JP2004320673A - Packet transfer device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To raise the efficiency of packet transfer by a packet transfer device for transferring a packet. <P>SOLUTION: The packet transfer device is provided with packet transfer means 2, 3, 11, 12 having functions of transferring packets by two or more different transfer modes, and a packet transfer mode changeover means 13 changes packet transfer modes by the transfer means 2, 3, 11, 12. As one example, a processing mode 1 for performing transfer by a low order layer 11 and a processing mode 2 for performing transfer by a high order layer are changed, depending on whether an information transmission rate in a transmission-side wireless section is larger or smaller than a predetermined threshold. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a packet transfer device for transferring a packet, and more particularly, to a packet transfer device for improving the efficiency of packet transfer by switching a transfer mode.
[0002]
[Prior art]
For example, in the field of information communication, packet communication is performed, and a packet transfer device that transfers a packet is used.
Various studies have been made on such a packet transfer device (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-2002-281075
[0004]
[Problems to be solved by the invention]
However, the conventional packet transfer device is still insufficient in transferring a packet in response to a change in the communication state of the packet, for example, and further development has been required.
The present invention has been made in view of such conventional circumstances, and provides, for example, a packet transfer device capable of improving the efficiency of packet transfer even when the packet communication situation changes. With the goal.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a packet transfer device according to the present invention transfers a packet as follows.
That is, a packet transfer unit having a function of transferring a packet in a plurality of different transfer modes is provided, and the packet transfer mode switching unit switches the transfer mode in which the packet is transferred by the packet transfer unit.
[0006]
Therefore, the transfer mode for transferring the packet is switched and the packet transfer is performed, so that the efficiency of the packet transfer can be improved. Further, for example, even when the communication status of a packet changes, the efficiency of packet transfer can be improved by switching the transfer mode according to the change in the communication status.
[0007]
Here, various types of packets may be used.
Various devices may be used as the communication device serving as a packet transfer source and the communication device serving as a packet transfer destination. The packet transfer device receives, for example, a packet transmitted from a transfer source communication device, and transmits the received packet to a transfer destination communication device.
[0008]
Also, various numbers may be used as the number of the plurality of different transfer modes.
Further, various transfer modes may be used.
Further, the packet transfer means has a function of transferring a packet according to each transfer mode switched by the packet transfer mode switching means.
Further, the packet transfer unit may be configured as, for example, a unit that executes all the processes of the packet transfer, or may be configured as a unit that executes a part of the processes of the packet transfer.
[0009]
Various methods may be used for switching the transfer mode for transferring the packet. For example, a method for switching the transfer mode according to the communication state of the packet or a change thereof may be used.
As the communication state of the packet, various things may be used.For example, regarding one or both of a line for transmitting a packet and a line for receiving a packet, using a communication speed, a communication amount, a communication quality, and the like. Is possible.
[0010]
Hereinafter, a configuration example according to the present invention will be further described.
As one configuration example, the packet transfer device according to the present invention uses, as a first transfer mode, a transfer mode in which received packets are transmitted in the order in which they are received.
As one configuration example, the packet transfer device according to the present invention uses, as a second transfer mode, a transfer mode in which received packets are transmitted in the order in which the packets are received and rearranged based on a predetermined rule.
Here, various rules may be used as the predetermined rule. For example, a rule based on priority can be used.
[0011]
As one configuration example, in the second transfer mode, packets are transferred based on the priority corresponding to the received packet.
Specifically, as an example, in the second transfer mode, a packet is transferred based on a priority specified by predetermined information included in a received packet.
Further, as an example, the packet transfer device includes a predetermined information priority correspondence storage means for storing a correspondence between predetermined information and a priority, and in the second transfer mode, the predetermined information priority correspondence storage means Referring to the contents, the packet is transferred based on the priority corresponding to the predetermined information included in the received packet.
[0012]
Here, various information may be used as the predetermined information.
As an example, as the predetermined information, information on the port number of the transmission source device or the transmission destination device, information on the MAC address, and the like can be used.
In addition, as an example, a priority can be used as the priority.
Further, the predetermined information priority correspondence storage means can be configured using, for example, a memory for storing information.
[0013]
Also, as an example, as the high-priority packet, a packet that requires real-time properties, such as a packet for transmitting information such as video distribution or IP telephone, can be used. As a low-priority packet, A packet that does not require real-time properties, such as a packet transmitting information such as file download, can be used. Note that various information such as text, voice, and image can be used as the information.
Further, as the priority of the packet, various other specifications may be used.
