JP6036508B2 - COMMUNICATION SYSTEM, COMMUNICATION DEVICE, COMMUNICATION PROGRAM, AND COMMUNICATION METHOD - Google Patents

Description

  The present invention relates to communication in a network including a plurality of communication devices.

  In a network including a plurality of multicast groups, there may be redundant paths. When there is a redundant path, the multicast data transfer path can be distributed. For example, in a network managed using Protocol Independent Multicast-Sparse Mode (PIM-SM), a rendezvous point (RP) is set for each multicast group. The rendezvous point operates as a branch point of the distribution tree of multicast data, and is used to generate a route connecting the multicast data transmission source and the distribution destination. Therefore, when distributing multicast data to a plurality of routes, an operator determines a route to be used for transfer for each multicast group in advance, and sets a transfer device included in the route to be used for transfer as a rendezvous point. . Therefore, the operator manually sets a rendezvous point for each multicast group.

  As a related technology, a control device has been devised that can acquire multicast data distribution information by notification from a terminal that receives multicast data, and can identify the occurrence of a failure or congestion in the router by notification from each router. Yes. When a failure or congestion occurs in a router that is distributing multicast data, this control apparatus determines a switching destination router according to the multicast data distribution status (for example, Patent Document 1).

JP 2002-252630 A

  After the rendezvous point is set in order to distribute the multicast data transfer process, an amount of data that cannot be transferred using all redundant paths may be transmitted. In this case, since congestion occurs in any route, multicast data cannot be transferred. However, even in such a case, it is desirable not to interrupt communication related to data with relatively high priority.

  An object of one aspect of the present invention is to make it difficult to transfer data having a relatively high priority.

  The system according to the embodiment includes a first transfer device, a second transfer device connected to the first transfer device via a first route or a second route, and the first route in the first route A first communication device and a second communication device in the second path are provided. The first communication device identifies the priority and traffic rate of the data in association with the destination address of each data transferred from the first transfer device to the second transfer device. The first communication device reduces a difference in a total value of traffic rates between the first route and the second route, and prevents the total value in each route from exceeding a predetermined value. In addition, a route to be used for transfer is selected in order from data having a relatively high priority. The first communication device transfers the data selected by the first route as the transfer route to the second transfer device, and the destination address of the data selected by the second route as the transfer route is Notify the second communication device. The second communication device transfers data addressed to the destination address notified from the first communication device to the second transfer device.

  It becomes difficult to transfer data with a relatively high priority.

It is a figure explaining the example of a communication method. It is a figure explaining the example of a structure of a communication apparatus. It is a figure explaining the example of the hardware constitutions of a communication apparatus. It is a figure which shows the example of a network. It is a figure which shows the example of setting data. It is a figure which shows the example of in-transfer data information and RP setting information. It is a figure which shows the example of in-transfer data information and RP setting information. It is a figure explaining the example of the change of transfer data. It is a figure which shows the example of the information used when changing the transfer data. It is a figure explaining the example of the determination method of a priority. It is a figure which shows the example of delivery request information and RP setting information. It is a figure explaining the example of RP setting information. It is a figure explaining the example of the determination method of a priority. It is a flowchart explaining the example of a process of a communication apparatus. It is a flowchart explaining the example of the process which changes the allocation of data. It is a flowchart explaining the example of the data allocation method using a priority. It is a flowchart explaining the example of a process when distribution request information is received.

  FIG. 1 shows an example of a communication method. In the example of FIG. 1, there are transfer devices 10 a to 10 e in the network, multicast data transmission sources (nodes D1 to D3) are all connected to the transfer device 10 a, and multicast data distribution destinations (nodes R1 to R3) are Both are assumed to be connected to the transfer device 10e. Hereinafter, each multicast group is represented by a code including a numerical value for identifying the multicast group following the alphabet “MC”. For example, the multicast group 1 is indicated as “MC1”. Note that the numerical value at the end of the code attached to a node represents the multicast group to which the node belongs. For example, the node D1 and the node R1 belong to MC1. Furthermore, as will be described later, it is assumed that the number at the end of the code representing the rendezvous point is associated with the multicast group. It is assumed that there is a route passing through the communication device 20a and a route passing through the communication device 20b between the transfer device 10a and the transfer device 10b. Hereinafter, the amount of data that flows on a network per unit time may be referred to as a “traffic rate”. In the following description, it is assumed that the amount of data that flows through a specific route per second is represented by bps (Bits Per Second). Furthermore, the maximum traffic rate obtained by a certain route may be described as “maximum rate”.

  (A) The communication device 20a distributes the transfer route for multicast data distributed via the transfer device 10a. For this reason, the transfer apparatus 10a transfers the multicast data distributed via the transfer apparatus 10a to the communication apparatus 20a until the rendezvous point change setting is made. While the amount of data transferred from the transfer device 10a is a transferable amount, the communication device 20a determines the rendezvous point so that the difference in transfer amount between the paths becomes small. For example, as illustrated in FIG. 1A, it is assumed that the node D1 transmits data to be distributed to the multicast group MC1 to the transfer device 10a. Then, the transfer device 10a transfers the MC1 distribution data transmitted from the node D1 to the communication device 20a. Here, it is assumed that neither of the communication devices 20a and 20b transfers multicast data, and any communication device 20 can transfer data of MC1. Then, the communication device 20a sets a rendezvous point (RP1) for MC1 in the communication device 20a.

  (B) Next, it is assumed that the node D2 transmits data to the multicast group MC2. Distribution data addressed to MC2 is transferred to the communication device 20a via the transfer device 10a. Then, the communication device 20a determines, as a rendezvous point (RP2) of MC2, the communication device 20 included in the route with the lower traffic rate out of the route including the communication device 20a and the route including the communication device 20b. . Here, the communication device 20a transfers MC1 data, but the communication device 20b does not transfer multicast data. For this reason, the communication device 20a determines the communication device 20b to be RP2.

  (C) The communication device 20a requests the communication device 20b to transfer data of MC2. In response to a request from the communication device 20a, the communication device 20b sets the communication device 20b to a rendezvous point RP2 of data distributed by the MC2 and transfers multicast data as shown in FIG. 1B. In the subsequent processing, the transfer device 10a transfers the MC2 data to the communication device 20b.

  (D) Assume that the node D3 transmits data to the multicast group MC3. Distribution data addressed to MC3 is transferred from the transfer device 10a to the communication device 20a. Here, it is assumed that the maximum rate of the route including the communication device 20a is lower than the sum of the traffic rates of the distribution data of MC1 and the distribution data of MC3. Further, it is assumed that the maximum rate of the route including the communication device 20b is lower than the sum of the traffic rates of the distribution data of MC2 and the distribution data of MC3. In this case, distribution of data of any multicast group is stopped.

  Therefore, the communication device 20a compares the priority levels of the distribution data of the multicast groups MC1 to MC3. Here, it is assumed that the priority of data distributed in MC1 is lower than the priority of data distributed in MC2 and MC3, and the priority of distribution data in MC2 and MC3 is the same. The communication device 20a uses the one with the lower traffic rate of data with high priority between the communication device 20a and the communication device 20b for transferring the distribution data of the multicast group MC3. Here, the communication device 20b is transferring MC2 distribution data, whereas the communication device 20a is not transferring high priority data. Therefore, the communication device 20a determines the communication device 20a as the rendezvous point RP3 of the multicast group MC3. Furthermore, the communication device 20a stops the transfer of data distributed by the MC1, and cancels the setting of the RP1 in the communication device 20a.

