Packet forwarding device, packet forwarding method, and packet forwarding system

Abstract

To secure the reliability of communication while suppressing the consumption of communication resources.SOLUTION: Provided is a packet transfer device for transferring packets, with a plurality of communication paths provided between a packet transfer device and a counter packet transfer device that faces the former. The packet transfer device comprises an addition unit that adds an identifier with which it is possible to determine the sequence of packets and the packets having the same information, a replication unit that replicates the packet to which the identifier is added, a packet transmission unit that transmits the replicated packets to the plurality of communication paths, respectively, and a duplicate determination unit that refers to the identifier and determines the packets having the same information. The replication unit controls the number of packets transferred to and from the counter packet transfer device, on the basis of a communication environment between the packet transfer device and the counter packet transfer device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] There are packet forwarding devices that transmit one or more duplicated packets containing the same information to each of multiple independent communication paths. Such packet forwarding devices add information to distinguish the order of packets and identifiers to determine whether the packets contain the same information, and then transmit packets containing the same information to each communication path.

[0003] As background art in this technical field, for example, Patent Document 1 (JP 2006-174406 A) describes a packet forwarding method executed by packet forwarding devices provided on the packet sending side and receiving side in a communication network, in which two or more independent paths are set between the sending and receiving packet forwarding devices, the sending packet forwarding device inserts information for distinguishing the order of packets into a portion that is not referenced in determining the forwarding destination of the packet, copies the packet to generate two or more packets, and sends the packets to the independent paths, and the receiving packet forwarding device receives the packets from the independent paths and, by referring to the information for distinguishing the order of each packet, identifies packets having the same information and their order, and forwards one of the packets having the same information downstream in order according to the order of the packets.

[0004] In the background art described above, communication can continue even if a failure occurs in one of the communication paths. However, if the packet loss rate of a communication path is high, multiple independent communication paths must be prepared to continue communication, which increases costs. Therefore, one method for reducing the packet loss rate without increasing the number of independent communication paths is to send multiple packets containing the same information over the same communication path. By sending multiple packets containing the same information over the same path, communication can continue even if one of the packets is lost. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-174406 Summary of the Invention [Problem to be solved by the invention]

[0006] By using two methods, one of which is to send multiple packets containing the same information over a single communication path, and the other is to send multiple packets containing the same information over multiple communication paths, communication can continue even if a failure occurs on a communication path or if the packet loss rate is high. Furthermore, the reliability of communication improves in proportion to the number of packets containing the same information sent, but communication resources are used in proportion to the number of packets sent. If sufficient reliability can be ensured with only a specific communication path, or if the packet loss rate is sufficiently low even if the number of packets sent is reduced, excessive packets are sent, using more communication resources.

[0007] An object of the present invention is to provide a technique for suppressing consumption of communication resources while ensuring reliability in a packet transfer method that ensures communication reliability by transmitting multiple packets containing the same information. [Means for solving the problem]

[0008] A representative example of the invention disclosed in the present application is as follows: That is, a packet forwarding device for forwarding packets has a plurality of independent communication paths provided between it and an opposing packet forwarding device, the packet forwarding device comprising: an adding unit that adds an identifier capable of determining the order of packets and packets having identical information; a duplicating unit that copies packets having the identifier added; a packet transmitting unit that transmits the copied packets to each of the plurality of communication paths; and a duplication determining unit that determines packets having identical information by referring to the identifier; and the duplicating unit controls the number of packets transmitted between it and the opposing packet forwarding device based on the communication environment between them.

[0009] Furthermore, one example of a packet forwarding device according to the present invention is characterized in that it includes a calculation unit that calculates statistical information of received packets, the duplication determination unit records the communication path and the identifier of the packet received from the opposing packet forwarding device in a packet reception history, and the calculation unit refers to the packet reception history to calculate statistical information of the communication environment for each of the communication paths.

[0010] In addition, in the packet forwarding device according to one example of the present invention, the communication environment is a packet loss rate of the communication path.

[0011] Moreover, a packet forwarding device according to an embodiment of the present invention includes a setting change determination unit that generates setting change information by referring to the statistical information, and an information transmission unit that transmits the generated setting change information to the opposing packet forwarding device, wherein the setting change determination unit generates setting change information that reduces the number of packets transmitted on the communication path when it is determined that the packet loss rate is small as a result of comparing the packet loss rate of the communication path with a predetermined threshold, and generates setting change information that increases the number of packets transmitted on the communication path when it is determined that the packet loss rate is large as a result of comparing the packet loss rate of the communication path with the predetermined threshold.