[0014]
As one configuration example, in the packet transfer device according to the present invention, the packet is transferred by the function of the lower layer in the first transfer mode, and the packet is transferred by the function of the upper layer in the second transfer mode.
Here, various layers may be used as the lower layer and the upper layer, respectively.
[0015]
As one configuration example, in the packet transfer device according to the present invention, when switching from a transfer mode by the upper layer (for example, the second transfer mode) to a transfer mode by the lower layer (for example, the first transfer mode), The packet held in the upper layer is transferred to the lower layer, and the packet is transferred by the lower layer.
[0016]
As one configuration example, in the packet transfer device according to the present invention, the packet transfer mode switching unit switches the packet transfer mode based on the information transmission speed on the line that transmits the packet.
Here, various lines may be used as the line for transmitting the packet. For example, a wireless line may be used, or a wired line may be used.
[0017]
Similarly, various lines may be used as a line for receiving a packet. For example, a wireless line may be used, or a wired line may be used.
Further, as the line for receiving the packet and the line for transmitting the packet, for example, the same line may be used, or different lines may be used.
As a line for receiving a packet or a line for transmitting a packet, for example, one line may be used, or a plurality of lines may be used.
[0018]
Specifically, as an example, the packet transfer mode switching unit switches to a transfer mode by a lower layer (for example, a first transfer mode) when the information transmission speed on the line transmitting the packet exceeds a predetermined threshold. If the information transmission rate on the line for transmitting the packet is lower than the predetermined threshold, the mode is switched to the transfer mode by the upper layer (for example, the second transfer mode).
[0019]
Therefore, when the information transmission speed is high, packets can be transferred at high speed by, for example, the first transfer mode of the lower layer, and when the information transmission speed is low, for example, the second transfer by the upper layer can be performed. Higher QoS (Quality of
Service).
[0020]
Here, when the information transmission speed on the line for transmitting the packet is equal to the predetermined threshold, for example, the transfer mode may be switched in the same manner as the case where the information transmission speed exceeds the predetermined threshold, or, The switching of the transfer mode may be performed in the same manner as in the case of, or another mode may be used.
[0021]
As one configuration example, in the packet transfer device according to the present invention, the packet transfer mode switching unit switches the packet transfer mode based on a signal input from an external device.
Here, various devices may be used as the external device.
Various signals may be used as a signal input from an external device. For example, a signal including information referred to for switching a transfer mode or a signal including an instruction for switching a transfer mode Etc. can be used.
[0022]
As another configuration example, in the packet transfer device according to the present invention, the packet transfer mode switching unit switches the packet transfer mode based on a signal input from inside the packet transfer apparatus.
Here, various processing units may be used as an internal processing unit that outputs a signal to the packet transfer mode switching unit.
[0023]
Hereinafter, a configuration example according to the present invention will be further described.
As one configuration example, in the present invention, a packet transfer device that transfers a packet by transmitting a received packet has a packet receiving unit that receives the packet and a function of transferring the packet in a plurality of different transfer modes. The packet transmission unit includes a packet transmission unit that transmits a packet received by the packet reception unit according to the transfer mode that is switched, and a packet transfer mode switching unit that switches a transfer mode used by the packet transmission unit.
[0024]
Here, in the present configuration example, for example, the packet transfer unit includes a packet reception unit and a packet transmission unit.
Also, various devices may be used as the communication device for transmitting the packet received by the packet receiving unit and the communication device for receiving the packet transmitted by the packet transmitting unit.
[0025]
As one configuration example, in the packet transfer device according to the present invention, the packet transfer means includes a first layer function unit and a second layer function unit. The second layer is a higher layer than the first layer.
The functional unit of the first layer includes a receiving buffer unit that stores a packet received by the packet receiving unit, and a transmitting buffer unit that stores a packet to be transmitted. Has a function of transferring packets in a first transfer mode of transmitting received packets in the order of reception by reading out the packets stored in the reception buffer in the order received and storing them in the transmission buffer. ing.
[0026]
The functional unit of the second layer reads a packet stored by a plurality of packet queue units corresponding to the respective priorities and a packet storage unit of the functional unit of the first layer, and stores the read packet in the packet. Packet classifying means for storing in a packet queue means corresponding to the priority of a packet queue, and reading out packets stored in a plurality of packet queue means in a form based on the priority corresponding to each packet queue means, and And a packet reading means for storing the packet in the transmission buffer means of the first layer, wherein the function unit of the second layer reads the packet stored in the reception buffer means of the function unit of the first layer, and stores the read packet in the packet. The received packets are stored in the transmission buffer means of the functional unit of the first layer in order based on the priority. And has a function of transferring the packet by the second transfer mode in which transmission in an order based on the priority.
