JP2007013510A - Packet communication system and packet communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a packet communication system adopting a packet switching system executing duplex communication capable of executing a service with high quality even on the occurrence of a delay or missing in a communication packet that can decide the identification of packets with a simple method. <P>SOLUTION: A transmitter side packet switching apparatus 110 respectively transmits communication packets each including the same user data, the same sequence number, and identification information denoting multiple communication to two systems of communication networks. A receiver side packet switching apparatus 120 decides whether or not the communication packets received from the two systems of the communication networks include the identification information, decides the identification of the communication packets on the basis of a sender address and the sequence number when the communication packets include the identification information, and aborts one of the communication packets when it is the same as the communication packet having been already received. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a packet communication system and a packet communication apparatus that perform multiplex communication of the same communication packet.

  Conventionally, a packet switching system is known as a kind of communication system. In a communication network that employs a packet switching method, an arbitrary line is used in units of communication packets, so that the line is not exclusively used by the transmission side and the reception side, and therefore the use efficiency of the communication line can be improved. .

  However, in a packet switching network, communication packets may be delayed or lost due to network congestion or the like, which may degrade service quality. For example, in an image communication service, a frame of a moving image (an image for one frame) may be lost due to packet loss, which may deteriorate image quality. In addition, in a communication service such as a transaction processing service that does not allow communication data to be lost, if a communication packet is lost, the communication packet must be retransmitted, resulting in a decrease in communication response.

  In addition, for example, when a communication line connecting the packet switching network and the communication device is disconnected, the communication packet may not reach the destination due to the occurrence of a communication failure. In such a case, the communication service itself cannot be provided. Conventionally, the communication line is made redundant and the path is automatically switched when a failure occurs, thereby speeding up the recovery from the communication failure. However, since such a method cannot prevent the occurrence of a communication failure itself, the communication service must be interrupted from the time of the occurrence of the failure until the failure recovery function is automatically activated. The

As a technique for preventing delay / loss of communication packets, for example, a technique described in Patent Document 1 below is known. In this technique, a copy of a communication packet is generated by an input packet switch of a packet switching network (see paragraph 0030 of the same patent document), and the original communication packet and the copy packet reach the destination via different communication paths. Header information (routing tag) is set in (see paragraphs 0034 to 0036 of the same document), thereby suppressing packet delay and loss. Further, the output packet switch of the packet switching network determines the identity of the copy packet based on the information content of the communication packet, and discards the copy packet having the same content (see paragraphs 0032 and 0036 of the patent document). .
Japanese Patent No. 3083133

  However, the technique of Patent Document 1 has a drawback that it cannot cope with a service interruption due to a communication failure such as disconnection in a communication line connecting a packet switching network and a communication device.

  In addition, since the routing tag must be individually set so that the original communication packet and the copy packet reach the destination via different paths, there is a disadvantage that the work load for route determination is large.

  Furthermore, in the technique of Patent Document 1, since a copy of all input communication packets is generated, multiplex transmission is performed even for a service in which delay / loss of communication packets does not pose a major problem. For this reason, the technique disclosed in Patent Document 1 has a drawback that the congestion of the packet switching network is unnecessarily increased.

  Moreover, in the technique of Patent Document 1, since the identity of the copy packet is determined based on the information content of the communication packet, the processing load for such identity determination increases, and the output packet switch is expensive. There is also a drawback of becoming.

  An object of the present invention is to provide a packet communication system and a packet communication apparatus that can provide a high-quality service even when a communication packet is delayed or lost or a communication failure occurs at low cost.

  (1) The first invention relates to a packet communication system in which a transmission device and a reception device are connected via a plurality of communication networks.

  The transmitting apparatus includes means for transmitting communication packets storing the same user data, the same sequence number, and identification information indicating multiplex communication to a plurality of communication networks, respectively, and receiving A communication packet using a means for determining whether or not identification information is stored in a communication packet received from a communication network of a plurality of systems, and a transmission source address and a sequence number when the identification information is stored. And a means for discarding a communication packet determined to be the same as a communication packet that has already been received.