  As described above, when the maximum rate of each redundant route is exceeded, the communication device 20a determines the transfer route in order from the multicast data with the highest priority. At this time, in order to smooth the traffic rate between the plurality of redundant routes as much as possible, the communication device 20a performs communication in a route with a low traffic rate of data having the same priority as the data for which a transfer route is to be determined. The device 20 is set as the transfer destination. Further, when the multicast device 20a is requested to transfer an amount of multicast data that exceeds the sum of the maximum rates of the redundant paths, the communication device 20a stops the distribution of the data with a relatively low priority, thereby Prevent interruption of high data delivery. In other words, it can be said that the communication device 20a selects the route to be used for transfer until the total value of the traffic rate in each route reaches the maximum rate of the route in order from the data with the highest priority. For this reason, it becomes difficult for the delivery of high priority data to fail.

  In FIG. 1, for the sake of simplicity, an example in which redundancy is made using two routes is taken as an example, but the redundancy of the route is arbitrarily set according to the implementation. In addition, the number of multicast groups that distribute data using redundant paths is also arbitrary.

<Device configuration>
FIG. 2 shows an example of the configuration of the communication device 20. The communication device 20 includes a reception unit 21, a transmission unit 22, a calculation unit 23, a notification unit 24, a transfer processing unit 25, an arrangement control unit 30, and a storage unit 40. The arrangement control unit 30 includes a priority specifying unit 31, a selection unit 32, a generation unit 33, an update unit 34, and a deletion processing unit 35. Further, the storage unit 40 holds setting data 41, in-transfer data information 42, and RP setting information 43.

  The receiving unit 21 receives a packet transmitted from another communication device 20 or the transfer device 10. The transmission unit 22 transmits the packet to another communication device 20 or the transfer device 10. For example, the transmission unit 22 performs transmission processing of packets input from the notification unit 24 and the transfer processing unit 25. The calculation unit 23 calculates the traffic rate of multicast data transferred from another transfer device 10. The calculation unit 23 outputs the calculation result to the selection unit 32.

  The notification unit 24 generates notification information for notifying the communication device 20 operating as a rendezvous point to other transfer devices 10 and communication devices 20 in the network for each multicast group. For example, the notification information may be a packet addressed to the transfer apparatus 10 that operates as a BSR (Bootstrap Router) in the network. In this case, the BSR notifies the transfer device 10 and the communication device 20 in the network of the information included in the received notification information based on the PIM-SM. The transfer processing unit 25 performs a process for transferring a multicast packet that is transferred by the communication device 20. The transfer processing unit 25 transfers the processed packet to the other transfer device 10 by outputting it to the transmission unit 22.

  Among the plurality of communication devices 20 in the network, in the communication device 20 (the communication device 20a in FIG. 1) that distributes the multicast data transfer path, the priority specifying unit 31, the selection unit 32, the generation unit 33, and the update unit 34 The deletion processing unit 35 operates. On the other hand, in the communication device 20 that transfers multicast data in response to a request from the communication device 20 that distributes the transfer path, the generation unit 33 and the update unit 34 operate. However, the priority specifying unit 31, the selection unit 32, Processing in the deletion processing unit 35 is not performed.

  The priority specifying unit 31 specifies the priority for multicast data transferred from another transfer device 10. For example, when the data to be preferentially transferred is set in the setting data 41, the priority specifying unit 31 can specify the priority by referring to the setting data 41. The selection unit 32 selects a route used for multicast data transfer from redundant routes. At this time, the selection unit 32 selects a route so that a difference in traffic is reduced in each route that can be used for multicast data transfer. Further, the selection unit 32 specifies the maximum rate of each route from the setting data 41 and assigns multicast data so as not to exceed the maximum rate of each route.

  The generation unit 33 generates distribution request information for notifying the other communication device 20 of the allocated route and requesting distribution, and outputs the distribution request information to the transmission unit 22. An example of distribution request information will be described later. Furthermore, the generation unit 33 generates notification information for notifying other communication devices 20 of the transfer status and rendezvous point setting status held by the communication device 20.

  The update unit 34 changes the in-transfer data information 42 and the RP setting information 43 based on the request information and the notification information. The in-transfer data information 42 is data in which the traffic rate and the identifier of the communication device 20 performing the transfer process are associated with the multicast address of the multicast data transferred by the communication device 20. Details of the data information being transferred 42 and how to use it will be described later. The RP setting information 43 is information in which a destination multicast address is associated with a rendezvous point for each multicast data distributed in the network. The RP setting information 43 is appropriately notified by the notification unit 24 to a device operating as a BSR. Information notified from the device operating as the BSR is stored in the RP setting information 43. The deletion processing unit 35 performs processing for deleting multicast data, which cannot be transferred using any route, from the processing target.

  FIG. 3 shows an example of the hardware configuration of the communication device 20. The communication device 20 includes a processor 61, a memory 62, a bus 65, an external storage device 66, and a network connection device 69. Further, as an option, the communication device 20 may include an input device 63, an output device 64, and a medium driving device 67. The communication device 20 may be realized by a computer, for example.

  The processor 61 can be any processing circuit including a Central Processing Unit (CPU). The processor 61 operates as the calculation unit 23, the notification unit 24, the transfer processing unit 25, and the arrangement control unit 30. The processor 61 can execute a program stored in the external storage device 66, for example. The memory 62 operates as the storage unit 40 and holds setting data 41, in-transfer data information 42, and RP setting information 43. Further, the memory 62 appropriately stores data obtained by the operation of the processor 61 and data used for processing of the processor 61. The network connection device 69 is used for communication with other devices and operates as the reception unit 21 and the transmission unit 22.

  The input device 63 is realized as, for example, a button, a keyboard, or a mouse, and the output device 64 is realized as a display or the like. The bus 65 connects the processor 61, the memory 62, the input device 63, the output device 64, the external storage device 66, the medium drive device 67, and the network connection device 69 so that data can be exchanged between them. The external storage device 66 stores programs, data, and the like, and provides the stored information to the processor 61 and the like as appropriate. The medium driving device 67 can output the data of the memory 62 and the external storage device 66 to the portable storage medium 68, and can read programs, data, and the like from the portable storage medium 68. Here, the portable storage medium 68 is an arbitrary portable storage medium including a floppy disk, a Magneto-Optical (MO) disk, a Compact Disc Recordable (CD-R), and a Digital Versatile Disk Recordable (DVD-R). It can be a medium.

<Communication method>
FIG. 4 shows an example of a network. In the example of FIG. 4, multicast groups MC1 to MC4 are formed in the network. The network shown in FIG. 4 includes transfer apparatuses 10a to 10e, and the maximum rate on the path from the transfer apparatus 10b to the transfer apparatus 10e is 1000 Mbps. Further, between the transfer device 10a and the transfer device 10b, there are a route passing through the communication device 20a and a route passing through the communication device 20b, and the maximum rate of either route is 100 Mbps. In the network of FIG. 4, the transfer device 10 c operates as a BSR, and notifies each transfer device 10 and the communication device 20 of the rendezvous point setting status. Hereinafter, the case where the transfer route of the data distributed by the multicast groups MC1 to MC4 is distributed in the network shown in FIG. 4 will be described as an example. It is assumed that the traffic rate of data distributed in each multicast group is as shown in the table in FIG.

  Here, in order to easily distinguish the communication devices 20, the communication device 20 that distributes multicast data transfer paths may be referred to as a “master-side communication device 20”. On the other hand, the communication device 20 that performs the transfer process according to the allocation notified from the master-side communication device 20 may be referred to as a “slave-side communication device 20”. Furthermore, in order to make it easy to understand which operation is performed by the communication device 20a or the communication device 20b, it is included in the number of the communication device 20 performing the processing after the part number in the communication device 20. Write the alphabet. For example, the calculation unit 23a is included in the communication device 20a.

[Processing before congestion occurs]
FIG. 5 shows an example of the setting data 41. The setting data 41 is set as information common to the communication device 20a and the communication device 20b. In the setting data 41, the selection unit 32a of the communication device 20a has the IP address of the master device assigned to the communication device 20a. Therefore, when the communication device 20a distributes the multicast data transfer path, judge. On the other hand, since the IP address of the slave device is the IP address assigned to the communication device 20b in the setting data 41, the communication device 20b transfers the data addressed to the address notified from the master communication device 20a. .

