Packet transfer device, packet transfer method, and packet transfer system

Abstract

To continue communication that maintains reliability.SOLUTION: A packet transfer device for transferring a packet via a plurality of independent communication paths provided between facing packet transfer devices includes an addition part for adding an identifier that can determine a packet having a packet order and the same information to the packet, a destination determination part for determining a packet destination, a reproduction part for reproducing the packet with the identifier added thereto, a redundant packet transmission part respectively transmitting the reproduced packet to the plurality of communication paths, and an overlapping determination part for determining the packet having the same information with reference to the identifier. The destination determination part determines whether to have route information to a destination of a reception packet. A user packet transmission part transfers a packet determined to have the route information to the destination to a specific network device, and the redundant packet transmission part transfers a packet determined to have no route information to the destination to all communicable packet transfer devices.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a packet forwarding device. [Background technology]

[0002] When communicating wirelessly with a mobile station, radio waves may be blocked by buildings or other mobile stations, resulting in interruptions even within the wireless communication area. One way to compensate for this is to transmit one or more duplicated packets containing the same information over multiple independent communication paths. A packet forwarding device with this functionality uses two methods: transmitting multiple packets containing the same information over a single communication path, and transmitting multiple packets containing the same information over multiple communication paths. This method allows communication to continue even when a communication path fails or the packet loss rate is high.

[0003] Furthermore, as a method for a mobile station that cannot communicate with a base station to continue communication, a method has been proposed in which the mobile station relays packets using inter-device communication between mobile stations (Patent Document 1).

[0004] Patent document 1 (JP 2009-302688 A) describes a mobile terminal that includes a mobile phone function unit that checks the connection status with a mobile base station and, if connected, exchanges information with the mobile base station; a storage unit that stores information received and generated by the mobile phone function unit; a communication control unit that obtains connection information indicating the connection status with the mobile base station from the mobile phone function unit and, if not connected, generates a control signal; and a storage-type multi-hop communication function unit that starts up in response to the control signal, establishes a session with a first mobile terminal after startup, stores the information received from the first mobile terminal and the generated information in the storage unit, and, if a session with a second mobile terminal is established, transmits the information stored in the storage unit and stores the information received from the second mobile terminal in the storage unit.

[0005] Furthermore, Patent Document 2 (JP 2023-145059 A) describes a packet forwarding device that forwards packets, and has multiple independent communication paths between it and an opposing packet forwarding device, and the packet forwarding device is equipped with an addition unit that adds an identifier that can determine the order of packets and packets that have the same information, a duplication unit that duplicates packets with the identifier added, a packet sending unit that sends the duplicated packets to each of the multiple communication paths, and a duplication determination unit that determines packets that have the same information by referring to the identifier, and the duplication unit controls the number of packets sent between the opposing packet forwarding device based on the communication environment between them. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-302688 [Patent Document 2] Japanese Patent Application Publication No. 2023-145059 Summary of the Invention [Problem to be solved by the invention]

[0007] In the background art described above, communication can continue as long as any one of multiple communication paths is normal. For example, in the technology described in Patent Document 1, a mobile station that can communicate with a base station receives a packet and transmits the packet to an inter-device communication network, thereby transferring the packet to a mobile station that cannot communicate with the base station.

[0008] However, even when multiple wireless communication areas are overlapped, radio waves may be blocked by moving objects within the area, causing all wireless communication to be interrupted. Also, in Patent Document 1, a packet relay function is activated when a connection with a base station is disconnected, causing a temporary interruption of communication.

[0009] Furthermore, the packet forwarding device described in Patent Document 2 forwards duplicated packets, which places a load on the network.

[0010] An object of the present invention is to provide a technology that enables reliable communication to be continued without causing communication interruptions even when a mobile station cannot communicate with a radio base station, thereby reducing the load on the network. [Means for solving the problem]

[0011] A representative example of the invention disclosed in the present application is as follows: That is, a packet forwarding device that forwards packets via a plurality of independent communication paths provided between opposing packet forwarding devices includes a user packet receiving unit that receives packets from other network devices, a user packet transmitting unit that transmits packets to the other network devices, an adding unit that adds an identifier to the packets that enables determination of the packet order and packets having identical information, a destination determining unit that determines the destination of the packets, a duplicating unit that copies the packets with the identifier added, a redundant packet transmitting unit that transmits the copied packets to each of the plurality of communication paths, and a duplication determining unit that refers to the identifier to determine packets having identical information, wherein the destination determining unit determines whether the received packet has route information to the destination, the user packet transmitting unit forwards a packet that has been determined to have route information to the destination to a specific network device, and the redundant packet transmitting unit forwards a packet that has been determined not to have route information to the destination to all packet forwarding devices that can communicate.

[0012] Furthermore, one example of a packet forwarding device of the present invention comprises a surviving hop count changing unit that changes the surviving hop count, and a surviving hop count determination unit that refers to the surviving hop count and determines whether to discard a received packet, wherein the adding unit adds to the packet the order of the packets, an identifier that can identify packets having identical information, and the surviving hop count, and the surviving hop count, and the surviving hop count changing unit changes the surviving hop count of a packet to be forwarded to another packet forwarding device.

[0013] Moreover, a packet forwarding device according to an embodiment of the present invention is characterized by comprising a device information storage unit that stores information about packet forwarding devices within the system.

[0014] In addition, in a packet forwarding device according to an embodiment of the present invention, the replicating unit refers to the device information storage unit and sets the destination of the packet forwarding device in the replicated packet.