The packet transfer mode switching means switches between the first transfer mode and the second transfer mode.
[0027]
Here, various layers may be used as the first layer and the second layer, respectively.
Further, as the functional units of the first layer and the functional units of the second layer, those having various configurations may be used.
In addition, the reception buffer unit, the transmission buffer unit, and each packet queue unit can be configured using, for example, a buffer memory that temporarily stores packets.
[0028]
Also, various numbers may be used as the number of the plurality of packet queue units.
Various priorities corresponding to the respective packet queue means may be used. Specifically, for example, a configuration is used in which different priorities are set for all packet queue units, or a configuration is used in which at least two different priorities are set for different packet queue units.
[0029]
As one configuration example, in the present invention, the packet transfer device includes a wireless communication unit inside or outside. Further, the packet transmitting unit outputs the packet to be transmitted to the wireless communication unit, and the wireless communication unit wirelessly transmits the packet input from the packet transmitting unit. The wireless communication unit notifies the packet transfer mode switching unit of information on the speed at which the packet is wirelessly communicated.
[0030]
Here, for example, the wireless communication unit may be configured and provided as an internal function of the packet transfer device, or may be configured and provided as a function of an external device different from the packet transfer device. .
Various information may be used as the information on the speed at which the packet is wirelessly communicated. For example, information that specifies the information transmission speed at which the packet is wirelessly transmitted may be used.
[0031]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment according to the present invention will be described with reference to the drawings.
First, the background of the present invention will be described. Note that all items described as the background of the present invention are not necessarily the prior art.
In recent years, with the spread of the Internet and low-cost IP (Internet Protocol) communication networks, the use of IP in networks has been progressing. In an IP network, data is delivered from a source to a destination (destination) using an IP protocol.
[0032]
IP is a network layer protocol of OSI (Open System Interconnection) 7 layer, and upper layer protocol is TCP (Transmission Control Protocol) or UDP (User Datagram Protocol) which is a transport layer protocol, and TCP and UDP are TCP. It is responsible for mediating IP and application programs.
[0033]
There are a data link layer and a physical layer protocol as lower protocols of the IP, for example, Ethernet (registered trademark) defined by IEEE802.3 and wireless LAN (Local Area Network) defined by IEEE802.11. . The wireless LAN technology is also applied to wireless access for realizing a subscriber network wirelessly. In an IP network, various applications such as a WEB access, an IP telephone, and a video conference are executed over a wireless system and a wired system. I have.
[0034]
The applications include applications that require real-time properties such as video distribution and IP phones, and applications that do not require real-time properties such as file download. In IP networks, in order to deliver time-critical data such as audio and video to a destination within a certain period of time, priority control technology is applied that classifies transmission data by traffic type within the network and transfers the data in descending order of priority. ing. As priority control techniques in the conventional IP network, MPLS (Multi Protocol Label Switching) and DiffServ (Differentiated Services) at the network layer level, and IEEE 802.1D at the data link layer level are known.
[0035]
IEEE 802.1D is a priority control technology in a wired LAN. For example, a label indicating a priority is added to a header portion of an Ethernet (registered trademark) frame, and queuing in consideration of the priority is performed in a bridge device. Realizes priority control. In IEEE 802.1D, seven traffic classes of (1) Network Control, (2) Voice, (3) Video, (4) Controlled Load, (5) Excellent Effort, (6) Best Effort, and (6) Background are provided. , Priority is set for each traffic.
[0036]
(1) Network Control is traffic necessary to maintain the network infrastructure, and is handled with the highest priority. (2) Voice and (3) Video are traffics with limited delay time and jitter, and are handled with the next highest priority. In the following, priority levels are set in the order of (4) Controlled Load, (5) Excellent Effort, (6) Best Effort, (7) Background, and normal LAN traffic such as e-mail and WEB access is (6) Best Eformat.
[0037]
On the other hand, in the communication in the wireless section, a communication system using an adaptive modulation scheme that performs high-speed communication when the propagation path condition is good and performs low-speed communication when the propagation path condition deteriorates is conceivable. In a system in which an adaptive modulation scheme is applied to wireless section communication, an information transmission rate in a wireless section changes according to a propagation path condition. Therefore, it is necessary to perform QoS control in a wireless section so that a required network environment can be maintained even if the information transmission rate in the wireless section changes.