[0012] In addition, in the packet forwarding device according to one example of the present invention, the communication environment is a delay time of the communication path.

[0013] Moreover, a packet forwarding device according to an embodiment of the present invention comprises a setting change determination unit that references the statistical information and generates setting change information, and an information transmission unit that transmits the generated setting change information to the opposing packet forwarding device, wherein the setting change determination unit generates setting change information that reduces the number of packets transmitted on a communication path other than the communication path when a state in which the delay time of a specific communication path is smallest among the delay times of all communication paths continues for a predetermined time, and generates setting change information that sets the number of packets transmitted on all communication paths to a predetermined maximum value if there are multiple communication paths that have the smallest delay time among the delay times of all communication paths within the predetermined time.

[0014] In addition, in the packet forwarding device according to one example of the present invention, the replicating unit changes the number of packets to be transmitted through the communication path in accordance with the received setting change information.

[0015] In addition, in one example of a packet forwarding method of the present invention, a transmitting packet forwarding device adds an identifier that can determine the order of packets and packets that have the same information, copies the packets to which the identifier has been added, and transmits each of the copied packets to the multiple communication paths, a receiving packet forwarding device determines packets that have the same information by referring to the identifier, and the transmitting packet forwarding device controls the number of packets to be sent between the transmitting packet forwarding device and the opposing packet forwarding device based on the communication environment between the transmitting packet forwarding device and the opposing packet forwarding device.

[0016] Furthermore, one example of a packet forwarding system according to the present invention comprises a first packet forwarding device that transmits packets and a second packet forwarding device that receives packets from the first packet forwarding device, and 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 has an adding unit that adds an identifier that enables determination of the order of packets and packets having identical information, a duplicating unit that copies packets having the identifier added, and a packet transmitting unit that transmits each of the copied packets to the plurality of communication paths, the duplicating unit controls the number of packets sent between the opposing packet forwarding device based on the communication environment between the opposing packet forwarding device, and the second packet forwarding device has a duplication determining unit that determines packets having identical information by referring to the identifier. [Effects of the Invention]

[0017] According to one aspect of the present invention, it is possible to reduce the consumption of communication resources while ensuring the reliability of communication. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0018] [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 when a packet is received in the first embodiment. [Figure 6] 10 is a flowchart of a process of transmitting an instruction to change the number of redundant packets caused by a packet loss rate according to the first embodiment. [Figure 7]10 is a flowchart of a process of transmitting an instruction to change the number of redundant packets caused by a delay time in the first embodiment. [Figure 8] FIG. 10 is a configuration diagram of a packet forwarding system according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] Example 1 FIG. 1 is a configuration diagram of a packet forwarding system according to a first embodiment of the present invention.

[0020] The packet forwarding system of this embodiment has opposing user networks 901 and 902, a packet forwarding device 100 on the user network 901 side, a packet forwarding device 200 on the user network 902 side, and an IP network 800 connecting the packet forwarding device 100 and the packet forwarding device 200. The IP network 800 has a plurality of independent communication paths 801, 802, and 803 that use different communication methods. The communication paths 801 to 803 may be configured as wireless networks or wired networks, or may be configured as wireless networks of different methods.

[0021] A plurality of terminals are connected to the user networks 901 and 902, and communication is performed between the terminals of the user network 901 and the terminals of the user network 902 via the IP network 800.

[0022] The packet forwarding device 100 forwards packets by referring to packet destination information while controlling the number of redundant packets transmitted on each of the communication paths 801 to 803 between the user network 901 and the IP network 800. Similarly, the packet forwarding device 200 forwards packets between the user network 902 and the IP network 800 while controlling the number of redundant packets transmitted on each of the communication paths 801 to 803.

[0023] Communications between the packet forwarding devices 100, 200 and the user networks 901, 902, and communications between the packet forwarding devices 100, 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, 200 may be fixedly installed devices or portable devices.

[0024] 2 is a diagram showing the configuration of the packet forwarding device 100. The configuration of the packet forwarding device 100 and the configuration of the packet forwarding device 200 are the same.