  (2) The packet communication apparatus according to the second invention transmits communication packets storing the same user data, the same sequence number, and identification information indicating multiplex communication to a plurality of communication networks, respectively. A transmission unit having means for determining whether or not identification information is stored in a communication packet received from a plurality of communication networks, a transmission source address and a sequence number when the identification information is stored And a receiving unit having means for determining the identity of the communication packet using and a means for discarding the communication packet determined to be the same as the already received communication packet.

  According to the first and second inventions, since the transmission side device and the reception side device are connected via a plurality of communication networks, service interruption due to disconnection of the communication line is unlikely to occur, and communication There is no need to set the route individually.

  In addition, since it is possible to determine whether or not to perform multiplex communication on the transmission side, it is possible to perform multiplex transmission only for services where delay / loss of communication packets is a major problem, and wastefully increases communication network congestion. I will not let you.

  In addition, since the identity of the communication packet is determined using the source address and the sequence number, it is easy to determine the identity.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the size, shape, and arrangement relationship of each component are shown only schematically to the extent that the present invention can be understood, and the numerical conditions described below are merely examples. .

First Embodiment A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a conceptual diagram schematically showing the overall configuration of the packet communication system according to this embodiment. As shown in FIG. 1, the packet communication system 100 of this embodiment includes two packet switching devices 110 and 120 and two systems of packet switching networks 130 and 140.

  Each of the packet switching apparatuses 110 and 120 implements a unique function and service, and requests the other packet switching apparatus to provide the function and service. The internal structure of the packet switching devices 110 and 120 will be described later with reference to FIG.

  The packet switching network 130 is connected to the packet switching device 110 via the interface IF11 and is connected to the packet communication 120 via the interface IF21. Similarly, the packet switching network 140 is connected to the packet switching device 110 via the interface IF 12 and is connected to the packet communication 120 via the interface IF 22. Two identical communication packets transmitted from one of the packet switching devices 110 and 120 are transferred through the packet switching networks 130 and 140 and reach the other packet switching device except when a packet loss or communication failure occurs. To do. In this embodiment, these packet switching networks 130 and 140 are constructed as separate and independent communication networks that do not have shared resources. Therefore, even if communication failure or congestion occurs in one of the packet switching networks 130 and 140, the other packet switching network is not affected.

  In FIG. 1, two packet switching apparatuses are connected via two packet switching networks. However, these packet switching apparatuses 110 and 120 may be connected by three or more packet switching networks. Furthermore, three or more packet switching devices may be interconnected by two or more packet switching networks.

  FIG. 2 is a block diagram schematically showing the internal configuration of the packet switching apparatus 110 according to this embodiment. The internal configuration of the packet switching device 120 may be the same as this.

  As shown in FIG. 2, the packet switching apparatus 110 of this embodiment includes an application function unit 210, a packet transmission / reception function unit 220, and packet input / output units 230 and 240.

  The application function unit 210 implements functions and services unique to the packet switching apparatus 110. The application function unit 210 receives data received from other packet switching devices via the packet transmission / reception function unit 220. Further, the application function unit 210 passes data to be transmitted to other packet switching devices, a destination address, and the like to the packet transmission / reception function unit 220.

  The packet transmission / reception function unit 220 generates a communication packet using the data and the destination address received from the application function unit 210. The packet transmission / reception function unit 220 has a function of transmitting the same communication packet one by one (hereinafter referred to as “single transmission”) and a function of transmitting two each (hereinafter referred to as “double transmission”). As will be described later, when duplex transmission is performed, the packet transmission / reception function unit 220 stores identification information indicating a duplex communication and a sequence number in a communication packet, and packet input / output units 230 and 240. Pass to both. Further, the packet transmission / reception function unit 220 receives the packets received by the packet input / output units 230 and 240. As will be described later, when receiving two identical communication packets, the packet transmission / reception function unit 220 discards one of them. Further, the packet transmission / reception function unit 220 includes a hold buffer 221 and a hold timer 222. The hold buffer 221 can temporarily store one communication packet for each transmission source address of the received communication packet, and is used for rearrangement when the reception order of communication packets is reversed. The hold timer 222 is used for managing the hold time of the hold buffer 221. In the packet communication system 100 according to this embodiment, since one packet switching apparatus is connected to two packet switching networks 130 and 140, there may be cases where two types of address values are provided. In such a case, it can be considered that the addresses are substantially the same, and therefore, in the present application, the description will be made as “the same address”.