[0038]
However, when the conventional QoS control technology in a wired LAN is applied to a wireless communication system in which adaptive modulation technology is applied to a wireless section, a transmitter of the wireless device reads a header of transmission data and a label added to the transmission data and reads a packet. And the processing time is increased, resulting in an increase in transmission delay time and a decrease in throughput. When the information transmission rate in the wireless section is higher than the information transmission rate of data input to the transmission side of the wireless device, the wireless device does not need to perform QoS control because transmission latency does not occur in principle. Regardless, since the classification process is always performed, a high-speed processor is required, and there has been a problem that the device price is increased.
[0039]
Next, a packet transfer device according to an embodiment of the present invention will be described.
FIG. 1 shows a configuration example of the packet transfer device of the present embodiment.
The packet transfer device of the present example includes a transfer control unit 1, a reception unit 2, and a transmission unit 3.
The transfer control unit 1 includes a lower layer (functional unit thereof) 11, an upper layer (functional unit thereof) 12, and a switching control unit 13.
[0040]
The lower layer 11 includes a reception buffer 21 for storing a packet received from the reception unit 2 and a transmission buffer 22 for transmitting the packet to the transmission unit 3.
The upper layer 12 includes a classification processing unit 31 for classifying packets received from the lower layer 11, a queue unit 32 having a plurality of n class-specific queues Q1 to Qn, and a queue unit of the queue unit 32. A packet reading unit 33 for reading packets from Q1 to Qn is provided.
[0041]
Here, in this example, the queues Q1, Q2,..., And the queues Qn have the highest priority, that is, the queues Q1 have the highest priority and the queues Qn have the lowest priority. ing.
[0042]
Further, in this example, the reception buffer 21 has an area for storing one packet, and the transmission buffer 22 has an area for storing a plurality of packets. Store and output. In other words, in the transmission buffer 22, the packet stored at the first storage position is the first input packet, and the packet stored at the last storage position is the last input packet.
Further, in this example, each of the queues Q1 to Qn has an area for storing a plurality of packets, and stores and outputs input packets from the top in the order of input.
[0043]
Further, the packet transfer device of the present example is applied to a wireless communication system, and is applied to data transmission in the wireless communication field.
FIG. 2 shows a configuration example of a wireless communication system using the packet transfer device of the present example.
In the example shown in the figure, a packet transfer device 41 and a wireless device 42 are connected, and the packet transfer device 41 outputs a packet input from the outside (not shown) to the wireless device 42, and the wireless device 42 The transmitted packet is transmitted wirelessly from the antenna 43. Further, the wireless device 42 outputs information specifying the information transmission speed in the wireless section to the packet transfer device 41.
[0044]
First, an outline of an example of the overall operation performed by the packet transfer device of the present example will be described.
In this example, a processing mode 1 in which transfer is performed by the lower layer 11 and a processing mode 2 in which transfer is performed by the upper layer 12 are provided, and an operation example in which the switching control unit 13 switches between the two processing modes 1 and 2 is shown.
The receiving unit 2 receives a packet transmitted from a transfer source device (not shown). The packet received by the reception unit 2 is stored in the reception buffer 21 of the lower layer 11 of the transfer control unit 1.
[0045]
In the lower layer 11, processing is switched in accordance with a processing mode instruction from the switching control unit 13.
Specifically, in the lower layer 11, when the processing mode 1 is instructed, the received packet stored in the reception buffer 21 is stored in the last storage position of the transmission buffer 22. Further, in the lower layer 11, when the processing mode 2 is instructed, the received packet stored in the reception buffer 21 is sent to the upper layer 12.
[0046]
In the upper layer 12, the classification processing unit 31 reads the header information or the like of the packet received from the lower layer 11, and corresponds the packet to the priority of each packet in the queues Q1 to Qn for each class. Store in one of them. In addition, the packet reading unit 33 reads packets from the queues Q1 to Qn for each class according to a rule considering QoS such as priority, and stores the read packets in the last storage position of the transmission buffer 22 of the lower layer 11.
[0047]
In the lower layer 11, the data of the packet is read out sequentially from the head storage position of the transmission buffer 22 and sent to the transmission unit 3, and the packet sent to the transmission unit 3 is transferred from the transmission unit 3 to the device (in this example, the transfer destination). , Wireless device 42).
The packet transfer device of the present example performs packet transfer by operating as described above.
[0048]
Next, an example of an operation performed by the transfer control unit 1 which is a characteristic part of the packet transfer device of the present example will be described.
FIG. 3 shows an example of a procedure of a reception process performed by the transfer control unit 1.