  The RP distribution multicast address information included in the setting data 41 represents an address that is a destination of multicast data distributed using a redundant route. here. The RP distribution multicast address may be specified as a range of addresses including a plurality of addresses. In the example of FIG. 5, since the RP distribution multicast address information is 239.0.0.0/24, the address group whose upper 24 bits are 239.0.0 is transferred by the communication device 20a or the communication device 20b. It is set as the target of. The preferential transfer data is a multicast IP address used for transmission of preferentially transferred data. In the example of FIG. 5, data destined for either 239.0.0.100 or 239.0.0.101 is preferentially transferred. The maximum rate represents the maximum rate in the path including each of the communication device 20a and the communication device 20b.

  (1) When the communication device 20a and the communication device 20b are initialized, the in-transfer data information 42 and the RP setting information 43 are initialized in any communication device 20. Thereafter, the update unit 34a of the communication device 20a, which is the master device, acquires the address set in the RP distribution multicast address information of the setting data 41 as the destination address of the data to be transferred. The update unit 34a generates the RP setting information 43a using the acquired information. As shown in FIG. 6A, the RP setting information 43 holds difference information, a multicast address, a distribution status, and identification information of the communication device 20 set as a rendezvous point. Here, the difference information indicates whether the setting of the rendezvous point has been changed, and is set to “update” in the changed entry. The distribution status represents whether the communication device 20 set as the rendezvous point is transferring distribution data whose destination is the multicast address in the entry. The example in FIG. 6A shows that a rendezvous point is newly set in the communication device 20a for an address specified by 239.0.0.0/24. The notification unit 24a generates notification information including the contents of the RP setting information 43a, and transmits the notification information to the transfer device 10c via the transmission unit 22a. Note that the notification unit 24 stores in advance that the transfer device 10c is a BSR and holds the address of the transfer device 10c.

  (2) Upon receiving the notification information generated by the communication device 20a, the transfer device 10c rendezvous data destined for the multicast address of 239.0.0.0/24 to the transfer device 10 and the communication device 20 in the network. Notify that the point is the communication device 20a. By this processing, the data represented by 239.0.0.0/24 is transferred via the communication device 20a.

  (3) Next, it is assumed that the node D1 transmits data addressed to the multicast group MC1 to the transfer device 10a. Here, it is assumed that the multicast address assigned to MC1 is 239.0.0.1/32. The transfer device 10a transfers the distribution data of MC1 transmitted from the node D1 to the communication device 20a.

  (4) The receiving unit 21a of the communication device 20a outputs the received data to the transfer processing unit 25a. The transfer processing unit 25a requests the selection unit 32a to set a route because 239.0.0.1/32 that is the destination of the input data is not recorded in the data information being transferred 42a. Furthermore, the transfer processing unit 25a requests the calculation unit 23a to calculate the traffic rate of data addressed to the multicast group MC1. The calculation unit 23a calculates the traffic rate and outputs the obtained result to the selection unit 32a. Here, it is assumed that the traffic rate of data addressed to the multicast group MC1 is calculated to be 10 Mbps.

  The selection unit 32a calculates the total traffic rate for the route including the communication device 20a and the route including the communication device 20b using the data information 42a being transferred, and then transfers the route having the smaller total value. Select as a route. Here, neither of the communication devices 20a and 20b transfers multicast data. For this reason, the selection unit 32a selects the route through the communication device 20a as the data transfer route of MC1.

  (5) The selection unit 32a records the selection result in the in-transfer data information 42a as shown in FIG. 6B. The in-transfer data information 42 includes difference information, a multicast address designated as a destination of data to be transferred, a traffic rate, and identification information of the communication device 20 that performs the transfer process. In the example of FIG. 6B, the multicast group corresponding to the multicast address is described in order to make it easy to identify the multicast group in the description. 42 may not be included. Here, the difference information is used as a flag indicating whether the rendezvous point is newly set. The traffic rate is a traffic rate of distribution data destined for the associated multicast address.

  By changing the in-transfer data information 42a as shown in FIG. 6B, the rendezvous point for the multicast data destined for 239.0.0.1/32 is set in the communication device 20a. Therefore, the transfer processing unit 25a performs processing for transferring the distribution data of the multicast group MC1 to the transfer device 10b and transfers the data via the transmission unit 22a.

  Further, the generation unit 33a generates notification information for notifying the communication device 20b of the information of the data information 42a being transferred, and transmits the notification information to the communication device 20b via the transmission unit 22a. By this processing, the communication device 20b recognizes that the rendezvous point for the multicast data destined for 239.0.0.1/32 is the communication device 20a.

  Note that the multicast address that is the destination of the data addressed to MC1 is set to be transferred via a route via the communication device 20a in the RP setting information 43 shown in FIG. 6A. / 24. For this reason, the content of the RP setting information 43a is not changed, and the setting of the rendezvous point in the network is not changed.

  (6) It is assumed that the node D2 transmits data addressed to the multicast group MC2 to the transfer device 10a. Here, it is assumed that the multicast address assigned to MC2 is 239.0.0.2/32. Since the address addressed to MC2 is included in 239.0.0.0/24, transfer device 10a transfers the distribution data of MC2 transmitted from node D2 to communication device 20a.

  (7) The selection unit 32a of the communication device 20a is requested to select a transfer path from the transfer processing unit 25a by the same process as in the procedure (4). Further, as in the procedure (4), the calculation unit 23a obtains the traffic rate of the data for which the transfer path is determined and outputs it to the selection unit 32a.

  The selection unit 32a selects a route having a smaller total traffic rate as a transfer route. For this reason, the selection unit 32a calculates the total value of the traffic rate for each of the route including the communication device 20a and the route including the communication device 20b using the data information 42a being transferred. Here, the communication device 20a is transferring 10 Mbps data, whereas the communication device 20b is not transferring multicast data. For this reason, the selection unit 32a selects a route passing through the communication device 20b as a transfer route for data distributed by the MC2.

  The selection unit 32a notifies the generation unit 33a of the selected result and requests generation of distribution request information. The distribution request information associates the multicast address that is the destination of the data for which the route has been selected with the identification information of the communication device 20 included in the data route. FIG. 6C is an example of distribution request information used when the communication device 20a requests the communication device 20b to transfer data distributed by MC2. In the example of FIG. 6C, the distribution request information includes difference information and request contents in addition to the multicast address that is the destination of the data for which the route is selected and the identification information of the communication device 20 that is the request destination. The difference information is used as a flag indicating whether the information is a new setting request. The communication device 20a periodically transmits distribution request information to the communication device 20b in order to match the transfer status between the communication device 20a and the communication device 20b. Therefore, if a new transfer is requested, the difference information is set to “update”. The request content indicates whether transfer start or transfer end is requested. The generation unit 33a transmits the distribution request information illustrated in FIG. 6C to the communication device 20b via the transmission unit 22a.

  (8) Upon receiving the distribution request information, the receiving unit 21b of the communication device 20b outputs the distribution request information to the updating unit 34b. The update unit 34 b records information included in the input distribution request information in the RP setting information 43. For this reason, the RP setting information 43b held by the communication device 20b is updated as shown in FIG. The notification unit 24b generates notification information including the content of the RP setting information 43b, and transmits the notification information to the transfer device 10c via the transmission unit 22b. Using the notification information received from the communication device 20b, the transfer device 10c notifies the transfer device 10 and the communication device 20 in the network that the rendezvous point of the multicast data addressed to MC2 is the communication device 20b. For this reason, in the procedure (8) and subsequent steps, the transfer device 10a transfers multicast data addressed to MC2 to the communication device 20b.