  The packet input / output unit 230 transmits the communication packet received from the packet transmission / reception function unit 220 to one packet switching network 130, and passes the communication packet received from the packet switching network 130 to the packet transmission / reception function unit 220. Similarly, the packet input / output unit 240 transmits the communication packet received from the packet transmission / reception function unit 220 to the other packet switching network 140, and receives the communication packet received from the packet switching network 140 to the packet transmission / reception function unit 220. hand over.

  FIG. 3 is a conceptual diagram showing a layer structure adopted in the packet communication system 100.

  As shown in FIG. 3, the layer structures of the packet switching apparatuses 110 and 120 are, from the lower layer side, Ethernet (registered trademark) layer Eth (primary Eth (P) and secondary Eth (S)), IP layer, two layers, respectively. It has a heavy communication control layer, a TCP / UDP layer, and an application layer.

  The Ethernet (registered trademark) layer corresponds to a physical layer and a data link layer of an OSI (Open Systems Interconnection) reference model, and is a layer for performing network connection between the packet switching apparatuses 110 and 120. Of the Ethernet (registered trademark) layer Eth of the packet switching apparatus 110, the primary Eth (P) corresponds to the interface IF11, and the secondary Eth (s) corresponds to the interface IF12 (see FIG. 1). In the Ethernet (registered trademark) layer Eth of the packet switching apparatus 120, the primary Eth (P) corresponds to the interface IF21, and the secondary Eth (S) corresponds to the interface IF22.

  The IP layer corresponds to the lower layer of the network layer in the OSI reference model, and executes IP (Internet protocol) control.

  The duplex communication control layer is a layer responsible for controlling duplex communication according to this embodiment. That is, the duplex communication control layer adds identification information and a sequence number to a transmission packet, and performs double reception control by reading the identification information and sequence number from the received packet (described later). In this embodiment, the dual communication control layer is provided as an upper layer of the network layer in the OSI reference model.

  The TCP / UDP layer corresponds to the transport layer of the OSI reference model, and executes normal TCP (Transmission Control Protocol) and UDP (User Datagram Protocol).

  The application layer corresponds to the session layer, presentation layer, and application layer of the OSI reference model, and executes Telnet, DNS (Domain Name Service), HTTP (Hyper Text Transfer Protocol), FTP (File Transfer Protocol), and the like.

  Thus, in this embodiment, since the dual communication control layer is provided between the TCP / UDP layer and the IP layer, the dual communication control can be performed without affecting the control of the TCP / UDP and the application layer. It can be carried out. In addition to this embodiment, the present invention can be realized by performing dual communication control at the socket level (port number).

  Hereinafter, the operation of the packet communication system 100 according to this embodiment will be described.

  First, the transmission operation of the packet switching apparatus (here, the packet switching apparatus 110) will be described.

  When the packet switching apparatus 110 transmits a communication packet, first, a transmission request is sent from the application function unit 210 to the packet transmission / reception function unit 220. This transmission request includes transmission data (user data) and a destination address. When receiving the transmission request, the packet transmission / reception function unit 220 determines whether the transmission is single transmission / duplex transmission. This determination can be made, for example, by registering in advance in the packet transmission / reception function unit 220 a destination address for performing double transmission.