[0015] In addition, a packet forwarding device according to an example of the present invention is characterized in that the device information storage unit stores the destination of a user network connected to the packet forwarding device, the adding unit adds a destination device ID to an identifier by referring to the destination of the received packet and the device information storage unit in addition to packet order and identity information, the copying unit sets the destination of the packet forwarding device in the copied packet by referring to the device information storage unit, the destination determination unit determines whether the destination device ID of the received packet is its own device ID, and the user packet sending unit forwards a packet for which the destination device ID of the received packet is determined to be its own device ID to a specific network device. [Effects of the Invention]

[0016] According to one aspect of the present invention, even if communication with a base station is not possible, the reliability of communication can be ensured by transferring packets between devices. Problems, configurations, and effects other than those described above will become clear from the description of the following embodiments. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a configuration diagram of a packet forwarding system according to a first embodiment of the present invention. [Figure 2] 1 is a diagram illustrating a configuration of a packet forwarding device according to a first embodiment. [Figure 3] FIG. 10 is a diagram illustrating the configuration of a packet to which a unique header is added according to the first embodiment. [Figure 4] 10 is a flowchart of a process for adding a unique header according to the first embodiment. [Figure 5] 10 is a flowchart of a process executed by a destination determination unit according to the first embodiment. [Figure 6] 10 is a flowchart of a process executed by a duplicate packet determining unit according to the first embodiment. [Figure 7] FIG. 10 is a diagram illustrating a configuration of a packet forwarding device according to a second embodiment of the present invention. [Figure 8] FIG. 10 is a diagram illustrating the configuration of a packet to which a unique header is added according to the second embodiment. [Figure 9] 10 is a flowchart of a process executed by a destination determination unit according to the second embodiment. [Figure 10] 10 is a flowchart of a process executed by a survival hop count determination unit according to the second embodiment. [Figure 11] FIG. 10 is a diagram illustrating a configuration of a packet forwarding device according to a third embodiment of the present invention. [Figure 12] FIG. 11 is a diagram illustrating information stored in a device information storage unit according to the third embodiment. [Figure 13] FIG. 10 is a diagram illustrating a configuration of a packet forwarding device according to a fourth embodiment of the present invention. [Figure 14] FIG. 10 is a diagram illustrating the configuration of a packet forwarding device according to a fifth embodiment of the present invention. [Figure 15] FIG. 13 is a diagram showing information stored in a device information storage unit according to the fifth embodiment. [Figure 16] FIG. 13 is a diagram illustrating the configuration of a packet to which a unique header is added according to the fifth embodiment. [Figure 17] 13 is a flowchart of a process executed by a destination determination unit according to the fifth embodiment. [Figure 18] FIG. 10 is a diagram illustrating the configuration of a packet forwarding device according to a sixth embodiment of the present invention. [Figure 19] FIG. 20 is a diagram showing the configuration of a packet to which a unique header is added in the sixth embodiment. [Figure 20] 19 is a flowchart of a process executed by a destination determination unit according to the sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Example 1 FIG. 1 is a configuration diagram of a packet forwarding system according to a first embodiment of the present invention.

[0019] The packet forwarding system of the first embodiment of the present invention includes opposing user networks 901, 902, and 911, packet forwarding devices 100 and 101 on the user network 900 side including the user networks 901 and 902, a packet forwarding device 200 on the user network 911 side, and an IP network 800 connecting the packet forwarding devices 100 and 101 with the packet forwarding device 200. The IP network 800 includes a plurality of independent communication paths 801 and 802 using different communication methods, and a communication path 811 for device-to-device communication. The user networks 901, 902, and 911 each include one or more network devices 301, 302, and 311. The network devices are, for example, general network switches that forward packets. The communication paths 801, 802, and 811 are configured with a plurality of packet forwarding devices or network devices, and may be configured as a wireless network, a wired network, or wireless networks of different methods.

[0020] Each of the user networks 901, 902, and 911 is a network made up of a plurality of network devices, and a plurality of terminals are connected to each of the user networks 901, 902, and 911. The terminals of the user networks 901 and 902 communicate with the terminal of the user network 911 via the IP network 800.

[0021] The packet forwarding devices 100 and 101 copy packets received from the user networks 901 and 902 and forward the packets to the respective communication paths 801, 802, and 811. Similarly, the packet forwarding device 200 copies packets received from the user network 911 and forwards the packets to the respective communication paths 801 and 802.

[0022] Communications between the packet forwarding devices 100, 101, 200 and the user network 900, and communications between the packet forwarding devices 100, 101, 200 and the IP network 800 may be wired or wireless as long as the communications method complies with the IP protocol. Furthermore, the packet forwarding devices 100, 101, 200 may be fixedly installed devices or portable devices. For example, the IP network 800 may be a wireless communication network, with a base station connected to the user network 911, and terminals that communicate with the base station connected to the user networks 901, 902.

[0023] There may be multiple packet forwarding devices on the user network 900 side and multiple packet forwarding devices on the user network 911 side. When there are multiple packet forwarding devices on the user network 900 side, there may be a communication path for inter-device communication, such as the communication path 811. When there are multiple packet forwarding devices on the user network 911 side, there may be a communication path for inter-device communication, such as the communication path 811.

[0024] 2 is a diagram showing the configuration of the packet forwarding device 100 according to the first embodiment of the present invention. The configuration of the packet forwarding device 100 is the same as that of the packet forwarding devices 101 and 200.

[0025] The packet forwarding device 100 includes a plurality of packet forwarding units 110 and 120 .

[0026] The packet forwarding unit 110 forwards packets from the user network 900 to the IP network 800, and includes a receiving unit 111, a unique header adding unit 112, a packet replicating unit 113, and multiple transmitting units 114a, 114b, and 114c. The receiving unit 111 receives packets input from the user network 900. The unique header adding unit 112 adds a unique header to the packets input from the user network 900. An example of the unique header will be described with reference to FIG. 3. The packet replicating unit 113 replicates the packets with the unique header added to generate redundant packets. The multiple transmitting units 114a, 114b, and 114c are provided corresponding to the communication paths 801, 802, and 811 of the IP network 800, and transmit the generated redundant packets to the communication paths 801, 802, and 811.