When the packet arrives at the receiving unit 2, the transfer control unit 1 receives a control signal for notifying the completion of the packet reception from the receiving unit 2 (step S1). Then, the transfer control unit 1 reads out the packet received from the reception unit 2 and stores the packet in the reception buffer 21.
[0049]
Next, the lower layer 11 determines the processing mode (step S2), and if the processing mode 1 is set, stores the packet stored in the reception buffer 21 in the last storage position of the transmission buffer 22. (Step S3).
On the other hand, when the processing mode 1 is not set, that is, when the processing mode 2 is set, the lower layer 11 sends the packet stored in the reception buffer 21 to the upper layer 12 (step S4). .
In the upper layer 12, the classification processing unit 31 reads the header information and the like of the packet received from the lower layer 11, and performs queuing of the queues Q1 to Qn for each class based on the read result (step S5).
[0050]
Here, the processing modes 1 and 2 are instructed by the switching control unit 13.
The switching control unit 13 determines a processing mode based on an external signal, and issues an instruction to the lower layer 11 and the upper layer 12 to set the processing mode 1 or the processing mode 2.
[0051]
In the present example, as shown in FIG. 2 above, a wireless communication system is configured by connecting the packet transfer device 41 to the wireless device 42. As an example, the switching control unit 13 outputs a wireless signal as an external signal. A signal including information on the information transmission speed in the wireless section is input from the device 42. Then, the switching control unit 13 specifies the wireless section information transmission rate from the input information of the wireless section information transmission rate, and when the specified wireless section information transmission rate is smaller than a predetermined threshold (when it is slow). In the meantime, while a signal designating the processing mode 2 is notified to the lower layer 11 and the upper layer 12, if the specified wireless section information transmission rate is higher than the predetermined threshold (if faster), the processing mode 1 is notified to the lower layer 11 and the upper layer 12.
[0052]
In this example, the configuration example in which the information of the wireless section information transmission rate is input to the switching control unit 13 and the processing mode is switched based on the wireless section information transmission rate has been described. A configuration in which the processing mode is switched based on the input and the other information may be used. As the other information, for example, information on the error rate of the transmission path or C / N (Carrier to Carrier) of the transmission path may be used. Noise ratio) can be used.
[0053]
FIG. 4 shows an example of a procedure of a transmission process performed by the transfer control unit 1. When the transmission control unit 13 is notified by the control signal that the transmission unit 3 is ready to transmit (transmission is possible) (step S11), the upper layer 12 determines the processing mode (step S12) and performs processing. When the mode 2 is set, the packet reading unit 33 reads packets to be transmitted from the queues Q1 to Qn for each class of the upper layer 12 in consideration of QoS such as priority, and reads the read packets. Is stored in the last storage position of the transmission buffer 22 of the lower layer 11 (step S13).
[0054]
On the other hand, when the processing mode 1 is set, the upper layer 12 does not perform any processing.
Then, regardless of which processing mode 1 or 2 is set, the packets are read out in order from the top of the transmission buffer 22 of the lower layer 11 and sent to the transmission unit 3 (step S14).
The transmission unit 3 transmits the packet received from the transfer control unit 1 and, when the transmission of one packet is completed, notifies the transfer control unit 1 that the transmission is possible by a control signal.
As described above, the packet transfer device of the present example transfers a packet.
[0055]
Here, the queues Q1 to Qn for each class are queues corresponding to the number of classes to be classified by the classification processing unit 31. When the queue length of any of the queues Q1 to Qn becomes larger than a predetermined length, the classification processing unit 31 performs processing such as discarding the packets stored in the queues Q1 to Qn. Do.
[0056]
Further, when the packet reading unit 33 is instructed to read the packet by the upper layer 12, the packet reading unit 33 reads the packet from the queues Q1 to Qn for each class in consideration of the QoS such as the priority.
Various methods may be used as a packet reading method in consideration of QoS such as priority. For example, as a generally known method, packets are read from queues Q1 to Qn in order of priority. (Queued fair queuing) system that performs readout in a round-robin manner for each of queues Q1 to Qn, or a transmittable amount for each of queues Q1 to Qn, which is within a specified amount. For example, a CBQ (Class-Based Queuing) method for performing reading can be used.
[0057]
FIG. 5 shows an example of a procedure of a process performed by the transfer control unit 1 when the processing mode is switched due to a change in the wireless section information transmission speed.
In this example, when the mode is switched from the processing mode 2 to the processing mode 1, since the subsequent packet transmission is performed only from the lower layer 11, the packets remaining in the queues Q1 to Qn of the upper layer 12 are not left behind. Perform processing for transmission.