  When performing single transmission, the packet transmission / reception function unit 220 uses the transmission data and the destination address received from the application function unit 210 to generate a communication packet in the same manner as in the past. In the case of single transmission, the above identification information and sequence number are not stored in the communication packet. The generated communication packet is sent to one of the packet input / output units 230 and 240. The packet input / output unit (230 or 240) that has received the communication packet transmits the communication packet to the corresponding packet switching network (130 or 140).

  When performing dual transmission, the packet transmission / reception function unit 220 generates a communication packet by using identification information and a sequence number in addition to transmission data and a destination address received from the application function unit 210. The form of the identification information is arbitrary, and it is sufficient that the receiving side packet switching apparatus can recognize that it is duplex transmission. The sequence number is a number indicating the transmission order of communication packets transmitted to the same destination address. The initial value of the sequence number is arbitrary, but is incremented by “+1” each time a communication packet is generated. The packet transmission / reception function unit 220 temporarily stores a sequence number for each registered destination address (destination address for dual transmission). The storage position of the identification information and sequence number may be determined in correspondence with the layer structure shown in FIG. 3, for example. Further, as this sequence number, a sequence number used in TCP (Transmission Control Protocol) or RTP (Real-time Transport Protocol) may be used. The generated communication packet is sent to both the packet input / output units 230 and 240. The packet input / output units 230 and 240 that have received the communication packet transmit the communication packet to the corresponding packet switching networks 130 and 140, respectively. Therefore, the same sequence number is stored in a pair of communication packets related to one double transmission.

  Next, the reception operation of the packet switching apparatus will be described.

  The packet input / output units 230 and 240 receive communication packets from the corresponding packet switching networks 130 and 140 as needed. The received communication packet is sent to the packet transmission / reception function unit 220.

  4 and 5 are flowcharts for explaining the reception operation of the packet transmission / reception function unit 220. FIG.

  When receiving a communication packet from the packet input / output units 230 and 240, the packet transmission / reception function unit 220 first checks whether or not identification information is stored in the communication packet (see step S401 in FIG. 4). If the identification information is not stored, the packet transmission / reception function unit 220 determines that the communication packet is a communication packet for single transmission, and notifies the application function unit 210 of reception of the communication packet (step S402). And the processing related to the received packet is terminated.

  On the other hand, when the identification information is stored in step S401, the packet transmission / reception function unit 220 determines that the communication packet is a communication packet related to double transmission, and sets the sequence number of the received packet as an expected value. Compare (see step S403). The packet transmission / reception function unit 220 stores the addresses of other packet switching devices that can perform double transmission, and for each address, the sequence number (expected value) of the communication packet to be received next Is temporarily saved. When the packet switching apparatus 110 is powered on, the expected value corresponding to each address is set to an initial value. When the sequence number of the received packet matches the expected value, the packet transmission / reception function unit 220 increments the expected value by “+1” (see step S404) and notifies the application function unit 210 of reception of the communication packet. (See step S405).

  Subsequently, the packet transmission / reception function unit 220 checks the hold buffer 221 (see step S406). When the communication packet is not stored in the hold buffer 221, the packet transmission / reception function unit 220 ends the process related to the received packet. On the other hand, when it is determined in step S406 that the communication packet is stored in the hold buffer 221, the packet transmission / reception function unit 220 compares the sequence number of the hold packet with the sequence number of the received packet (see step S407). .

  When these sequence numbers are consecutive, the packet transmission / reception function unit 220 notifies the application function unit 210 of the communication packet (hold packet) stored in the hold buffer 221 (see step S408), and the expected value of the sequence number. Is further incremented by “+1” (see step S409), the hold timer 222 is stopped and the hold buffer 221 is released (see steps S410 and S411), and the process for the received packet is terminated. By such processing, when two consecutive packets are received in the reverse order, the order can be corrected and transferred to the application function unit 210.

  On the other hand, if the sequence numbers are not consecutive in step S407, the hold timer 222 is restarted and the processing related to the received packet is terminated. By this process, the holding time of the holding buffer 221 is extended.