  (9) Since the rendezvous point of the multicast data addressed to MC2 is set in the communication device 20b, the update unit 34b of the communication device 20b records in the in-transfer data information 42b that the data distributed by the MC2 is distributed. . For this reason, the in-transfer data information 42b is updated as shown in FIG. The generation unit 33b generates notification information for notifying the communication device 20a of the contents of the data information 42b being transferred, and outputs the notification information to the transmission unit 22b. The transmission unit 22b transmits the input notification information to the communication device 20a.

  (10) The receiving unit 21a of the communication device 20a outputs the notification information to the updating unit 34a. The update unit 34a extracts information whose difference information is set to “update” from the notification information and adds it to the data information 42a being transferred. For this reason, the in-transfer data information 42a is updated as shown in FIGS. 6B to 7A.

  (11) Next, it is assumed that the node D3 transmits data addressed to the multicast group MC3 to the transfer device 10a. Here, it is assumed that the multicast address assigned to MC3 is 239.0.0.3/32. Since the address addressed to MC3 is included in 239.0.0.0/24, transfer device 10a transfers the distribution data of MC3 transmitted from node D3 to communication device 20a.

  (12) Similar to the procedure (4), the calculation unit 23a of the communication device 20a obtains the traffic rate of the data for which the transfer path is determined and outputs it to the selection unit 32a. Here, it is assumed that the traffic rate of data distributed by MC3 is 50 Mbps.

  The selection unit 32a selects each of a route including the communication device 20a and a route including the communication device 20b in order to select a route having a smaller total traffic rate of data being transferred as a transfer route of newly distributed data. Calculate the total traffic rate for. As shown in the in-transfer data information 42a in FIG. 7A, the communication device 20a is transferring 10 Mbps data, while the communication device 20b is transferring 40 Mbps data. Therefore, the selection unit 32a selects a route passing through the communication device 20a as a transfer route of data distributed by the MC3.

  The selection unit 32a records the selection result in the in-transfer data information 42a as shown in FIG. 7B. By changing the in-transfer data information 42a as shown in FIG. 7B, a rendezvous point for multicast data destined for 239.0.0.3/32 is set in the communication device 20a. Therefore, the transfer processing unit 25a performs processing for transferring the distribution data of the multicast group MC3 to the transfer device 10b, and transfers the data via the transmission unit 22a.

  (13) The generation unit 33a generates notification information for notifying the communication device 20b of the information of the data information 42a being transferred, and transmits the notification information to the communication device 20b. At this time, the generation unit 33a also generates distribution request information for the multicast data for which the communication device 20b performs the transfer process among the information included in the data information 42a being transferred. As shown in FIG. 7 (b), the information related to the data to be transferred by the communication device 20b is not information updated after the information of the data information being transferred 42 is finally synchronized with the communication device 20b. Therefore, as illustrated in FIG. 7C, the generation unit 33a transmits distribution request information in which “update” is not set in the difference information to the communication device 20b.

  (14) Thereafter, the notification unit 24a generates notification information including the contents of the RP setting information 43a, and transmits the notification information to the transfer device 10c via the transmission unit 22a. Note that the multicast address that is the destination of the data destined for MC3 is set to be transferred to the RP setting information 43a in the route via the communication device 20a in the procedure (2) 239.0.0.0/24. Included in For this reason, the content of the RP setting information 43a is not changed from the step (8), and the rendezvous point setting also remains in the state of the procedure (8).

[Transfer processing for transfer processing target]
Next, the processing when the sum of the maximum rates of the redundant routes is equal to or greater than the total value of the traffic rates of the multicast data being distributed will be described.

  (21) After the processing of the procedure (14), it is assumed that the node D4 transmits data addressed to the multicast group MC4 to the transfer device 10a. Here, it is assumed that the multicast address assigned to MC4 is 239.0.0.4/32. The transfer device 10a transfers distribution data addressed to MC4 to the communication device 20a.

  (22) The calculation unit 23a of the communication device 20a calculates the traffic rate of the data distributed to the MC 4, and outputs the calculation result to the selection unit 32a. Here, it is assumed that the traffic rate of data distributed to MC4 is 70 Mbps. Similar to the procedure (4) and the like, the selection unit 32a tries to select a route having a smaller total traffic rate of data being transferred as a transfer route. As shown in FIG. 7B, the total traffic rate in the route including the communication device 20a is 60 Mbps, and the total value in the route including the communication device 20b is 40 Mbps. FIG. 8A shows the data transfer amount in each route when the transfer route for the distribution data of MC4 is assigned to a route having a smaller total traffic rate. When MC4 is allocated to the path including the communication apparatus 20b, a traffic rate of 110 Mbps is allocated to the path including the communication apparatus 20b. Then, data transfer exceeding the maximum rate (100 Mbps) is allocated to the route including the communication device 20b, and congestion occurs.

  (23) If new multicast data transfer is allocated to a route with a smaller total traffic rate of data being transferred and the maximum rate of the route is exceeded, the selection unit 32 changes the data transferred between the routes. It is determined whether congestion can be eliminated by doing. When the traffic rate of certain data allocated to the route whose total value exceeds the maximum rate is lower than the traffic rate of data allocated to the route whose total value is less than or equal to the maximum rate, the selection unit 32 transfers the data. Swap the target. As an example, the selection unit 32 may select a traffic rate between data having a minimum traffic rate among transfer targets of a route whose total value exceeds the maximum rate and data having a minimum traffic rate among transfer targets of the other route. Can be compared. In this case, if the traffic rate of the data to be transferred on the route whose total value exceeds the maximum rate is lower, the selection unit 32 replaces both.

  For example, in the case of FIG. 8A, the selection unit 32a assumes that the distribution data of MC4 is allocated to the route including the communication device 20b, and then, for each multicast address of the data that each communication device 20 performs transfer processing. And specify the traffic rate. The data with the minimum traffic rate is data transferred at 10 Mbps to 239.0.0.1 in the communication device 20a, and data transferred at 40 Mbps to 239.0.0.2 in the communication device 20b. is there. Therefore, the selection unit 32a allocates the transfer of 10 Mbps data addressed to 239.0.0.1 to the communication device 20b, and allocates the transfer of 40 Mbps data addressed to 239.0.0.2 to the communication device 20a. The processing amount in each communication device 20 is calculated. Then, as shown in FIG. 8B, the total value of the transfer rates is 100 Mbps or less, which is the maximum rate of the path, in any of the communication apparatuses 20.

  (24) The selection unit 32a notifies the generation unit 33a that data to be transferred is allocated along the arrangement determined in the procedure (23). The generation unit 33a generates distribution request information for assigning a route as notified from the selection unit 32a. In order to place data as shown in FIG. 8B, the communication device 20a transfers the multicast address 239.0.0.1 and the data addressed to 239.0.0.4 to the communication device 20b. And end of transfer of data addressed to 239.0.0.2. Therefore, the generation unit 33a generates distribution request information illustrated in FIG. The generation unit 33a transmits the generated distribution request information to the communication device 20b via the transmission unit 22a.

(25) Upon receiving the distribution request information, the receiving unit 21b of the communication device 20b outputs the distribution request information to the updating unit 34b. Using the information included in the input distribution request information, the update unit 34b updates the RP setting information 43b as shown in FIGS. 9B to 9C. The notification unit 24b generates notification information including the content of the RP setting information 43b, and transmits the notification information to the transfer device 10c via the transmission unit 22b. Using the notification information received from the communication device 20b, the transfer device 10c notifies the transfer device 10 and the communication device 20 in the network that the rendezvous point of the multicast data addressed to MC1 and MC4 is the communication device 20b. . Furthermore, the transfer device 10c notifies the transfer device 10 and the communication device 20 in the network that the rendezvous point of the multicast data addressed to MC2 has been changed to the communication device 20a.
Therefore, in the procedure (25) and subsequent steps, the transfer device 10a transfers the multicast data distributed to MC1 or MC4 to the communication device 20b, and transfers the multicast data addressed to MC2 or MC3 to the communication device 20a.