[0025] The packet forwarding device 100 has multiple packet forwarding units 110, 120, a statistical information calculation unit 131, a setting change determination unit 132, a transmission unit 133, and a reception unit 134. The reception unit 134 receives packet replication setting change information from outside the packet forwarding device 100 (for example, from the opposing packet forwarding device 200).

[0026] The packet forwarding unit 110 forwards packets from the user network 901 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 901. The unique header adding unit 112 adds a unique header to the packets input from the user network 901. 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 to 803 of the IP network 800, and transmit the generated redundant packets to the communication paths 801 to 803.

[0027] The packet forwarding unit 120 forwards packets from the IP network 800 to the user network 901, and includes a transmitting unit 121, a unique header removing unit 122, a duplicate packet determining unit 123, multiple receiving units 124a, 124b, 124c, and a packet reception history storage unit 125. The multiple receiving units 124a, 124b, 124c are provided corresponding to the communication paths 801 to 803 of the IP network 800, and receive packets 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 packets input from the IP network 800. The transmitting unit 121 transmits packets to the user network 901. The packet reception history storage unit 125 stores the packet reception history, which is the determination result by the duplicate packet determining unit 123.

[0028] The statistical information calculation unit 131 analyzes packets received from the IP network 800 and calculates statistical information for each of the communication paths 801-803. For example, the statistical information is the packet loss rate and delay time for each of the communication paths 801-803. The setting change determination unit 132 uses the calculated statistical information to generate packet replication setting change information including the number of packets (number of redundant packets) to be transmitted to the IP network 800. Details of the processing executed by the setting change determination unit 132 will be described with reference to Figs. 6 and 7. The transmission unit 133 transmits the generated packet replication setting change information to an external unit of the packet forwarding device 100 (for example, the opposing packet forwarding device 200).

[0029] In the configuration example described above, the setting change determination unit 132 is provided on the transmitting side, but it may also be provided on the receiving side. That is, the statistical information calculation unit 131 on the transmitting side transmits the calculated statistical information to the receiving side, and the setting change determination unit 132 on the receiving side generates packet replication setting change information.

[0030] In the IP network 800 of this embodiment, packets are transferred using the UDP protocol, but other protocols may also be used. For example, when the TCP / IP protocol is used, the packet transfer device on the sending side can measure the packet loss rate, so the number of packets (number of redundant packets) to be sent to the IP network 800 may be determined by the packet transfer device on the sending side.

[0031] 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. As shown in FIG.

[0032] 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.

[0033] The UDP header includes a source port number, a destination port number, a packet length, and a checksum.

[0034] 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 may be expressed in Unix Time, but other formats are also acceptable (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.

[0035] FIG. 4 is a flowchart of the process of adding a unique header.

[0036] 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.

[0037] If the current time and the previous packet reception time are different, it is determined that one second or more has passed (false in 403), and 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.

[0038] 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).

[0039] FIG. 5 is a flowchart of the process executed when a packet is received.

[0040] When any of the receiving units 124a to 124c receives a packet from the IP network 800 (500), the duplicate packet determining unit 123 compares the unique header of the received packet with the packet reception record stored in the packet reception history storing unit 125, and determines whether the received packet is a redundant packet that has already been received (501).

[0041] As a result, if the packet has already been received (true in 502), a packet having the same information has already arrived via some route, so the duplicate packet determination unit 123 determines whether a packet identical to the received packet has already been received via the communication route via which the received packet passed (503). If the same packet has not been received (false in 504), the duplicate packet determination unit 123 calculates the delay time from the time in the unique header of the received packet and the current time (505), and records the communication route and delay time of the received packet in the packet reception history storage unit 125 (506). On the other hand, if the same packet has been received (true in 504), the duplicate packet determination unit 123 discards the packet (507).

[0042] On the other hand, if the packet has not been received (false in 502), 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 (508), calculates the delay time from the time in the unique header of the received packet and the current time (509), and records the packet number, the communication path of the received packet, and the delay time in the packet reception history storage unit 125 (510).

[0043] FIG. 6 is a flowchart of a process for transmitting an instruction to change the number of redundant packets due to a packet loss rate.