  If the sequence number does not match the expected value in step S403, the packet transmission / reception function unit 220 checks whether or not the received communication packet is the same as the already received communication packet (see step S501 in FIG. 5). . For example, when the sequence number is greater than or equal to the initial value and smaller than the expected value stored therein, the communication packet is the same as the already received communication packet (ie, each packet switched network 130, 140 is It is possible to determine that both of the same communication packets transmitted through the network have been normally received. If it is determined that they are the same, the packet transmission / reception function unit 220 discards the communication packet (see step S502), and ends the process for the received packet.

  When it is determined in step S501 that the communication packet is not the same as the received communication packet, the packet transmission / reception function unit 220 determines whether the communication packet is stored in the hold buffer 221 (see step S503). If the hold buffer 221 is empty, the received packet is stored (see step S504), the hold timer 222 is started (see step S505), and the process related to the received packet is ended. When the time measured by the hold timer 222 reaches a predetermined hold time, the communication packet in the hold buffer 221 is discarded. Normally, the timing of the hold timer 222 reaches a predetermined hold time when one or more communication packets are lost in both the packet switching networks 130 and 140. In such a case, the hold buffer 221 is used. This is because it is considered that it is not useful to deliver only one of the communication packets to the application function unit 210. When a communication packet is lost, for example, in TCP or the like, a request for retransmission of the communication packet is transmitted to the counterpart packet switching apparatus by an instruction of the application function unit 210. The holding time is arbitrary, but is set to, for example, several milliseconds to several tens of milliseconds.

  If it is determined in step S503 that the communication packet is stored in the hold buffer 221, the packet transmission / reception function unit 220 compares the sequence number of the stored packet with the sequence number of the received packet (see step S506).

  When these sequence numbers are consecutive, the packet transmission / reception function unit 220 determines that these communication packets have been received in reverse order, and delivers the received packet and the hold packet to the application function unit 210 (see step S507). The hold timer 222 is stopped (see step S508), the hold packet is released by releasing the hold buffer (see step S509), and the expected value of the sequence number is incremented by “+1” (see step S510). ), The processing related to the received packet is terminated.

  If the sequence numbers match in step S506, the packet transmission / reception function unit 220 determines that these communication packets are the same packet, and sends the received packet to the application function unit 210 (see step S511). When a received packet having a sequence number larger than the expected value is stored in the hold buffer 221 and the same communication packet as the stored packet is received due to the reverse of the receiving order or loss of the previous communication packet, the same in step S506 A determination is made that this is a packet. The packet transmission / reception function unit 220 stops the hold timer 222, releases the hold buffer, and increments the expected value (see steps S508 to S510), and ends the process related to the received packet.

  On the other hand, if the sequence numbers do not match and are not consecutive in step S506, the packet transmission / reception function unit 220 overwrites the received packet in the hold buffer 221 (see step S512) and restarts the hold timer 222 ( In step S513, the process related to the received packet is terminated. In step S506, the sequence numbers become discontinuous in many cases when communication packets are lost in both the packet switching networks 130 and 140. In such a case, only one communication packet in the hold buffer 221 is applied to the application function. This is because it is considered that it is not useful to hand over to the section 210.

  As described above, according to this embodiment, whether or not to perform duplex communication can be determined by the transmission side packet switching devices 110 and 120, so that the delay / loss of communication packets is a serious problem. Multiplex transmission can be performed only on the network, and congestion of the packet switching networks 130 and 140 is not increased unnecessarily.

  In addition, in the packet switching devices 110 and 120 of this embodiment, the identity of the communication packet is determined using the source address and the sequence number, and this determination process is performed between the TCP / UDP layer and the IP layer. Therefore, the identity determination process is simple and does not affect the control of the upper layer (TCP / UDP or application layer).

  Furthermore, since the packet switching apparatus on the transmission side and the packet switching apparatus on the reception side are connected via the two systems of packet switching networks 130 and 140, service interruption due to disconnection of the communication line is unlikely to occur. Need not be set individually.