  (26) Since the rendezvous point of the multicast data addressed to MC1 and MC4 is set in the communication device 20b, the update unit 34b of the communication device 20b updates the data-in-transfer data information 42b as shown in FIG. 9 (d). To do. Further, the generation unit 33b generates notification information for notifying the communication device 20a of the contents of the data information 42b being transferred, and outputs the notification information to the transmission unit 22b. The transmission unit 22b transmits the input notification information to the communication device 20a.

  (27) The receiving unit 21a of the communication device 20a outputs the notification information to the updating unit 34a. The update unit 34a extracts information whose difference information is set to “update” from the notification information and adds it to the data information 42a being transferred. For this reason, the in-transfer data information 42a is updated as shown in FIG.

[Processing when congestion occurs]
Next, processing when congestion occurs will be described. When the sum of the maximum rates of the redundant paths is less than the total traffic rate of the multicast data being distributed, congestion occurs and the following processing is performed. In addition, the total of the maximum rates of the redundant routes is equal to or greater than the total value of the traffic rate of the multicast data being distributed, but the total traffic rate of each route cannot be reduced below the maximum rate by exchanging routes Also in this case, the following processing is performed.

  (31) After the processing of the procedure (27), it is assumed that the nodes included in the multicast group MC5 start distributing data. Here, it is assumed that 239.0.0.100/32 is assigned to the multicast group MC5, and is to be preferentially transferred. Furthermore, the data addressed to the multicast group MC5 is distributed from the node connected to the transfer device 10a to the node connected to the transfer device 10e. The transfer device 10a transfers distribution data addressed to 239.0.0.100/32 to the communication device 20a.

  (32) The calculation unit 23a of the communication device 20a calculates the traffic rate of the data addressed to MC5 and outputs the traffic rate to the selection unit 32a. Here, it is assumed that the traffic rate of data addressed to MC5 is 50 Mbps.

  Similar to the procedure (4), the selection unit 32a tries to select the route having the smaller total traffic rate of the data being transferred as the transfer route of the data addressed to the MC5. As shown in FIG. 9 (e), since the communication device 20a transfers the data of MC2 and MC3, the total value of the traffic rate is 90 Mbps. On the other hand, since the communication device 20b transfers the data of MC1 and MC4, the total value of the traffic rate is 80 Mbps. For this reason, the route including the communication device 20b has a smaller total traffic rate of data being transferred than the route including the communication device 20a.

  FIG. 10 (a) shows the total value of the traffic rate in each route when the distribution data transfer of MC5 is assigned to the communication device 20b. Currently, since the communication device 20b transfers 80 Mbps data, further allocation of MC5 data results in allocation of data transfer exceeding the maximum rate of the route to the communication device 20b, and the route including the communication device 20b. Causes congestion.

  (33) Therefore, the selection unit 32a assumes that the transfer of data newly started to be distributed is assigned to the path with the smaller total traffic rate of the data being transferred, and then assigns the data to each communication device 20. The transfer priority is determined for each data. The priority specifying unit 31a specifies a priority for each multicast data transferred from the transfer device 10a, and notifies the selection unit 32a of the obtained priority. Since the data addressed to 239.0.0.100/32 is recorded as high-priority data in the setting data 41 (FIG. 5), the priority specifying unit 31a has high priority for the data addressed to MC5. This is notified to the selection unit 32a. Furthermore, since none of the data addressed to MC1 to MC4 is recorded as data to be preferentially transferred to the setting data 41, the priority level specifying unit 31a indicates that the priority level of the data addressed to MC1 to MC4 is low. Notify the selection unit 32a.

  The selection unit 32a sets the priority of data transfer so that the higher the priority, the higher the priority, and the higher the priority among the data with the same priority, the lower the traffic rate. decide. As a result, the transfer priority is determined as shown in FIG. For example, since the data addressed to 239.0.0.100/32 has a high priority, the priority of the data addressed to 239.0.0.100/32 is allocated to the communication device 20b by the selection unit 32a. To first place. Since all the remaining data allocated to the communication device 20b has a low priority, the selection unit 32a determines the priority order in ascending order of the traffic rate. For this reason, the priority of the data transferred by the communication device 20b is the second place for the data destined for 239.0.0.1 and the third place for the data destined for 239.0.0.4. Since the selection unit 32a performs the same processing on the communication device 20a, the priority of transfer in the communication device 20a is the data addressed to 239.0.0.2 and the data addressed to 239.0.0.3. Data is second.

  (34) The selection unit 32a stops the transfer of the data with the lowest priority among the data included in the route in which congestion occurs due to the transfer of the newly started distribution of data. In the case shown in FIG. 10B, it is predicted that congestion will occur in the route including the communication device 20b by transferring data addressed to the multicast group MC5. Therefore, the selection unit 32a determines to stop the transfer of data addressed to 239.0.0.4 which is the lowest priority data among the data allocated to the communication device 20b. Further, the selection unit 32a determines to transfer data addressed to 239.0.0.100 via the communication device 20b. The selection unit 32a notifies the determined allocation to the generation unit 33a and the deletion processing unit 35a. Then, the generation unit 33a requests the communication device 20b to start the transfer of data addressed to 239.0.0.100 and stop the transfer of data addressed to 239.0.0.4. The distribution request information shown in (a) is generated and transmitted to the communication device 20b via the transmission unit 22a.

  (35) Upon receiving the distribution request information, the receiving unit 21b of the communication device 20b outputs the distribution request information to the updating unit 34b. The update unit 34b updates the RP setting information 43b as shown in FIG. 11B using information included in the input distribution request information. The notification unit 24b transmits notification information including the contents of the RP setting information 43b to the transfer device 10c via the transmission unit 22b. Using the notification information received from the communication device 20b, the transfer device 10c notifies the transfer device 10 and the communication device 20 in the network that the rendezvous point of the multicast data addressed to MC1 and MC5 is the communication device 20b. . By this process, both the communication device 20a and the communication device 20b hold the RP setting information 43 shown in FIG. Therefore, in the subsequent processing, the transfer device 10a transfers multicast data addressed to an address corresponding to 239.0.0.0/24 other than MC1 and MC5 to the communication device 20a. In addition, the transfer device 10a transfers the multicast data distributed to MC1 or MC5 to the communication device 20b.

  (36) By the way, when the transfer is canceled due to the occurrence of congestion, the transfer to the master side communication device 20 will also generate congestion for the data whose transfer has been stopped. For this reason, the deletion processing unit 35 included in the master communication device 20 deletes the rendezvous point setting for the data whose transfer has been canceled.

  In the example described with reference to FIG. 10B, the selection unit 32a has decided to stop the transfer of data addressed to 239.0.0.4. By the processing in the procedure (34), multicast data in which an address corresponding to 239.0.0.0/24 is designated other than MC1 and MC5 is transferred to the communication device 20a. Then, in the path between the transfer device 10a and the communication device 20a, in addition to the data of MC2 and MC3, it is also used for the transfer of data of MC5, so there is congestion between the transfer device 10a and the communication device 20a. Will occur. Therefore, the deletion processing unit 35a deletes data addressed to 239.0.0.4 from the transfer target in the communication device 20a. Therefore, the deletion processing unit 35a changes the contents of the RP setting information 43a as shown in FIG. 12 (a) to FIG. 12 (b).