[0044] The setting change determination unit 132 checks the statistical information of the packet loss rate for each communication path calculated by the statistical information calculation unit 131 (601). If the packet loss rate is equal to or less than a predetermined threshold (true in 602), the setting change determination unit 132 determines that the communication path is stable. The setting change determination unit 132 determines whether the packet replication setting is the initial value (603). If the packet replication setting is the initial value (true in 603), the setting change determination unit 132 generates packet replication setting change information to reduce the number of redundant packets transmitted on the communication path, and the transmission unit 133 transmits the generated packet replication setting change information (604). In this embodiment, the initial value of the packet replication setting is a maximum value of 3, and the number of redundant packets is reduced in a communication path with a small and stable packet loss rate, thereby improving communication efficiency. If the packet replication setting is not the initial value (false in 603), the number of redundant packets is already smaller than the initial value, so the setting change determination unit 132 does not generate packet replication setting change information and returns to step 601.

[0045] On the other hand, if the packet loss rate is greater than the predetermined threshold (false in 602), the communication path is unstable, so it is determined whether the packet replication setting is at its initial value (605). If the packet replication setting is not at its initial value (false in 605), the setting change determination unit 132 generates packet replication setting change information that corrects the number of redundant packets to be transmitted on the communication path to its initial value, and the transmission unit 133 transmits the generated packet replication setting change information (606). In this embodiment, the initial value of the packet replication setting is a maximum value of 3, and if the number of redundant packets on an unstable communication path is smaller than the initial value, the number of redundant packets is set to the initial value to improve communication stability. On the other hand, if the packet replication setting is at its initial value (true in 605), the number of redundant packets is already at its maximum value, so packet replication setting change information is not generated and the process returns to step 601.

[0046] FIG. 7 is a flowchart of a process for transmitting an instruction to change the number of redundant packets caused by a delay time.

[0047] The setting change determination unit 132 checks the statistical information of the delay time for each communication path calculated by the statistical information calculation unit 131 and determines whether the state in which the delay time for a specific communication path is minimized continues for a predetermined time (702). If the state in which the delay time for a specific communication path is minimized continues for a predetermined time (true in 702), the delay on the specific communication path is always small, so the setting change determination unit 132 determines whether the packet replication setting is at its initial value (703). If the packet replication setting is at its initial value (true in 703), the setting change determination unit 132 generates packet replication setting change information that reduces the number of redundant packets transmitted on a communication path other than the specific communication path, and the transmission unit 133 transmits the generated packet replication setting change information (704). In this embodiment, the initial value of the packet replication setting is a maximum value of 3. In a communication path with a small and stable delay time, subsequent packets are simply discarded, so the number of redundant packets is reduced and communication efficiency is improved. If the packet duplication setting is not the initial value (false in 703), the number of redundant packets is already smaller than the initial value, so the setting change determining unit 132 returns to step 701 without generating packet duplication setting change information.

[0048] On the other hand, if the state in which the delay time on a specific communication path is minimized has not continued for a predetermined time (702: false), there are multiple communication paths with the minimum delay time during that predetermined time, so it is determined whether the packet replication setting is at its initial value (705). If the packet replication setting is not at its initial value (705: false), the setting change determination unit 132 generates packet replication setting change information that corrects the number of redundant packets to be transmitted on all communication paths to its initial value, and the transmission unit 133 transmits the generated packet replication setting change information (706). In other words, the number of redundant packets is set to the initial value of 3, thereby reducing the communication delay time. On the other hand, if the packet replication setting is at its initial value (705: true), the number of redundant packets is already at its maximum value, so the process returns to step 701 without generating packet replication setting change information.

[0049] Alternatively, the packet forwarding devices 100 and 200 may transmit the packet reception history to an external device, and the external device may be provided with the statistical information calculation unit 131 and the setting change determination unit 132, so that the external device generates packet replication setting change information.

[0050] Furthermore, the packet forwarding devices 100 and 200 may transmit the statistical information calculated by the statistical information calculation unit 131 to an external device, and the external device may be provided with a setting change determination unit 132, so that the external device generates packet replication setting change information.

[0051] <Example 2> Next, a second embodiment of the present invention will be described. In the second embodiment, the configuration of the packet forwarding system is different from that of the first embodiment described above, but the configurations and operations of the packet forwarding devices 100 and 200 are the same. In the second embodiment, differences from the first embodiment will be mainly described, and the same configurations and processes as those in the first embodiment will be assigned the same reference numerals and their description will be omitted.