  In this embodiment, the sequence number of the communication packet is assigned to each destination address in the transmission side packet switching apparatus and is checked for each transmission source address in the reception side packet switching apparatus. (That is, a series of sequence numbers are assigned to a plurality of communication packets having the same address and the same application session). This makes it possible to manage double transmission for each application session.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS.

  The configurations of the packet communication system and the packet switching apparatus according to this embodiment are substantially the same as those in the case of the first embodiment (see FIGS. 1 to 3). However, the hold buffer provided in the packet transmission / reception function unit in the packet switching device can temporarily store a plurality of communication packets for each source address and a hold timer is provided for each of the plurality of hold packets. Different from the first embodiment.

  Further, the transmission operation of the packet switching apparatus is the same as that of the first embodiment.

  6 and 7 are flowcharts for explaining the reception operation of the packet transmission / reception function unit according to this embodiment.

  When receiving a communication packet from each packet input / output unit (see FIG. 2), the packet transmission / reception function unit first checks whether the identification information is stored in the communication packet (see step S601 in FIG. 6). When the identification information is not stored, the packet transmission / reception function unit determines that the communication packet is a communication packet related to single transmission, and notifies the application function unit of reception of the communication packet (see step S602). Then, the process related to the received packet is terminated.

  On the other hand, when the identification information is stored in step S601, the packet transmission / reception function unit determines that the communication packet is a communication packet related to double transmission, and compares the sequence number with the expected value (step S603). reference). When the sequence number of the received packet matches the expected value, the packet transmission / reception function unit increments the expected value by “+1” (see step S604), and notifies the application function unit of reception of the communication packet (step S604). (See S605).

  Subsequently, the packet transmission / reception function unit checks the hold buffer (see step S606). When the communication packet is not stored in the hold buffer, the packet transmission / reception function unit ends the process related to the received packet. On the other hand, if it is determined in step S606 that one or more communication packets are stored in the hold buffer, the packet transmission / reception function unit compares the sequence numbers of each hold packet and the received packet with each other (see step S607). . Then, for the communication packets having the consecutive sequence numbers, reception notification to the application function unit is performed (see step S608), and the expected value of the sequence number is incremented by the number of notified communication packets (see step S609). For example, if the sequence numbers of two pending packets are “n + 2” and “n” and the sequence number of the received packet is “n + 1”, the sequence numbers of these three communication packets are consecutive. The reception of the communication packet is notified to the application function unit. On the other hand, when the sequence numbers of the two pending packets are “n + 2” and “n” and the sequence number of the received packet is “n−1”, the pending packet and the received packet with the sequence number “n” are application functions. Is notified.

  Subsequently, the packet transmission / reception function unit checks whether or not a pending packet remains in the pending buffer (step S610). If no pending packet remains, the pending timer is stopped (see step S611) and the pending buffer is released (see step S612), and the processing related to the received packet is terminated.

  On the other hand, if there are no pending / received packets with consecutive sequence numbers in step S607, or if there are any pending packets remaining in the pending buffer in step S610, the pending timer is restarted to process the received packet. Exit.

  If the sequence number does not match the expected value in step S603, the packet transmission / reception function unit checks whether the received communication packet is the same as the already received communication packet, as in the first embodiment ( (See step S701 in FIG. 7). If it is determined that they are the same, the packet transmission / reception function unit discards the communication packet (see step S702), and ends the process related to the received packet.

  On the other hand, if it is determined in step S701 that it is not the same as the communication packet that has already been received, the packet transmission / reception function unit determines whether there is a vacant buffer (see step S703). If there is a vacancy in the hold buffer, the received packet is stored in one of the vacant portions (see step S704), the hold timer is started (see step S705), and the process related to the received packet is terminated. .