(37) The notification unit 24a transmits the notification information including the contents of the RP setting information 43a (FIG. 12B) to the transfer device 10c via the transmission unit 22a. The transfer apparatus 10c notifies the notification information received from the communication apparatus 20a to the transfer apparatus 10 and the communication apparatus 20 in the network.
By this processing, neither the communication device 20a nor the communication device 20b is a rendezvous point for data addressed to MC4 (data addressed to 239.0.0.4/32). In addition, the rendezvous point of the data addressed to the MC 4 is not set in the other transfer apparatuses 10. Then, since the transfer device 10a does not transfer the multicast data addressed to MC4 to either the communication device 20a or the communication device 20b, congestion in the network does not occur. For this reason, the transfer status in each communication device 20 is as shown in FIG.

  (38) It is assumed that the node included in the multicast group MC6 starts data distribution after the process of the procedure (37). Here, it is assumed that 239.0.0.101/32 is assigned to the multicast group MC6 and is to be preferentially transferred. Further, data destined for the multicast group MC6 is also distributed from the node connected to the transfer device 10a to the node connected to the transfer device 10e. The transfer device 10a transfers distribution data addressed to 239.0.0.101/32 to the communication device 20a.

  (39) It is assumed that the calculation unit 23a of the communication device 20a calculates that the traffic rate of data distributed to the MC 6 is 45 Mbps. The selection unit 32a determines whether the data distributed to the MC 6 can be transferred through the route with the smaller total traffic of the data being transferred, as in the procedure (32). As shown in FIG. 10C, the total value of the traffic of the route including the communication device 20a is 90 Mbps, the total value of the traffic of the route including the communication device 20b is 60 Mbps, and the maximum rate of any route is 100 Mbps. . For this reason, the maximum rate is exceeded regardless of which route is used. Therefore, the selection unit 32a determines whether congestion can be eliminated by changing the data allocation. When the distribution data of MC6 is allocated to the route including the communication device 20b, congestion occurs in the route including the communication device 20b. Here, the minimum value of the traffic rate of data allocated to the communication device 20b is 10 Mbps destined for MC1, while the minimum value of the traffic rate of data allocated to the communication device 20a is 40 Mbps destined for MC2. For this reason, the selection unit 32a determines that the congestion cannot be resolved even by changing the data allocation, and determines to select the transfer target using the priority.

  (40) It is assumed that the priority specifying unit 31a specifies that the data distributed to the MC 6 is data to be preferentially transferred and notifies the selection unit 32a. Therefore, the selection unit 32a allocates the transfer of newly started distribution of data to the path with the smaller total traffic rate used for transferring high priority data, and then sets each communication device. The priority for the transfer of the data allocated to 20 is determined.

  In this example, as shown in FIG. 10C, the communication device 20a does not transfer high priority data. On the other hand, since the communication device 20b transfers the data of MC5 having a high priority, the total traffic rate for the high priority data in the communication device 20b is 50 Mbps. Therefore, the selection unit 32a allocates MC6 data to the communication device 20a, and determines the transfer priority for the route allocated to the communication device 20a. The method for determining the priority order is the same as in the procedure (33). Therefore, when the data of MC6 is allocated to the communication device 20a, the transfer priority in the communication device 20a is changed from FIG. 13A to FIG. 13B.

  (41) As illustrated in FIG. 13B, the selection unit 32a obtains a total value of traffic rates when the MC 6 is allocated to the communication device 20a. When allocation is performed as shown in FIG. 13B, when all of the allocated data is to be transferred, transfer of data exceeding the maximum rate of the path is allocated to the path including the communication device 20a. Congestion occurs. Therefore, the selection unit 32a stops the transfer of data addressed to 239.0.0.3, which is the lowest priority data, and transmits data addressed to 239.0.0.101 via the communication device 20a. And decide to transfer. The selection unit 32a notifies the deletion processing unit 35a of the determined allocation.

  (42) The deletion processing unit 35a updates the RP setting information 43a as shown in FIG. 13C based on the information input from the selection unit 32a. The notification unit 24a transmits notification information including the content of the RP setting information 43a to the transfer device 10c via the transmission unit 22a. The transfer apparatus 10c notifies the notification information received from the communication apparatus 20a to the transfer apparatus 10 and the communication apparatus 20 in the network. Therefore, neither the communication device 20a nor the communication device 20b is a rendezvous point for data addressed to MC3 (data addressed to 239.0.0.3/32). Since the rendezvous point of the data addressed to MC3 is not set in the other transfer devices 10 as well, it is possible to prevent the occurrence of congestion due to the multicast data addressed to MC3 being transferred from the transfer device 10a to the communication device 20a or the communication device 20b. At this time, the transfer device 10a may discard multicast data in which no rendezvous point is set in either the communication device 20a or the communication device 20b.

  In the processing using the priority described above, the communication device 20 on the master side performs processing for selecting the currently assigned route as the route to be used for transfer in order from the route with the highest priority. It can be said that the rate goes until the maximum rate of the route is reached. For this reason, the higher the priority order, the easier it is to assign the transfer path, and the more difficult the transfer is to fail.

  The update unit 34a can also periodically check the data information 42a being transferred to determine whether the transfer of data with high priority has been completed. When the transfer of data with high priority is completed, the updating unit 34a can reset the address range included in the setting data 41 as a rendezvous point for the communication device 20 on the master side. For example, when the setting data 41 illustrated in FIG. 5 is used, the update unit 34a determines whether the transfer of data addressed to 239.0.0.100 and 239.0.0.101 has been completed. The determination is made using the data information 42a. When the transfer of data addressed to 239.0.0.100 and 239.0.0.101 has been completed, the updating unit 34a distributes 239.0.0.0/24 to the RP setting information 43a. Reset as target. For this reason, it is possible to resume the transfer of the multicast data once the transfer of data is stopped after the transfer of the high priority data.

  FIG. 14 is a flowchart illustrating an example of processing of the communication device. FIG. 14 shows an example of processing when the master communication device 20 receives multicast data. When the master communication device 20 receives the multicast data, the selection unit 32 specifies the multicast address that is the destination of the data, and the calculation unit 23 calculates the traffic rate A used for the multicast data transfer (step S1). . The selection unit 32 refers to the in-transfer data information 42 and acquires information on the multicast data being transferred (step S2). The selection unit 32 determines whether the received data is multicast data that is already being transferred (step S3). At this time, the selection unit 32 searches the data information being transferred 42 using the acquired multicast address as a key, and determines whether there is a matching entry.

  If an entry that matches the acquired multicast address is not obtained from the in-transfer data information 42, the selection unit 32 determines that new multicast data has been received ("new" in step S3). The selector 32 obtains the total value of the traffic rates of the data being transferred for each of the two redundant routes, and further acquires the maximum rate of the route from the setting data 41 (step S4). Here, it is assumed that the total value in the route having the larger total traffic rate of the data being transferred is X, and the total value in the route having the smaller total traffic rate of the data being transferred is Y. Also, let Z be the maximum rate of the route. The selection unit 32 adds a value obtained by adding the traffic rate (A) of newly distributed multicast data to the lower value (Y) of the total traffic rate of data being transferred, and the maximum rate of the route (Z) are compared (step S5).

  When the sum of the total value Y and the traffic rate A does not exceed the maximum rate of the route (Z ≧ Y + A), the selection unit 32 newly distributes the route with the smaller total value of the traffic rate of the data being transferred. The assigned data is allocated (Yes in step S5, step S6). The updating unit 34 updates the information of the data information 42 being transferred (Step S10). Further, the generation unit 33 and the notification unit 24 transmit and receive a control signal for sharing the contents of the data information being transferred 42 and the RP setting information 43 between the communication device 20 on the master side and the communication device 20 on the slave side ( Step S11).