[0027] The packet forwarding unit 120 forwards packets from the IP network 800 to the user network 900, and includes a transmitting unit 121, a unique header removing unit 122, a duplicate packet determining unit 123, multiple receiving units 124a, 124b, and 124c, a packet reception history storing unit 125, and a destination determining unit 126. The multiple receiving units 124a, 124b, and 124c are provided corresponding to the communication paths 801, 802, and 811 of the IP network 800, and receive packets input from the IP network 800. The destination determining unit 126 determines the destination of the packet input from the IP network 800. The duplicate packet determining unit 123 determines packets having identical information input from the IP network 800. The unique header removing unit 122 removes the unique header from the packet input from the IP network 800. The transmitting unit 121 transmits the packet to a network device of the user network 900. The packet reception history storage unit 125 stores the packet reception history that is the determination result by the duplicate packet determination unit 123 .

[0028] In the IP network 800 according to the first embodiment of the present invention, packets are transferred using the UDP protocol, but other protocols may also be used.

[0029] FIG. 3 is a diagram showing the structure of a packet to which a unique header is added and which is transmitted to the IP network 800 according to the first embodiment of the present invention.

[0030] A UDP header is added to the beginning of the packet, followed by a UDP data area (payload). A proprietary header is placed between the UDP header and the UDP data area. It is recommended that the proprietary header use part of the beginning of the UDP data area.

[0031] The UDP header includes a source port number, a destination port number, a packet length, and a checksum.

[0032] The unique header includes packet identifier 1 and packet identifier 2. Packet identifier 1 includes time information in seconds and time information in milliseconds, and is composed of, for example, 32 bits. The time information is preferably represented in Unix Time, but may be represented in other formats (Unix is ​​a registered trademark, the same applies below). Packet identifier 2 includes a fixed value and a sequentially determined packet number, and is composed of, for example, 32 bits. The packet number is preferably initialized once per second. By defining the unique header in this way, a unique identifier can be constructed using the time and packet number, and packets transferred across the IP network 800 can be uniquely identified.

[0033] FIG. 4 is a flowchart of a process for adding a unique header according to the first embodiment of the present invention.

[0034] When the receiver 111 receives a packet (400), the unique header adder 112 acquires the current time (401) and compares the current time with the time of the previous packet reception (402). As mentioned above, the time is expressed in Unix Time.

[0035] If the current time and the previous packet reception time are different (false in 403), the unique header adding unit 112 initializes the packet number to 1 (404) and updates the previous packet reception time to the current time (405). On the other hand, if the current time and the previous packet reception time are the same (true in 403), steps 404 and 405 are not executed, and the process proceeds to step 406.

[0036] Then, the unique header adding unit 112 creates a unique header from the current time and packet number (406), and increments the packet number by 1 (407).

[0037] FIG. 5 is a flowchart of a process executed by the destination determination module 126 according to the first embodiment of the present invention when a packet is received.

[0038] When any of the receiving units 124a to 124c receives a packet from the IP network 800 (500), the destination determining unit 126 checks the destination of the IP packet in the received redundant packet and determines whether or not it has route information to the destination (501). It is preferable to determine whether or not it has route information to the destination by checking whether or not it is registered as a destination address to which the transmitting unit 121 of the packet forwarding device 100 is connected.

[0039] As a result, if the route information to the destination is available (true in 502), it is necessary to determine whether the packet is a duplicate packet, and so the destination determination unit 126 transfers the received packet to the duplicate packet determination unit 123 (503). The packet transferred to the duplicate packet determination unit 123 is determined to be a packet having the same information, the unique header is deleted, and the packet is transmitted from the transmission unit 121 to a network device of the user network 900.

[0040] On the other hand, if route information to the destination is not available (false in 502), the received packet needs to be forwarded to another packet forwarding device, so the destination determination unit 126 forwards the received packet to the packet duplication unit 113 (504). The packet forwarded to the packet duplication unit 113 is duplicated to generate redundant packets, and the generated redundant packets are transmitted from multiple transmission units 114a, 114b, and 114c to the packet forwarding devices on communication paths 801, 802, and 811.

[0041] FIG. 6 is a flowchart of a process executed by the duplicate packet determination unit 123 according to the first embodiment of the present invention when a packet is received.

[0042] When the duplicate packet determination unit 123 receives a packet (600), it compares the unique header of the received packet with the packet reception record stored in the packet reception history storage unit 125, and determines whether the received packet is a redundant packet that has already been received (601).

[0043] As a result, if the packet has already been received (true in 602), a packet having the same information has arrived, and therefore the duplicate packet determining unit 123 discards the packet (603).

[0044] On the other hand, if the packet has not been received (false in 602), a packet having the same information has not arrived, so the duplicate packet determination unit 123 transfers the redundant packet to the unique header deletion unit 122 (604) and records the packet number in the packet reception history storage unit 125 (605).

[0045] As described above, the packet forwarding device 100 of the first embodiment of the present invention includes packet sending units 114a to 114c that send packets with an identifier (unique header) that can determine the packet order and packets that have the same information, a destination determination unit 126 that determines the destination of the packet, and a duplicate packet determination unit 123 that determines packets that have the same information by referring to the identifier. Therefore, even if the communication path between packet forwarding devices is interrupted, communication can continue without interruption by forwarding packets to another packet forwarding device.