  If it is determined in step S703 that there is no space in the holding buffer, the packet transmission / reception function unit notifies the reception of the one with the largest sequence number in the stored packet (see step S706), and also sends the expected value of the sequence number to the sequence. A value that is larger by “+1” than the number is set (see step S707), all the hold buffers are released (see step S708), the hold timer is stopped (see step S709), and the process for the received packet is performed. finish. Communication packets are temporarily stored in all the hold buffers in many cases when communication packets are lost in both packet-switched networks. In such a case, only a few communication packets in the hold buffer are applied to the application. This is because it is considered that it is not useful to deliver it to the functional part.

  As described above, according to this embodiment, for the same reason as in the first embodiment described above, congestion of the packet switching network is not increased unnecessarily, and the identity determination process is simple and can be performed at other layers. The service control is not affected, the service interruption due to the disconnection of the communication line is difficult to occur, and it is not necessary to set the communication path individually.

  In addition, according to this embodiment, since a plurality of communication packets can be temporarily stored in the hold buffer at the same time, the number of communication packets to be relieved can be increased.

  The point that communication packets may be managed for each application session is the same as in the first embodiment.

It is a conceptual diagram which shows the whole structure of the packet communication system which concerns on 1st Embodiment. It is a block diagram which shows the internal structure of the packet switching apparatus which concerns on 1st Embodiment. It is a conceptual diagram which shows the layer structure of the packet communication system which concerns on 1st Embodiment. It is a flowchart for demonstrating operation | movement of the packet switching apparatus which concerns on 1st Embodiment. It is a flowchart for demonstrating operation | movement of the packet switching apparatus which concerns on 1st Embodiment. It is a flowchart for demonstrating operation | movement of the packet switching apparatus which concerns on 2nd Embodiment. It is a flowchart for demonstrating operation | movement of the packet switching apparatus which concerns on 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Packet communication system 110,120 Packet switching apparatus 130,140 Packet switching network 210 Application function part 220 Packet transmission / reception function part 230,240 Packet input / output part

Claims (9)

A packet communication system in which a transmission device and a reception device are connected via a plurality of communication networks,
The transmission device includes means for transmitting communication packets each storing the same user data, the same sequence number, and identification information indicating multiplex communication to the communication networks of the plurality of systems; and
Means for determining whether or not the identification information is stored in the communication packet received from the plurality of communication networks; a transmission source address and the sequence when the identification information is stored; Means for determining the identity of the communication packet using a number, and means for discarding the communication packet determined to be the same as the communication packet already received.
A packet communication system. The transmitting device issues the sequence number for each session of an application corresponding to the communication packet; and
The receiving apparatus determines that the communication packet and the communication packet that has already been received are the same only when the source address, the sequence number, and the session of the application all match.
The packet communication system according to claim 1.   3. The packet communication system according to claim 1, wherein the determination of the identity of the communication packet is executed as a process related to a layer between an original network layer and a transport layer.   3. The packet communication system according to claim 1, wherein a sequence number defined by a transmission control protocol or a real-time transport protocol is used as the sequence number.   The packet communication system according to claim 1, wherein the plurality of communication networks are separate and independent communication networks that do not have a shared resource. A transmission unit having means for transmitting communication packets each storing the same user data, the same sequence number, and identification information indicating multiplex communication to a plurality of communication networks;
Using the means for determining whether or not the identification information is stored in the communication packet received from the communication network of the plurality of systems, and using the transmission source address and the sequence number when the identification information is stored A receiving unit comprising: means for determining the identity of the communication packet; and means for discarding the communication packet determined to be the same as the communication packet that has already been received.
A packet communication device comprising: The transmitter issues the sequence number for each session of an application corresponding to the communication packet; and
The receiving unit determines that the communication packet and the communication packet that has already been received are the same only when the source address, the sequence number, and the session of the application all match.
The packet communication apparatus according to claim 6.   8. The packet communication apparatus according to claim 6, wherein the determination of the identity of the communication packet is executed as a process related to a layer between an original network layer and a transport layer.   The packet communication device according to claim 6 or 7, wherein a sequence number defined by a transmission control protocol or a real-time transport protocol is used as the sequence number.