[0052] FIG. 8 is a configuration diagram of a packet forwarding system according to a second embodiment of the present invention.

[0053] The packet forwarding system of this embodiment has opposing user networks 901 and 902, a network device 301 on the user network 901 side, a packet forwarding device 100 on the user network 901 side, a network device 302 on the user network 902 side, a packet forwarding device 200 on the user network 902 side, and an IP network 800 connecting the packet forwarding device 100 and the packet forwarding device 200. The IP network 800 has communication paths 801, 802, and 803 of different communication methods. The communication paths 801 to 803 may be configured as wireless networks or wired networks, or may be configured as wireless networks of different methods.

[0054] A plurality of terminals are connected to the user networks 901 and 902, and communication is carried out between the terminals of the user network 901 and the terminals of the user network 902 via the IP network 800.

[0055] The network device 301 transfers packets transferred between the user network 901 and the IP network 800 to the packet forwarding device 100, and transfers packets transmitted from the packet forwarding device 100 to the user network 901 or the IP network 800. Similarly, the network device 302 transfers packets transferred between the user network 902 and the IP network 800 to the packet forwarding device 200, and transfers packets transmitted from the packet forwarding device 200 to the user network 902 or the IP network 800.

[0056] The packet forwarding device 100 forwards packets between the user network 901 and the IP network 800 via the network equipment 301 while controlling the number of redundant packets in each of the communication paths 801 to 803. Similarly, the packet forwarding device 200 forwards packets between the user network 902 and the IP network 800 via the network equipment 302 while controlling the number of redundant packets transmitted in each of the communication paths 801 to 803.

[0057] 8, by configuring the network devices 301, 302 and the packet forwarding devices 100, 200 separately, the number of communication IFs possessed by the packet forwarding devices 100, 200 may differ from the number of communication paths between the user networks 901, 902. In other words, by placing a network device that determines the communication path of a packet based on the destination IP address, destination port number, VLAN ID, etc. of the packet between the user networks 901, 902 and each of the communication paths 801 to 803, the number of communication IFs of the packet forwarding devices 100, 200 can be reduced (for example, to one).

[0058] As described above, the packet forwarding device 100 of the embodiment of the present invention includes a packet transmitting unit (transmitting units 114a to 114c) that transmits packets with an identifier (unique header) that can determine the order of packets and packets having the same information, a duplication determining unit (duplicate packet determining unit 123) that determines packets having the same information by referring to the identifier, and a duplication unit (packet duplication unit 113) that controls the number of packets sent between the opposing packet forwarding device 200 based on the communication environment with the opposing packet forwarding device 200. Therefore, since there are multiple communication paths, communication can continue even if a failure occurs on one communication path, and packets can arrive without retransmission even if packet loss occurs in any of the duplicated packets. Furthermore, transmission of unnecessary redundant packets can be suppressed while ensuring communication reliability, thereby suppressing consumption of communication resources.

[0059] It also includes a calculation unit (statistical information calculation unit 131) that calculates statistical information of received packets, and the duplicate packet determination unit 123 records the communication path and identifier of the packet received from the opposing packet forwarding device 200 in the packet reception history storage unit 125. The statistical information calculation unit 131 refers to the packet reception history storage unit 125 and calculates statistical information of the communication environment for each communication path, so that it can determine whether each communication path is stable or unstable.

[0060] The communication environment is the packet loss rate of the communication path, and includes a setting change determining unit 132 that generates setting change information by referring to statistical information, and an information transmitting unit that transmits the generated setting change information to the opposing packet forwarding device 200. (Transmitter 133) The setting change determination unit 132 compares the packet loss rate of the communication path with a predetermined threshold, and if it determines that the packet loss rate is small, generates setting change information to reduce the number of packets transmitted on the communication path. Conversely, if it compares the packet loss rate of the communication path with a predetermined threshold and it determines that the packet loss rate is large, it generates setting change information to increase the number of packets transmitted on the communication path. This reduces the number of identical packets flowing on a stable communication path, and reduces the load on the communication path.