[0046] <Example 2> Next, a second embodiment of the present invention will be described. In the second embodiment, the configuration of the packet forwarding device is different from that of the first embodiment described above. In the first embodiment, packets are duplicated each time they pass through the packet forwarding device, which increases the load on the IP network. In the second embodiment, a packet forwarding device that can reduce the load on the IP network will be described. Note that in the second embodiment, differences from the first embodiment described above will be mainly described, and descriptions of the same configuration and processing as in the first embodiment will be omitted.

[0047] 7 is a diagram showing the configuration of a packet forwarding device 100 according to a second embodiment of the present invention. The configuration of the packet forwarding device 100 is the same as that of the packet forwarding devices 101 and 200.

[0048] The packet forwarding device 100 has a plurality of packet forwarding units 110 and 120. The packet forwarding units 110 and 120 are the same as the packet forwarding unit 110 in the first embodiment described above.

[0049] The packet forwarding unit 120 forwards packets from the IP network 800 to the user network 900, and includes a transmitting unit 121, a unique header deletion unit 122, a duplicate packet determination unit 123, multiple receiving units 124a, 124b, and 124c, a packet reception history storage unit 125, a destination determination unit 126, a survival hop count determination unit 127, and a survival hop count change unit 128.

[0050] The destination determination unit 126 checks the destination of an IP packet received from the IP network 800, and transfers a received packet having route information to the destination to the duplicate packet determination unit 123, and transfers a received packet having no route information to the destination to the number of surviving hops determination unit 127. The number of surviving hops determination unit 127 determines the number of surviving hops in the unique header, discards a received packet whose number of surviving hops is 0, and transfers a received packet whose number of surviving hops is 1 or more to the number of surviving hops modification unit 128. The number of surviving hops modification unit 128 modifies the number of surviving hops in the unique header of the received packet by decrementing it by 1, and transfers the packet with the modified number of surviving hops to the packet duplication unit 113. The components of the packet forwarding unit 120 other than those described above (the transmitting unit 121, the unique header deletion unit 122, the duplicate packet determination unit 123, the multiple receiving units 124a, 124b, 124c, and the packet reception history storage unit 125) are the same as those of the packet forwarding unit 120 of the first embodiment described above.

[0051] In the example of the configuration of the packet forwarding device 100 described above, the number of surviving hops determining unit 127 and the number of surviving hops changing unit 128 are provided in the packet forwarding unit 120 on the receiving side, but they may also be provided in the packet forwarding unit 110 on the transmitting side.

[0052] FIG. 8 is a diagram showing the structure of a packet to which a unique header is added and which is transmitted to an IP network 800 according to the second embodiment of the present invention.

[0053] The unique header of the second embodiment of the present invention includes a packet identifier 1 and a packet identifier 2. Packet identifier 1 includes time information in seconds and time information in milliseconds, and is composed of, for example, 32 bits. The time information is preferably represented in Unix Time, but may be represented in other formats. Packet identifier 2 includes a surviving hop count and a sequentially determined packet number, and is composed of, for example, 32 bits. The surviving hop count is determined by the surviving hop count determination unit 127, and is used to discard packets with a value less than 1. The packet number is preferably initialized once per second. By defining the unique header in this way, a unique identifier can be configured using the time and packet number, and packets transferred through the IP network 800 can be uniquely identified.

[0054] FIG. 9 is a flowchart of a process executed by the destination determination module 126 according to the second embodiment of the present invention when a packet is received.

[0055] When any of the receivers 124a to 124c receives a packet from the IP network 800 (510), the destination determination unit 126 checks the destination in the IP packet of the received redundant packet and determines whether or not it has route information to the destination (511). Whether or not it has route information to the destination can be determined by whether or not it is registered as a destination address to which the transmitter 121 of the packet forwarding device 100 is connected. As a result, if it has route information to the destination of the packet (true in 512), it transfers the received packet to the duplicate packet determination unit 123 to determine whether or not it is a duplicate packet (513). The packet transferred to the duplicate packet determination unit 123 is determined to be a packet with identical information, its unique header is deleted, and the packet is transmitted from the transmitter 121 to a network device of the user network 900.

[0056] On the other hand, if the route information to the destination of the packet does not exist (false in 512), the received packet is transferred to the number of surviving hops determination unit 127 in order to transfer the received packet to another packet transfer device (514). The route information to the destination determined by the destination determination unit 126 may be based on either an IP address or a network address.

[0057] FIG. 10 is a flowchart of a process executed by the number of surviving hops determination unit 127 according to the second embodiment of the present invention when a packet is received.

[0058] When the surviving hop count determination unit 127 receives a packet (700), it checks the surviving hop count in the unique header of the received packet and determines whether the surviving hop count is 1 or greater (701). As a result, if the surviving hop count is 1 or greater (true in 702), the surviving hop count determination unit 127 transfers the packet to the surviving hop count modification unit 128 (703). The surviving hop count of the packet transferred to the surviving hop count modification unit 128 is decremented by 1, and a redundant packet is generated by duplication in the packet duplication unit 113. The generated redundant packet is transmitted from multiple transmission units 114a, 114b, and 114c to packet forwarding devices on communication paths 801, 802, and 811.

[0059] On the other hand, if the number of surviving hops is less than 1 (false in 702), the packet is not forwarded to another packet forwarding device, and the packet is discarded (704).

[0060] As described above, the packet forwarding device 100 of the second embodiment of the present invention has, in addition to the configuration of the first embodiment, packet sending units 114a to 114c that send packets with an identifier (unique header) that can determine the number of surviving hops, the order of packets, and packets having the same information, and a number of surviving hops changing unit 128 that changes the number of surviving hops in the unique header. Therefore, in addition to the effect of the first embodiment, the number of times packets are forwarded between packet forwarding devices can be limited by the number of surviving hops assigned to the packets to be forwarded, thereby suppressing excessive packet forwarding.