[0058]
Specifically, when the transfer control unit 1 switches from the processing mode 2 to the processing mode 1 (step S21), the transfer of the packet considering the QoS such as the priority from the queues Q1 to Qn for each class of the upper layer 12 is performed. Reading is performed, and the read packet is stored in the last storage position of the transmission buffer 22 of the lower layer 11. The transfer control unit 1 executes this process until the queues Q1 to Qn for each class of the upper layer 12 become empty.
[0059]
When the mode is switched from the processing mode 1 to the processing mode 2, since the packets are transmitted from the transmission buffer 22 of the lower layer 11 in order from the head, the transfer of the packet from the lower layer 11 to the upper layer 12 is performed. It is not necessary.
[0060]
Next, an example of processing performed by the classification processing unit 31 will be described.
As an example, the classification processing unit 31 can perform processing using a method defined by IEEE 802.1D. Specifically, a label indicating a priority included in transmission data is read and read. The queues are queued in the queues Q1 to Qn for each class based on the label. This method is effective, for example, when a label indicating a priority is added to input data (transmission data). However, when such a label is not added, priority control can be performed. Can not. Further, the classification processing unit 31 can perform the classification by referring to the TOS (Type Of Service) field of the IP header like DiffServ.
[0061]
As another example, the classification processing unit 31 can perform a process of analyzing information included in header information of input transmission data and determining a priority.
Here, as a specific example, a method of analyzing the information of the port number included in the header information and determining the priority will be described.
[0062]
FIG. 6A shows an image of communication between computers, showing a server 51, a client 52, and a transmission line 53 connecting these.
The server 51 has http, telnet, snmp, TCP, UDP, IP, and lower-level protocols.
The client 52 has a Web browser, telnet, snmp, TCP, UDP, IP, and lower protocols.
[0063]
FIG. 6B shows an example of the IP packet.
The IP packet shown in FIG. 3B is composed of an IP header including information of a source IP address, a destination (destination) IP address, and a protocol number (a TCP number in the example of FIG. 3B). It is composed of a TCP header including information on a port number and a destination port number, and data.
[0064]
For example, when the client 52 wants to view a page on the server 51 with a Web browser, an IP packet as shown in FIG. 6B is transmitted from the client 52 to the server 51.
In this case, it is possible to identify the application that transmits or receives the IP packet based on the port number included in the TCP header of the IP packet, and to apply based on the protocol number included in the IP header of the IP packet. It is possible to identify which protocol is present.
[0065]
For example, the port number is 80 for http, 23 for telnet and 21 for ftp, and the protocol number is 6 for TCP and 17 for UDP.
FIG. 7A shows a detailed example of the format of the TCP header, FIG. 7B shows a detailed example of the format of the UDP header, and FIG. A detailed example of the format of the IP header is shown.
[0066]
The TCP header includes a source port number, a destination port number, a sequence number, an acknowledgment number, an offset, a reservation, a code bit, a window size, a checksum, an emergency pointer, an option, Contains padding information.
The UDP header includes a source port number, a destination port number, a packet length, and checksum information.
The IP header includes a version, a header length, a service type, a packet length, an identifier, a flag, a fragment offset, a lifetime, a protocol number, a header checksum, a source IP address, and a destination. The IP address, options, and padding information are included.
[0067]
The classification processing unit 31 has a port number-priority correspondence table that stores the correspondence between port numbers and priorities stored in a memory or the like.
FIG. 8 shows an example of the contents of such a port number-priority correspondence table, in which a plurality of port numbers (such as "6000") correspond to the corresponding priorities (such as "7"). It is attached and stored.
[0068]
Further, the classification processing unit 31 determines the protocol number included in the IP header of the input transmission data (transmission frame), and determines the applied protocol. Then, the classification processing unit 31 reads the source port number from the header information of the applied protocol, and if the read source port number is registered in the port number-priority correspondence table, The transmission data is queued in a transmission queue (one of queues Q1 to Qn) having a priority corresponding to the registered port number. On the other hand, if the read source port number is not registered in the port number-priority correspondence table, the classification processing unit 31 stores the transmission data in the transmission queue of the default priority (any of the queues Q1 to Qn). C).
[0069]
As described above, the upper layer 12 performs the operation of determining the priority corresponding to the port number included in the transmission data input from the lower layer 11 as the priority of the transmission data. Priority control of transmission data can be performed according to the number.
[0070]
For example, when the frame of the transmission data is an Ethernet (registered trademark) frame, an Ethernet (registered trademark) MAC header is added before the above-described IP header, and a destination (transmission destination) is added to the MAC header. The address information of the terminal and the address information of the source terminal are included.