[0061] The communication environment is a delay time of a communication path, and includes a setting change determining unit 132 that generates setting change information by referring to statistical information, and an information transmitting unit that transmits the generated setting change information to the opposing packet forwarding device 200. (Transmitter 133) When a state in which the delay time of a specific communication path is the smallest among the delay times of all the communication paths continues for a predetermined time, the setting change determination unit 132 generates setting change information to reduce the number of packets transmitted on a communication path other than the specific communication path, and when there are multiple communication paths with the smallest delay time among the delay times of all the communication paths within a predetermined time, the setting change determination unit 132 generates setting change information to set the number of packets transmitted on all the communication paths to a predetermined maximum value, thereby reducing the number of identical packets that do not affect the delay between the packet forwarding devices 100 and 200 and reducing the load on the communication paths.

[0062] In addition, the packet duplication unit 113 changes the number of packets to be sent on the communication path in accordance with the received setting change information, so that the number of packets can be controlled according to the status of each communication path, and the stability of the communication path and the number of packets (load on the communication path) can be adjusted.

[0063] 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.

[0064] 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 a processor interpreting and executing a program that realizes each function.

[0065] 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.

[0066] In addition, the control lines and information lines shown are those that are considered necessary for the explanation, and do not necessarily show all the control lines and information lines that are necessary for implementation. In reality, it can be considered that almost all components are interconnected. [Explanation of symbols]

[0067] 100, 200: Packet forwarding device 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 131:Statistical information calculation section 132: Setting change determination unit 133: Packet replication setting change information transmitter 134: Packet replication setting change information receiver 301, 302: Network equipment 800: IP network 811, 812, 813: Communication path 901, 902: User network

Claims

1. A packet forwarding device that forwards packets, A plurality of independent communication paths are provided between the opposing packet forwarding devices, The packet forwarding device an adding unit that adds an identifier that enables determination of the order of packets and packets having the same information; a replicating unit that replicates the packet to which the identifier is added; a 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 and records the communication path of the packet received from the opposing packet forwarding device and the identifier in a packet reception history; a calculation unit that refers to the packet reception history and calculates statistical information on a packet loss rate of packets received for each of the communication paths; a setting change determination unit that generates setting change information by referring to the statistical information; an information transmitting unit that transmits the generated setting change information to the opposing packet forwarding device; The setting change determination unit generating setting change information for reducing the number of packets transmitted on the communication path when the statistical information of the communication path is determined to be small as a result of comparing the statistical information of the communication path with a predetermined threshold value; generating setting change information for increasing the number of packets transmitted on the communication path when the statistical information of the communication path is determined to be large as a result of comparing the statistical information of the communication path with a predetermined threshold value; The packet forwarding device, wherein the replicating unit controls the number of packets transmitted over the communication path between the opposing packet forwarding device and the opposing packet forwarding device based on the setting change information.

2. A packet forwarding device for forwarding packets, comprising: A plurality of independent communication paths are provided between the opposing packet forwarding devices, The packet forwarding device an adding unit that adds an identifier that enables determination of the order of packets and packets having the same information; a replicating unit that replicates the packet to which the identifier is added; a 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 and records the communication path of the packet received from the opposing packet forwarding device and the identifier in a packet reception history; a calculation unit that refers to the packet reception history and calculates statistical information on delay times of packets received for each of the communication paths; a setting change determination unit that generates setting change information by referring to the statistical information; an information transmitting unit that transmits the generated setting change information to a peer packet forwarding device; The setting change determination unit When a state in which statistical information of a specific communication path is smallest among statistical information of all communication paths continues for a predetermined time, generating setting change information to reduce the number of packets transmitted on a communication path other than the specific communication path; If there are a plurality of communication paths for which the statistical information of all communication paths is smallest in the predetermined time, generating setting change information for setting the number of packets transmitted on all communication paths to a predetermined maximum value, The packet forwarding device is characterized in that the replicating unit controls the number of packets to be transmitted between the opposing packet forwarding device and the opposing packet forwarding device based on the setting change information.

