means includes a part of data included in a packet transmitted from the low-priority communication device before, and a desired MTU value The communication apparatus according to claim 14, wherein an ICMP destination unreachable fragmentation packet including the packet is generated.   The path change control means changes the address of the communication path for the low priority communication to the address of the own apparatus in the first control data, and the communication path for the high priority communication based on the priority information. Second control data is generated to change the destination, and the destination of the communication path of the high priority communication in the second control data is changed to the address of the own device, and the second control data is transmitted to the high priority communication device. The communication apparatus according to claim 1, wherein data is transmitted.   2. The communication apparatus according to claim 1, wherein the first control data transmitted by the path change control unit is one of an ARP request packet, an ARP response packet, an ICMP path change packet, and an ICMPv6 neighbor search packet. . Further comprising detection means for detecting whether communication via a network is performed by the high priority communication device;
The route change control means transmits the first control data to the low-priority communication device or the relay device only when communication by the high-priority communication device is performed. The communication apparatus as described in. QoS value holding means for holding a QoS value set to hold high priority communication quality,
The detection means further calculates a value indicating the quality of high priority communication, compares the calculated quality value with the QoS value,
When the value indicating the calculated quality is smaller than the QoS value, the path change control means transmits the first control data to the low priority communication apparatus or the relay apparatus. The communication device according to claim 19. In a plurality of communications with different priorities performed via a network, a computer-readable recording medium that records a priority control program executed by a control device that controls communication according to the priority,
Priority information holding means for holding priority information related to the priority of each communication; and
Based on the priority information, the first control data for changing the communication path of the low priority communication is generated, and the low priority communication device that performs the low priority communication or another communication device via the network A computer-readable recording medium having recorded thereon a priority control program that causes a computer to function as a path change control means for transmitting the first control data to a relay device that relays low priority communication performed between them. In a network in which a plurality of communications with different priorities are performed, an integrated circuit that controls communications according to the priorities,
Priority information holding means for holding priority information related to the priority of each communication;
Based on the priority information, the first control data for changing the communication path of the low priority communication is generated, and the low priority communication device that performs the low priority communication or another communication device via the network A path change control means for transmitting the first control data to a relay device that relays low priority communication performed between them;
An integrated circuit comprising: In a communication system in which a communication device that controls communication according to communication priority and a plurality of communication devices having different priorities are connected,
A communication device that controls communication according to the priority,
Priority information holding means for holding priority information related to the priority of each communication;
Based on the priority information, the first control data for changing the communication path of the low priority communication having a low priority is generated, and the low priority communication apparatus or the network that performs the low priority communication is used. Path change control means for transmitting the first control data to a relay device that relays low priority communication performed between other communication devices;
The low-priority communication device or a relay device that relays low-priority communication performed between other communication devices via the network includes the first control data from a communication device that controls communication according to the priority. And changing the communication path of the low-priority communication.

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