[0061] Example 3 Next, a third embodiment of the present invention will be described. In the third embodiment, the configuration of the packet forwarding device is different from that of the first embodiment described above. In the first embodiment, in an environment where a packet forwarding device transmitted to another packet forwarding device cannot be received by a packet forwarding device other than the destination due to routing within the IP network or the like, the packet cannot be forwarded from the packet forwarding device other than the destination to the packet forwarding device of the destination. In the third embodiment, a packet forwarding device that enables packet forwarding from a packet forwarding device other than the destination to the packet forwarding device of the destination even in such a situation will be described. Note that in the third embodiment, differences from the first embodiment described above will be mainly described, and descriptions of the same configuration and processing as in the first embodiment will be omitted.

[0062] 11 is a diagram showing the configuration of a packet forwarding device 100 according to a third embodiment of the present invention. The configuration of the packet forwarding device 100 is the same as that of the packet forwarding devices 101 and 200.

[0063] The packet forwarding device 100 has a plurality of packet forwarding units 110 and 120, and a device information storage unit 131. The configuration of the packet forwarding unit 110 is the same as the packet forwarding unit 110 of the first embodiment described above, and the configuration of the packet forwarding unit 120 is the same as the packet forwarding unit 120 of the first embodiment described above.

[0064] FIG. 12 is a diagram showing information stored in the device information storage unit 131 according to the third embodiment of the present invention.

[0065] The device information storage unit 131 holds device information in which a device ID is associated with IP addresses 1 to M. The device ID is identification information for identifying the packet forwarding device. IP addresses 1 to M are IP addresses of the packet forwarding device, and correspond to interfaces connected to each IP network in the IP network 800. That is, in the device information storage unit 131 of the third embodiment, the IP addresses of the transmitters 114a, etc. of the packet forwarding device 100 and the IP addresses of the receivers of other packet forwarding devices facing the transmitters 114a, etc. are recorded in association with each other. Note that one column of the device information storage unit 131 (for example, the column of IP address M) may record the IP address of the receiver 111 of the packet forwarding device 100 and the IP address of the transmitter of the other packet forwarding device facing the receiver in association with each other. The IP addresses may be written in IPv4 or IPv6.

[0066] When the packet duplication unit 113 of the third embodiment of the present invention receives a packet from the unique header addition unit 112 or the destination determination unit 126, it refers to the device information storage unit 131 and transfers the packet to multiple IP addresses of multiple packet forwarding devices. For example, when outputting a packet from the transmission unit 114a, the packet duplication unit 113 refers to the column of IP address 1 corresponding to the transmission unit 114a, obtains the IP address of the row of the packet forwarding device that is the destination of the packet, and sets the obtained IP address in the transmitted packet.

[0067] As described above, the packet forwarding device 100 of the third embodiment of the present invention has, in addition to the configuration of the first embodiment, a device information storage unit 131 that stores the device ID and IP address of the packet forwarding device, and the packet duplication unit 113 refers to the device information storage unit and duplicates packets to all packet forwarding devices except for itself, so that it can receive and forward packets even in an environment where other packet forwarding devices cannot receive packets addressed to them due to routing within the IP network, etc.

[0068] Example 4 Next, a fourth embodiment of the present invention will be described. The fourth embodiment differs from the third embodiment in the configuration of the packet forwarding device, and is a combination of the second and third embodiments. In the third embodiment, packets are duplicated each time they pass through the packet forwarding device, which increases the load on the IP network. In the fourth embodiment, a packet forwarding device that can reduce the load on the IP network will be described. Note that in the fourth embodiment, differences from the third embodiment will be mainly described, and descriptions of the same configuration and processing as the third embodiment will be omitted. is.

[0069] 13 is a diagram showing the configuration of a packet forwarding device 100 according to a fourth embodiment of the present invention. The configuration of the packet forwarding device 100 is the same as that of the packet forwarding devices 101 and 200.

[0070] The packet forwarding device 100 has a plurality of packet forwarding units 110 and 120, and a device information storage unit 131. The configuration of the packet forwarding unit 110 is the same as that of the packet forwarding unit 110 in the first embodiment described above.

[0071] The packet forwarding unit 120 forwards packets from the IP network 800 to the user network 900, and includes a transmitting unit 121, a unique header deletion unit 122, a duplicate packet determination unit 123, multiple receiving units 124a, 124b, and 124c, a packet reception history storage unit 125, a destination determination unit 126, a survival hop count determination unit 127, and a survival hop count change unit 128.

[0072] The destination determination unit 126 checks the destination of an IP packet received from the IP network 800, and transfers a received packet having route information to the destination to the duplicate packet determination unit 123, and transfers a received packet having no route information to the destination to the number of surviving hops determination unit 127. The number of surviving hops determination unit 127 determines the number of surviving hops in the unique header, discards a received packet whose number of surviving hops is 0, and transfers a received packet whose number of surviving hops is 1 or more to the number of surviving hops modification unit 128. The number of surviving hops modification unit 128 modifies the number of surviving hops in the unique header of the received packet by decrementing it by 1, and transfers the packet with the modified number of surviving hops to the packet duplication unit 113. The components of the packet forwarding unit 120 other than those described above (the transmitting unit 121, the unique header deletion unit 122, the duplicate packet determination unit 123, the multiple receiving units 124a, 124b, 124c, and the packet reception history storage unit 125) are the same as those of the packet forwarding unit 120 of the first embodiment described above.

[0073] In the example of the configuration of the packet forwarding device 100 described above, the number of surviving hops determining unit 127 and the number of surviving hops changing unit 128 are provided in the packet forwarding unit 120 on the receiving side, but they may also be provided in the packet forwarding unit 110 on the transmitting side.