In such a case, the classification processing unit 31 can perform priority control of transmission data using the MAC address.
[0071]
In other words, the classification processing unit 31 has a MAC address-priority correspondence table that stores the correspondence between MAC addresses and priorities stored in a memory or the like.
FIG. 9 shows an example of the contents of such a MAC address-priority correspondence table, in which a plurality of MAC addresses ("11-22-33-00-00-01" etc.) and the corresponding priority The degree (“7” or the like) is stored in association with the degree.
[0072]
Further, the classification processing unit 31 analyzes the MAC header included in the transmission data, refers to the MAC address-priority correspondence table, and determines whether the destination MAC address or the transmission source MAC address of the transmission data corresponds to the MAC address-priority correspondence. If the transmission data is registered in the table, the transmission data is queued in the transmission queue (one of the queues Q1 to Qn) of the registered priority. On the other hand, when the MAC address is not registered in the MAC address-priority correspondence table, the classification processing unit 31 queues the transmission data in a default transmission queue (any one of the queues Q1 to Qn).
[0073]
As a method of determining the priority by analyzing the header information, a method of analyzing various information may be used. For example, a method of analyzing a port number of a transmission source, a method of analyzing a port number of a destination (transmission destination), or the like. The priority can be determined by a method of analyzing a port number or a method of analyzing a protocol type such as UDP or TCP.
Also, the terminal address is not limited to the MAC address, but may be, for example, an IP address or another address.
[0074]
As described above, the packet transfer device of the present example includes the transfer control unit 1, the reception unit 2, and the transmission unit 3, and the transmission control unit 1 transmits the packet received from the reception unit 2 from the transmission unit 3. The transfer control unit 1 has two or more different processing modes, and performs switching control of these processing modes.
[0075]
Further, in this example, the processing mode includes a first processing mode (processing mode 1 processing mode) in which the packets received from the receiving unit 2 are transmitted from the transmitting unit 3 in the order in which the packets are received. A second processing mode (processing mode 2) in which the transmitting unit 3 transmits the packets in the order in which the packets are received and rearranged in accordance with a predetermined rule from the received order.
[0076]
In this example, the switching control unit 13 receives a signal from the outside and performs switching control of the first processing mode and the second processing mode based on the signal.
Further, in this example, in the first processing mode, the transfer control of the packet is performed by the processing in the lower layer 11, and in the second processing mode, the transfer control of the packet is performed by the processing in the upper layer 12.
Further, in this example, when the mode is switched from the second processing mode to the first processing mode, the packet held in the upper layer 12 is transferred to the lower layer 11.
[0077]
Then, in the packet transfer device of this example, switching control of the form of packet transfer processing is adaptively performed according to the information transmission speed in the wireless section.
Specifically, in the packet transfer device of this example, when the information transmission rate in the wireless section on the transmission side is greater than a predetermined threshold, the first packet transfer is executed in the lower layer (lower layer) 11. When the information transmission rate in the wireless section on the transmitting side is smaller than a predetermined threshold value, the packet transfer is performed in the higher layer (upper layer) 12 in the second processing mode. Operate.
The upper layer 12 reads the header information and the like of the packet and executes queuing in consideration of the QoS such as the priority of the packet. In the lower layer 11, the packets received from the receiving unit 2 or the upper layer 12 are sequentially sent to the transmitting unit 22.
[0078]
Accordingly, when the information transmission rate on the transmission side is smaller than a predetermined threshold, a high-priority packet is transmitted preferentially from the transmission unit 3, and when the information transmission rate on the transmission side decreases. Can maintain the required network environment. On the other hand, when the information transmission rate on the transmitting side is higher than a predetermined threshold, the transfer processing is performed only in the lower layer 11, so that high-speed transfer processing is possible, and the transmission delay time of the packet is increased and the throughput is reduced. Drops can be avoided.
[0079]
Furthermore, when the information transmission speed in the wireless section is low, there is a margin for the processing time of the transfer control, and it is possible to execute the QoS control processing of the transmission data by the upper layer 12 using the extra processing time. Yes, this makes it unnecessary to provide a high-speed processor, for example, and provides high-quality services with inexpensive hardware.