  On the other hand, when the sum of the total value Y and the traffic rate A exceeds the maximum route rate (Z <Y + A) in step S5, the selection unit 32 determines that the total traffic rate of the transferred data is two routes. To determine whether it can be transferred. That is, the selection unit 32 determines whether A + X + Y> 2Z is satisfied (step S7). When the sum of the traffic rates does not exceed the total value of the maximum rate of the route (A + X + Y is 2Z or less), the selection unit 32 attempts to avoid congestion by changing the allocation of transfer data to each communication device 20 ( Yes in step S7, step S8). Then, the process of step S11 is performed. When the sum of the transferred data traffic rates exceeds the sum of the maximum rates of the paths (A + X + Y exceeds 2Z), the selection unit 32 transfers the data to be transferred so that data with higher priority is more easily transferred. (No in step S7, step S9). Then, the process of step S11 is performed. If it is determined in step S3 that the selection unit 32 has received the multicast data being transferred, the processes in steps S10 and S11 are performed, and the transfer process is continued.

  FIG. 15 is a flowchart illustrating an example of processing for changing data allocation. FIG. 15 is a flowchart illustrating an example of processing in step S8 of FIG. The selection unit 32 of the master side communication device 20 refers to the data-in-transfer information 42 and sorts the entries in the data-in-transfer information 42 for the data being transferred for each communication device 20 in ascending order of traffic rate. (Step S21). The selection unit 32 allocates transfer of additional multicast data to a path including the communication device 20 having a smaller total traffic rate during transfer (step S22). The selection unit 32 determines whether the congestion can be reduced by replacing the data with the minimum traffic rate on the route to which the additional data is allocated with the data with the minimum traffic rate on the other route (step S23). If it determines with Yes by step S23, the selection part 32 will replace allocation of the data of the minimum traffic rate between the communication apparatuses 20 (step S24). If it determines with No by step S23, the selection part 32 will perform the process which selects the transfer object using the priority of step S9 (No in step S23). The selection unit 32 determines whether the excess of the maximum rate of the route has been eliminated (step S25). If the excess of the maximum rate of the route has not been resolved, the selection unit 32 repeats the processing after step S23 (No in step S25). When the excess of the maximum rate of the route is resolved, the master side communication device 20 transmits the distribution request information to the slave side communication device 20. The communication device 20 on the slave side updates the RP setting information 43 with the distribution request information (step S26).

  FIG. 16 is a flowchart illustrating an example of a data allocation method using priority. FIG. 16 is a flowchart illustrating an example of processing in step S9 of FIG. The selection unit 32 of the communication device 20 on the master side determines the priority order of the assigned transfer data for each communication device 20. Here, the priority is determined such that the higher the priority is, the higher the priority is. Further, between the data with the same priority, the priority is determined so that the priority is higher as the traffic rate is lower (step S31). Note that when the priority is high, the ranking number is a small value. The selection unit 32 allocates transfer of new multicast data to a path including the communication device 20 with a smaller total traffic rate of data with high priority (step S32). For a route in which the total traffic rate of the allocated data exceeds the maximum rate of the route, the selection unit 32 deletes the data with the lowest priority from the transfer target (step S33). Thereafter, the selection unit 32 determines whether or not the excess of the maximum rate of the route has been eliminated (step S34). If the excess of the maximum rate of the route has not been resolved, the selection unit 32 repeats the processing after step S33 (No in step S34). When the excess of the maximum rate of the route is resolved, the master side communication device 20 transmits the distribution request information to the slave side communication device 20. The communication device 20 on the slave side updates the RP setting information 43 with the distribution request information (Step S35).

  FIG. 17 is a flowchart for explaining an example of processing when distribution request information is received. FIG. 17 shows an example of the operation when the communication device 20 on the slave side receives the distribution request information. When receiving the distribution request information, the updating unit 34 included in the slave communication device 20 refers to the information in the RP setting information 43 (step S41). The update unit 34 determines whether or not the RP setting information 43 set in the slave communication device 20 is updated based on the distribution request information (step S42). When the RP setting information 43 is updated, it is determined whether data distribution or transfer stop is requested (Yes in step S42, step S43). When data distribution is requested, the updating unit 34 adds rendezvous point information to the RP setting information 43 ("distribution" in step S43, step S44). On the other hand, when the transfer stop is requested, the updating unit 34 deletes the information of the specified rendezvous point from the RP setting information 43 (“delete” in step S43, step S45). When the RP setting information 43 is updated using the distribution request information, the update unit 34 deletes the distribution request information and ends the process (step S46).

  As described above, in the network to which the system according to the embodiment is applied, the master communication device 20 can autonomously change the allocation of data transfer between the redundant paths. For example, when congestion occurs in one of the redundant paths, the communication device 20 on the master side tries to prevent congestion by exchanging data. Also, in the case where traffic exceeding the total value of the maximum rates of the redundant paths occurs, the master communication device 20 determines the priority of data transfer and does not transfer data with low priority. So, change the rendezvous point settings. Therefore, when the system according to the embodiment is applied, even when traffic exceeding the total value of the maximum rates of the redundant paths occurs, it is possible to make it difficult to transfer data with high priority. Furthermore, since the data distribution is autonomously performed by the communication device 20, the user does not have to manually set the rendezvous point for each multicast data to be transferred using the redundant path.

  The embodiment is not limited to the above, and can be variously modified. Some examples are described below.

  Between the communication devices 20, only the updated portion of the in-transfer data information 42 and the RP setting information 43 may be transmitted / received. In this case, the generation unit 33 and the notification unit 24 extract the information related to the change of the rendezvous point setting from the in-transfer data information 42 and the RP setting information 43 and transfer the obtained information to the other transfer devices 10 and the communication devices 20. Send.

  In the above description, the communication device 20a and the communication device 20b synchronize the information in the data information being transferred 42 and the RP setting information 43 by performing IP communication using a line in the network. A dedicated line may be installed between the 20 members. When there is a dedicated line between the communication devices 20, information related to the update of the in-transfer data information 42 and the RP setting information 43 and the distribution request information are transmitted and received using the dedicated line.

  Further, in the above description, for ease of understanding, the case where one node is included in one multicast group has been described as an example, but one node may belong to a plurality of multicast groups. Furthermore, the redundancy of the path is also arbitrarily set according to the implementation. When redundancy is performed more than three times, the communication device 20 is included in each redundant route, and one of the communication devices 20 performs route allocation as the communication device 20 on the master side, The other communication device 20 operates as the slave-side communication device 20.

  In the above description, the case where the priority is set to two levels has been described as an example, but the priority may be set to three or more levels. In this case, the priority for determining the data to be transferred is set so that the higher the priority, the higher the priority. In addition, when determining the transfer target using the priority order, the communication device 20 on the master side has a smaller total value of the traffic rate of data having a higher priority than the priority of the data for which the transfer route is to be determined. Is the transfer route.

  Further, the selection unit 32 may determine that congestion has occurred when the total of traffic assigned to each route exceeds a predetermined value. Here, the predetermined value may be a maximum rate or a value smaller than the maximum rate. If the predetermined value is set to a value smaller than the maximum rate, each route can be used for purposes other than multicast data transfer.