3. 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 transmitting-side packet forwarding device adds an identifier that enables determination of the order of packets and packets having the same information, copies the packets to which the identifier has been added, and transmits each of the copied packets to the plurality of communication paths; The receiving packet forwarding device determining packets having the same information by referring to the identifier; recording the communication path and the identifier of the packet received from the packet forwarding device on the transmitting side in a packet reception history; calculating statistical information on a packet loss rate of packets received for each of the communication paths by referring to the packet reception history; generating setting change information for reducing the number of packets transmitted on the communication path when the statistical information of the communication path is determined to be small as a result of comparing the statistical information of the communication path with a predetermined threshold value; generating setting change information for increasing the number of packets transmitted on the communication path when the statistical information of the communication path is determined to be large as a result of comparing the statistical information of the communication path with a predetermined threshold value; transmitting the generated setting change information to the transmitting-side packet forwarding device; A packet forwarding method characterized in that the transmitting packet forwarding device controls the number of packets sent over the communication path between the transmitting packet forwarding device and the receiving packet forwarding device based on setting change information sent from the receiving packet forwarding device.

4. 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 transmitting-side packet forwarding device adds an identifier that enables determination of the order of packets and packets having the same information, copies the packets to which the identifier has been added, and transmits each of the copied packets to the plurality of communication paths; The receiving packet forwarding device determining packets having the same information by referring to the identifier; recording the communication path and the identifier of the packet received from the packet forwarding device on the transmitting side in a packet reception history; calculating statistical information on delay times of packets received for each of the communication paths by referring to the packet reception history; When a state in which statistical information of a specific communication path is smallest among statistical information of all communication paths continues for a predetermined time, generating setting change information to reduce the number of packets transmitted on a communication path other than the specific communication path; If there are a plurality of communication paths for which the statistical information of all communication paths is smallest in the predetermined time, generating setting change information for setting the number of packets transmitted on all communication paths to a predetermined maximum value, transmitting the generated setting change information to the transmitting-side packet forwarding device; A packet forwarding method characterized in that the transmitting packet forwarding device controls the number of packets sent between the receiving packet forwarding device and the transmitting packet forwarding device based on setting change information sent from the receiving packet forwarding device.

5. 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 that enables determination of the order of packets and packets having the same information; a replicating unit that replicates the packet to which the identifier is added; a packet transmitting unit that transmits each of the duplicated packets to the plurality of communication paths; The second packet forwarding device a duplication determination unit that determines packets having the same information by referring to the identifier and records the communication path of the packet received from the first packet forwarding device and the identifier in a packet reception history; a calculation unit that refers to the packet reception history and calculates statistical information on a packet loss rate of packets received for each of the communication paths; a setting change determination unit that generates setting change information by referring to the statistical information; an information transmitting unit that transmits the generated setting change information to the first packet forwarding device; The setting change determination unit of the second packet forwarding device generating setting change information for reducing the number of packets transmitted on the communication path when the statistical information of the communication path is determined to be small as a result of comparing the statistical information of the communication path with a predetermined threshold value; generating setting change information for increasing the number of packets transmitted on the communication path when the statistical information of the communication path is determined to be large as a result of comparing the statistical information of the communication path with a predetermined threshold value; A packet forwarding system characterized in that the replication unit of the first packet forwarding device controls the number of packets sent over the communication path between the first packet forwarding device and the second packet forwarding device based on the setting change information.

6. 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 that enables determination of the order of packets and packets having the same information; a replicating unit that replicates the packet to which the identifier is added; a packet transmitting unit that transmits each of the duplicated packets to the plurality of communication paths; The second packet forwarding device a duplication determination unit that determines packets having the same information by referring to the identifier and records the communication path of the packet received from the first packet forwarding device and the identifier in a packet reception history; a calculation unit that refers to the packet reception history and calculates statistical information on delay times of packets received for each of the communication paths; a setting change determination unit that generates setting change information by referring to the statistical information; an information transmitting unit that transmits the generated setting change information to the first packet forwarding device; The setting change determination unit of the second packet forwarding device When a state in which statistical information of a specific communication path is smallest among statistical information of all communication paths continues for a predetermined time, generating setting change information to reduce the number of packets transmitted on a communication path other than the specific communication path; If there are a plurality of communication paths for which the statistical information of all communication paths is smallest in the predetermined time, generating setting change information for setting the number of packets transmitted on all communication paths to a predetermined maximum value, A packet forwarding system, characterized in that the replication unit of the first packet forwarding device controls the number of packets sent between the first packet forwarding device and the second packet forwarding device based on the setting change information.

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