[0074] The unique header of the fourth embodiment of the present invention is the same as the unique header of the second embodiment (FIG. 8), and includes the number of surviving hops.

[0075] The destination determination module 126 of the fourth embodiment is the same as the destination determination module 126 of the second embodiment (see FIG. 9).

[0076] The number of surviving hops determining unit 127 of the fourth embodiment is the same as the number of surviving hops determining unit 127 of the second embodiment (see FIG. 10).

[0077] When the packet replicating unit 113 of the fourth embodiment receives a packet from the unique header adding unit 112 or the number of surviving hops changing unit 128, the packet replicating unit 113 refers to the device information storing unit 131 and transfers the packet to a plurality of IP addresses of a plurality of packet transfer devices.

[0078] As described above, the packet forwarding device 100 of the fourth embodiment of the present invention has, in addition to the configuration of the third embodiment, packet sending units 114a to 114c that send packets with an identifier (unique header) that can determine the number of surviving hops, the order of packets, and packets having the same information, and a number of surviving hops changing unit 128 that changes the number of surviving hops in the unique header. Therefore, in addition to the effect of the third embodiment, the number of times packets are forwarded between packet forwarding devices can be limited by the number of surviving hops assigned to the packets to be forwarded, thereby suppressing excessive packet forwarding.

[0079] <Example 5> Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, the configuration of the packet forwarding device is different from that of the third embodiment described above. In the third embodiment, when multiple packet forwarding devices have route information to the same user network, the multiple packet forwarding devices transmit the same packet to the user network. In the fifth embodiment, a packet forwarding device in which multiple packet forwarding devices transmit only one identical packet to the user network even in such a case will be described. Note that in the fifth embodiment, differences from the third embodiment described above will be mainly described, and descriptions of the configuration and processing that are the same as those of the third embodiment will be omitted.

[0080] 14 is a diagram showing the configuration of a packet forwarding device 100 according to a fifth embodiment of the present invention. The configuration of the packet forwarding device 100 is the same as that of the packet forwarding devices 101 and 200.

[0081] The packet forwarding device 100 has a plurality of packet forwarding units 110 and 120 and a device information storage unit 131. The configuration of the packet forwarding unit 110 is the same as the packet forwarding unit 110 of the third embodiment described above, except that the unique header adding unit 112 is connected to the device information storage unit 131, and the configuration of the packet forwarding unit 120 is the same as the packet forwarding unit 120 of the third embodiment described above.

[0082] FIG. 15 is a diagram showing information stored in the device information storage unit 131 according to the fifth embodiment of the present invention.

[0083] The device information storage unit 131 holds device information in which a device ID, IP addresses 1 to M, and user network addresses are associated with each other. The device ID is identification information for identifying the packet forwarding device. IP addresses 1 to M are IP addresses of the packet forwarding device, and correspond to interfaces connecting to each network in the IP network 800. The user network addresses are network addresses of user networks 901, 902, and 911, and are used to identify the packet forwarding device from the destination of a packet received by the packet forwarding device from the user network. That is, the device information storage unit 131 of the fifth embodiment stores the IP addresses of the transmitters 114a, etc. of the packet forwarding device 100 and the IP addresses of the receivers of other packet forwarding devices opposite the transmitters 114a, etc., in association with each other. Note that one column of the device information storage unit 131 (for example, the column of IP address M) may store the IP address of the receiver 111 of the packet forwarding device 100 and the IP address of the transmitter of the other packet forwarding device opposite the receiver in association with each other. The IP address may be expressed in either IPv4 or IPv6, and there may be one or more user network addresses for each device ID.

[0084] FIG. 16 is a diagram showing the structure of a packet to which a unique header is added and which is transmitted to the IP network 800 according to the fifth embodiment of the present invention.

[0085] The unique header of the fifth embodiment of the present invention includes a packet identifier 1 and a packet identifier 2. Packet identifier 1 includes time information in seconds and time information in milliseconds, and is composed of, for example, 32 bits. The time information may be expressed in Unix Time, but other formats are also acceptable. Packet identifier 2 includes a destination device ID and a sequentially determined packet number, and is composed of, for example, 32 bits. The packet number is preferably initialized once per second. By defining the unique header in this way, a unique identifier can be constructed using the time and packet number, and packets transferred through the IP network 800 can be uniquely identified.

[0086] When the unique header adding unit 112 of the fifth embodiment of the present invention receives a packet, it checks whether the destination of the received packet is a user network address stored in the device information storage unit 131, and identifies the device ID. The unique header adding unit 112 adds a unique header to the packet, in which the ID of the destination device of the unique header is recorded.

[0087] FIG. 17 is a flowchart of a process executed by the destination determination module 126 according to the fifth embodiment of the present invention when a packet is received.

[0088] When any of the receiving units 124a to 124c receives a packet from the IP network 800 (520), the destination determining unit 126 checks the unique header of the received redundant packet and determines whether the destination device ID is its own device ID (521).

[0089] As a result, if the destination device ID is its own device ID (true in 522), it is necessary to determine whether the packet is a duplicate packet, so the destination determination unit 126 transfers the received packet to the duplicate packet determination unit 123 (523). The packet transferred to the duplicate packet determination unit 123 is determined to be a packet having the same information, the unique header is deleted, and the packet is transmitted from the transmission unit 121 to a network device of the user network 900.

[0090] On the other hand, if the destination device ID is not its own device ID (false in 522), the received packet needs to be forwarded to another packet forwarding device, so the destination determination unit 126 forwards the received packet to the packet duplication unit 113 (524). The packet forwarded to the packet duplication unit 113 is duplicated to generate redundant packets, and the generated redundant packets are transmitted from multiple transmission units 114a, 114b, and 114c to the packet forwarding devices on communication paths 801, 802, and 811.