[0080]
Therefore, in the packet transfer apparatus of the present example, the QoS control of the packet to be transferred adaptively is performed according to the information transmission speed on the transmission side, which is effective for improving the service quality. Further, when the information transmission speed on the transmitting side is higher than a predetermined threshold and the transmission rate is high, the transfer process is performed only in the lower layer 11, so that a high-speed transfer process can be realized. Further, when the information transmission rate on the transmission side is smaller than a predetermined threshold and the transmission rate is low, the extra transmission processing time is reduced by decreasing (slowing) the information transmission rate in the wireless section, and the QoS control is performed. By allocating to processing, for example, a high-speed processor is not required, and a power saving, small heat generation, small size, and inexpensive system can be realized.
[0081]
In the packet transfer device of the present example, a packet transfer unit is configured by the functions of the receiving unit 2, the transmission unit 3, the lower layer 11 and the upper layer 12, and the function of the switching control unit 13 is used to switch the packet transfer mode switching unit. It is configured.
Further, in the packet transfer device of the present example, a packet receiving unit is configured by the function of the receiving unit 2 and the receiving function of the transfer control unit 1, and the packet transmitting unit is configured by the function of the transmitting unit 3 and the transmitting function of the transfer control unit 1. Is configured.
[0082]
Further, in the packet transfer device of the present example, as a function of the first layer 11, a reception buffer unit is configured by the function of the reception buffer 21, and a transmission buffer unit is configured by the function of the transmission buffer 22. As a function of the second layer 12, packet classification means is constituted by the function of the classification processing section 31, and packet queue means is constituted by the functions of the plurality of queues Q1 to Qn. The function of the unit 33 constitutes a packet reading means.
[0083]
Further, in the packet transfer device of this example, a wireless communication unit is configured by the function of the wireless device 42 having the antenna 43.
Further, in the packet transfer device of this example, as a plurality of different transfer modes, a transfer mode in the first processing mode corresponding to the processing mode 1 and a transfer mode in the second processing mode corresponding to the processing mode 2 are described. Used.
Further, in the packet transfer device of this example, the reception buffer 21 having a region for storing one packet is used. However, for example, a device that stores a plurality of packets and performs processing in the order of reception is used. You may.
[0084]
Here, the configurations of the packet transfer device and the wireless communication system according to the present invention are not necessarily limited to those described above, and various configurations may be used. Note that the present invention can be provided, for example, as a method or a method for executing the processing according to the present invention, or a program for realizing such a method or method.
Further, the application field of the present invention is not necessarily limited to the above-described fields, and the present invention can be applied to various fields.
[0085]
The various processes performed in the packet transfer device, the wireless communication system, and the like according to the present invention include, for example, a control program stored in a ROM (Read Only Memory) by a processor in hardware resources including a processor and a memory. A configuration controlled by execution may be used. For example, each functional unit for executing the processing may be configured as an independent hardware circuit.
Further, the present invention can be understood as a computer-readable recording medium such as a floppy (registered trademark) disk or a CD (Compact Disc) -ROM storing the above-mentioned control program or the program (the program itself). The processing according to the present invention can be performed by inputting the program from the recording medium to the computer and causing the processor to execute the program.
[0086]
【The invention's effect】
As described above, the packet transfer device according to the present invention has a function of transferring a packet in a plurality of different transfer modes. Thus, the transfer mode for transferring the packet is switched, so that the efficiency of the packet transfer can be improved.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration example of a packet transfer device according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a configuration example of a wireless communication system according to an embodiment of the present invention.
FIG. 3 is a flowchart illustrating an example of a procedure of a reception process performed by a transfer control unit.
FIG. 4 is a flowchart illustrating an example of a procedure of a transmission process performed by a transfer control unit.
FIG. 5 is a flowchart illustrating an example of a procedure of processing at the time of processing mode switching performed by a transfer control unit.
FIG. 6 is a diagram illustrating an example of a process of determining a priority based on header information of transmission data.
FIG. 7 illustrates an example of a header format.
FIG. 8 is a diagram illustrating an example of a correspondence between a port number and a priority;
FIG. 9 is a diagram illustrating an example of a correspondence between a MAC address and a priority;
[Explanation of symbols]
1. transfer control unit, 2. reception unit, 3. transmission unit, 11. lower layer,
12. Upper layer, 13 Switching control unit, 21 Receive buffer,
22: transmission buffer, 31: classification processing unit, 32: queue unit,
33. · Packet reading section, Q1 to Qn ·· Queue,
41: Packet transfer device, 42: Radio, 43: Antenna,
51-Server, 52-Client, 53-Transmission line,

Claims (1)

In a packet transfer device for transferring a packet,
Packet transfer means having a function of transferring a packet by a plurality of different transfer modes;
Packet transfer mode switching means for switching a transfer mode for transferring a packet by the packet transfer means;
A packet transfer device comprising:

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