[0091] When the packet duplication unit 113 of the fifth embodiment of the present invention receives a packet from the unique header addition unit 112 or the destination determination unit 126, it refers to the device information storage unit 131 and transfers the packet to multiple IP addresses of multiple packet forwarding devices. For example, when outputting a packet from the transmission unit 114a, the packet duplication unit 113 refers to the column of IP address 1 corresponding to the transmission unit 114a, obtains the IP address of the row of the packet forwarding device that is the destination of the packet, and sets the obtained IP address in the transmitted packet.

[0092] As described above, the packet forwarding device 100 of the fifth embodiment of the present invention has the same configuration as the third embodiment, and is connected to a unique header adding unit 112 and a device information storage unit 131. The device information storage unit 131 holds the device ID, IP address, and user network address of the packet forwarding device. The unique header adding unit 112 adds the destination device ID to the unique header by referring to the destination of the received packet and the device information storage unit 131. The destination determination unit 126 determines whether the destination device ID is its own or not, thereby determining whether the packet should be forwarded to a user network or an IP network. This makes it possible to prevent the same packet from being forwarded to a user network even in an environment where multiple packet forwarding devices have the same route information.

[0093] Example 6 Next, a sixth embodiment of the present invention will be described. The sixth embodiment differs from the fifth embodiment in the configuration of the packet forwarding device, and is a combination of the second and fifth embodiments. In the fifth embodiment, packets are duplicated each time they pass through a packet forwarding device, which increases the load on the IP network. In the sixth embodiment, a packet forwarding device that can reduce the load on the IP network will be described. Note that in the second embodiment, differences from the second and fifth embodiments will be mainly described, and descriptions of the same configurations and processes as the second and fifth embodiments will be omitted.

[0094] 18 is a diagram showing the configuration of a packet forwarding device 100 according to a sixth embodiment of the present invention. The configuration of the packet forwarding device 100 is the same as that of the packet forwarding devices 101 and 200.

[0095] The packet forwarding device 100 has a plurality of packet forwarding units 110 and 120 and a device information storage unit 131. The configuration of the packet forwarding unit 110 is the same as that of the packet forwarding unit 110 of the fifth embodiment described above.

[0096] The packet forwarding unit 120 forwards packets from the IP network 800 to the user network 900, and includes a transmitting unit 121, a unique header deleting unit 122, a duplicate packet determining unit 123, multiple receiving units 124a, 124b, and 124c, a packet reception history saving unit 125, a destination determining unit 126, a number of surviving hops determining unit 127, and a number of surviving hops changing unit 128. The configuration of the packet forwarding unit 120 is the same as that of the packet forwarding unit 120 of the second embodiment described above.

[0097] In the example of the configuration of the packet forwarding device 100 described above, the number of surviving hops determining unit 127 and the number of surviving hops changing unit 128 are provided in the packet forwarding unit 120 on the receiving side, but they may also be provided in the packet forwarding unit 110 on the transmitting side.

[0098] FIG. 19 is a diagram showing the structure of a packet to which a unique header according to the sixth embodiment of the present invention is added and which is transmitted to the IP network 800.

[0099] The unique header of the sixth embodiment of the present invention includes a packet identifier 1, a packet identifier 2, and forwarding information. The packet identifier 1 includes time information in seconds and time information in milliseconds, and is composed of, for example, 32 bits. The time information may be expressed in Unix Time, but other formats are also acceptable. The packet identifier 2 includes a fixed value and a sequentially determined packet number, and is composed of, for example, 32 bits. The packet number may be initialized once per second. The forwarding information includes a destination device ID and a surviving hop count, and is composed of, for example, 32 bits. The surviving hop count is determined by the surviving hop count determination unit 127, and is used to discard packets with a value less than 1. By defining the unique header in this way, a unique identifier can be configured using the time and packet number, and packets forwarded on the IP network 800 can be uniquely identified.

[0100] FIG. 20 is a flowchart of a process executed by the destination determination module 126 according to the sixth embodiment of the present invention when a packet is received.

[0101] When any of the receiving units 124a to 124c receives a packet from the IP network 800 (530), the destination determining unit 126 checks the unique header of the received packet and determines whether the destination device ID is its own device ID (531).

[0102] As a result, if the destination device ID is its own device ID (true in 532), it is necessary to determine whether the packet is a duplicate packet, and therefore the destination determination unit 126 transfers the received packet to the duplicate packet determination unit 123 (533).

[0103] On the other hand, if the destination device ID is not its own device ID (false in 532), the received packet needs to be forwarded to another packet forwarding device, so the destination determination unit 126 forwards the received packet to the number of surviving hops determination unit 127 (534).

[0104] The process executed by the number of surviving hops determination unit 127 according to the sixth embodiment of the present invention is the same as the process executed by the number of surviving hops determination unit 127 according to the second embodiment (FIG. 10).

[0105] As described above, the packet forwarding device 100 of the sixth embodiment of the present invention has, in addition to the configuration of the fifth embodiment, packet sending units 114a to 114c that send packets with an identifier (unique header) that can determine the number of surviving hops, the order of packets, and packets having the same information and destination device ID, and a number of surviving hops changing unit 128 that changes the number of surviving hops in the unique header. Therefore, in addition to the effect of the fifth embodiment, the number of packet forwardings between packet forwarding devices can be limited by the number of surviving hops assigned to the packets to be forwarded, thereby suppressing excessive packet forwarding.

[0106] The present invention is not limited to the above-described embodiments, but includes various modifications and equivalent configurations within the spirit and scope of the appended claims. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to configurations including all of the described configurations. Furthermore, part of the configuration of one embodiment may be replaced with the configuration of another embodiment. Furthermore, the configuration of another embodiment may be added to the configuration of one embodiment. Furthermore, part of the configuration of each embodiment may be added, deleted, or replaced with other configurations.

[0107] Furthermore, the aforementioned configurations, functions, processing units, processing means, etc. may be realized in part or in whole in hardware, for example by designing them as integrated circuits, or may be realized in software by having a processor interpret and execute a program that realizes each function.

[0108] Information such as programs, tables, and files that realize each function can be stored in a storage device such as a memory, a hard disk, or an SSD (Solid State Drive), or in a recording medium such as an IC card, an SD card, or a DVD.

[0109] In addition, the control lines and information lines shown are those that are considered necessary for explanation, and do not necessarily represent all the control lines and information lines that are necessary for implementation. In reality, it can be assumed that almost all components are interconnected. [Explanation of symbols]

[0110] 100, 101, 200: Packet forwarding devices 110: Redundant packet transmission function unit 111: User packet receiver 112: Original header addition section 113: Packet duplication unit 114: Redundant packet transmitter 120: Redundant packet receiving function unit 121: User packet transmitter 122: Unique header deletion section 123: Overlapping packet determination unit 124: Redundant packet receiver 125: Packet reception history storage unit 126: Destination determination unit 127: Survival hop count determination unit 128: Survival hop count change section 131:Device information storage section 301, 302, 311: Network equipment 800: IP network 801, 802, 811: communication paths 900, 901, 902, 911: User network

Claims

1. A packet forwarding device that forwards packets via a plurality of independent communication paths provided between opposing packet forwarding devices, a user packet receiving unit that receives packets from other network devices; a user packet transmitting unit for transmitting packets to other network devices; an adding unit that adds an identifier to a packet, which allows the order of the packets and packets having the same information to be determined; a destination determination unit that determines a destination of the packet; a replicating unit that replicates the packet to which the identifier is added; a redundant packet transmitting unit that transmits the duplicated packets to each of the plurality of communication paths; a duplication determination unit that determines packets having the same information by referring to the identifier; the destination determination unit determines whether it has route information to the destination of the received packet; the user packet transmitting unit transfers the packet determined to have route information to the destination to a specific network device; The packet forwarding device is characterized in that the redundant packet transmitting unit forwards a packet determined not to have route information to a destination to all packet forwarding devices with which communication is possible.

2. 2. The packet forwarding device according to claim 1, a survival hop number changing unit that changes the survival hop number; a survival hop count determination unit that refers to the survival hop count and determines whether to discard a received packet, the adding unit adds to the packet an order of the packets, an identifier by which packets having the same information can be identified, and the number of surviving hops; The packet forwarding device is characterized in that the survival hop count changing unit changes the survival hop count of a packet to be forwarded to another packet forwarding device.

3. 2. The packet forwarding device according to claim 1, A packet forwarding device comprising: a device information storage unit for storing information about packet forwarding devices within a system.

4. 4. The packet forwarding device according to claim 3, The packet forwarding device, wherein the replicating unit refers to the device information storage unit and sets the destination of the packet forwarding device in the replicated packet.

5. 4. The packet forwarding device according to claim 3, the device information storage unit stores destinations of user networks connected to the packet forwarding device; The adding unit adds a destination device ID to the identifier by referring to the destination of the received packet and the device information storage unit in addition to the packet order and identity information; the replicating unit refers to the device information storage unit and sets the destination of the packet forwarding device in the replicated packet; the destination determination unit determines whether the destination device ID of the received packet is its own device ID; The packet forwarding device is characterized in that the user packet transmitting unit forwards to a specific network device a packet whose destination device ID is determined to be its own device ID.

6. A packet forwarding method in which a packet forwarding device forwards a packet, comprising: A plurality of independent communication paths are provided between the opposing packet forwarding devices, The packet forwarding method includes: A packet forwarding device on the transmitting side adds an identifier that enables the order of packets and packets having the same information to be determined, The transmitting packet forwarding device determines the destination of the packet; The packet forwarding device on the transmitting side copies the packet to which the identifier is added, the packet forwarding device on the transmitting side transmits the duplicated packets to each of the plurality of communication paths; A packet forwarding device on the receiving side determines the destination of the packet and determines packets having the same information by referring to the identifier, In the step of determining the destination, the packet forwarding device on the transmitting side determines whether it has route information to the destination of the received packet; A packet forwarding method characterized in that, in the procedure for transmitting the packets, the transmitting packet forwarding device forwards packets that are determined to have route information to the destination to a specific network device, and forwards packets that are determined not to have route information to the destination to all packet forwarding devices with which it can communicate.

7. A packet forwarding system for forwarding packets, comprising: a first packet forwarding device that transmits packets; a second packet forwarding device that receives packets from the first packet forwarding device; a plurality of independent communication paths are provided between the first packet forwarding device and the second packet forwarding device; The first packet forwarding device an adding unit that adds an identifier to a packet, which allows the order of the packets and packets having the same information to be determined; a replicating unit that replicates the packet to which the identifier is added; a redundant packet transmitting unit that transmits the duplicated packets to each of the plurality of communication paths; a destination determination unit that determines a destination of the packet; The second packet forwarding device a user packet transmitting unit for transmitting packets to other network devices; a redundant packet transmitting unit that transmits the duplicated packets to the plurality of communication paths; a duplication determination unit that determines packets having the same information by referring to the identifier; the destination determination unit determines whether it has route information to the destination of the received packet; the user packet transmitting unit transfers the packet determined to have route information to the destination to a specific network device; The packet forwarding system is characterized in that the redundant packet transmitting unit forwards a packet determined not to have route information to a destination to all packet forwarding devices with which communication is possible.

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