Regarding the above-described embodiment, the following additional notes are disclosed.
(Appendix 1)
A first transfer device;
A second transfer device connected to the first transfer device via a first route or a second route;
A first communication device in the first path;
A second communication device in the second path,
The first communication device is:
In correspondence with the destination address of each data transferred from the first transfer device to the second transfer device, the priority and traffic rate of the data are specified,
The priority is relatively set so that the difference in the total value of the traffic rate between the first route and the second route is reduced, and the total value in each route does not exceed a predetermined value. Select the route to use for transfer, starting with the highest data,
Transferring the data selected as the transfer path by the first path to the second transfer apparatus;
Notifying the second communication device of the destination address of the data selected as the transfer route by the second route,
The second communication device transfers data addressed to a destination address notified from the first communication device to the second transfer device.
(Appendix 2)
The first communication device is:
Upon receiving distribution data that is data that has been distributed from the first transfer device to the second transfer device, the priority of the distribution data is specified,
Calculating a first value that is a sum of traffic rates of data having the same priority as the priority of the distribution data, the data being transferred to the second transfer device by the first communication device; ,
Calculating a second value that is a total of traffic rates of data having the same priority as the priority of the distribution data, the data being transferred to the second transfer device by the second communication device; ,
When the first value is less than or equal to the second value, the distribution data is transferred to the second transfer device, and when the second value is smaller than the first value, the second communication device The communication system according to claim 1, wherein the distribution data is requested to be transferred to the communication system.
(Appendix 3)
The first communication device is:
Calculating a third value which is a traffic rate of the distribution data;
When the second value is smaller than the first value and the sum of the second value and the third value is larger than the predetermined value in the second route, the second route First data that is assigned data is assigned to the first route, and second data that is assigned to the first route and has a traffic rate lower than that of the first data. The communication system according to appendix 2, wherein a total value of traffic rates of the second route is adjusted to be equal to or less than the predetermined value in the second route by allocating to the second route. .
(Appendix 4)
The first communication device is:
Calculating a third value which is a traffic rate of the distribution data;
When the sum of the first value, the second value, and the third value exceeds the maximum traffic rate of data that can be transferred using the first route and the second route, the distribution data Among the data that is transferred via the route that has been assigned, the data with relatively low priority is identified as the deletion target,
The communication system according to appendix 2 or 3, wherein the first transfer device deletes the data to be deleted.
(Appendix 5)
The first communication device is:
When there are a plurality of data with relatively low priority among the data transferred through the route to which the distribution data is assigned, the higher the traffic rate, the higher the priority is selected as the deletion target. The communication system according to attachment 4.
(Appendix 6)
A communication device in the first path of a network in which a first path and a second path exist between the first transfer apparatus and the second transfer apparatus,
A calculation unit that calculates a traffic rate of the data in association with a destination address of each data transferred from the first transfer device to the second transfer device;
A specifying unit that specifies the priority of the data in association with the destination address;
The priority is relatively set so that the difference in the total value of the traffic rate between the first route and the second route is reduced, and the total value in each route does not exceed a predetermined value. In order from the highest data, the selection part that selects the route used for transfer,
A generating unit that generates request information for requesting the communication device in the second path to transfer data in which the second path is selected as a transfer path;
The first path includes a transmission unit that transmits data selected as a transfer path to the second transfer apparatus, and transmits the request information to a communication apparatus in the second path. Communication device.
(Appendix 7)
The specifying unit, when receiving distribution data that is data started to be distributed from the first transfer device to the second transfer device, specifies the priority of the distribution data;
The selection unit includes:
A first value which is data transferred by the transmission unit toward the second transfer device and which is a sum of traffic rates of data having the same priority as the priority of the distribution data;
A second value that is data transferred by the communication device in the second path toward the second transfer device, and is the sum of traffic rates of data having the same priority as the priority of the distribution data Calculate
When the first value is less than or equal to the second value, the first route is selected as a route to be used for transferring the distribution data, and when the second value is smaller than the first value, The communication apparatus according to appendix 6, wherein the second path is selected as a path used for transfer of distribution data.
(Appendix 8)
The calculation unit calculates a third value that is a traffic rate of the distribution data,
The selection unit includes:
When the second value is smaller than the first value and the sum of the second value and the third value is larger than the predetermined value in the second route, the second route First data selected from the allocated data is allocated to the first path, and the second data is a data having a traffic rate lower than that of the first data and allocated to the first path. The communication according to claim 7, wherein a total value of traffic rates of the second route is adjusted to be equal to or less than the predetermined value in the second route by allocating the second route to the second route. apparatus.
(Appendix 9)
Setting information for recording an address set as a transfer destination from the first transfer device by the communication device in the first or second path;
A deletion processing unit for deleting, from the setting information, a destination address of data that is not transferred to the second transfer device from any of the first and second paths;
A notification unit that performs processing for notifying the first transfer device of the setting information;
The calculation unit calculates a third value that is a traffic rate of the distribution data,
In the selection unit, the sum of the first value, the second value, and the third value exceeds a maximum traffic rate of data that can be transferred using the first route and the second route. And, among the data transferred through the route to which the distribution data is assigned, relatively low priority data is targeted for deletion and notified to the deletion processing unit,
The deletion processing unit deletes the address of the data to be deleted from the setting information,
The communication device according to appendix 7 or 8, wherein the notification unit performs a process for notifying the first transfer device of the setting information.
(Appendix 10)
Between the first transfer device and the second transfer device, the communication device in the first route of the network in which the first route and the second route exist,
In association with the destination address of each data transferred from the first transfer device to the second transfer device, the traffic rate of the data is calculated,
Specifying the priority of the data in association with the destination address;
The priority is relatively high so that the difference in the total value of traffic rates between the first route and the second route is reduced and the total value in each route does not exceed a predetermined value. Select the route to be used for transfer, starting with the data,
Generating request information for requesting the communication device in the second route to transfer the data selected by the second route as the transfer route;
The first route transmits the data selected as the transfer route to the second transfer device, and transmits the request information to the communication device in the second route. Communication program.
(Appendix 11)
A communication device in the first path;
Upon receiving distribution data that is data that has been distributed from the first transfer device to the second transfer device, the priority of the distribution data is specified,
A first value that is data transferred by the communication device in the first path toward the second transfer device, and is a sum of traffic rates of data having the same priority as the priority of the distribution data Calculate
A second value that is data transferred by the communication device in the second path toward the second transfer device, and is the sum of traffic rates of data having the same priority as the priority of the distribution data Calculate
When the first value is less than or equal to the second value, the first route is selected as a transfer route for the distribution data, and when the second value is smaller than the first value, the second value The communication program according to appendix 10, wherein a process of selecting a path as a transfer path of the distribution data is performed.
(Appendix 12)
A communication device in the first path;
Calculating a third value which is a traffic rate of the distribution data;
When the second value is smaller than the first value and the sum of the second value and the third value is larger than the predetermined value in the second route, the second route First data selected from the allocated data is allocated to the first path, and the second data is a data having a traffic rate lower than that of the first data and allocated to the first path. Is further allocated to the second route to adjust the total traffic rate of the second route to be equal to or lower than the predetermined value in the second route. 11. The communication program according to 11.
(Appendix 13)
A communication device in the first path;
Calculating a third value which is a traffic rate of the distribution data;
When the sum of the first value, the second value, and the third value exceeds the maximum traffic rate of data that can be transferred using the first route and the second route, the distribution data Among the data that is transferred via the route that has been assigned, the data with relatively low priority is identified as the deletion target,
Deleting the data to be deleted from the target to be transferred to the second transfer device;
Additional Statement 11 or 12, further comprising: causing the communication device in the second route to transmit the request information requesting that the data to be deleted not be transferred to the second transfer device. The communication program described in 1.
(Appendix 14)
In a network in which a first path and a second path exist between the first transfer apparatus and the second transfer apparatus,
The first communication device in the first path is:
In correspondence with the destination address of each data transferred from the first transfer device to the second transfer device, the priority and traffic rate of the data are specified,
The priority is relatively set so that the difference in the total value of the traffic rate between the first route and the second route is reduced, and the total value in each route does not exceed a predetermined value. Select the route to use for transfer, starting with the highest data,
Transferring the data selected as the transfer path by the first path to the second transfer apparatus;
Notifying the second communication device included in the second route of the destination address of the data selected as the transfer route by the second route,
The second communication device transfers data addressed to a destination address notified from the first communication device to the second transfer device.

DESCRIPTION OF SYMBOLS 10 Transfer apparatus 20 Communication apparatus 21 Reception part 22 Transmission part 23 Calculation part 24 Notification part 25 Transfer process part 30 Arrangement control part 31 Priority specification part 32 Selection part 33 Generation part 34 Update part 35 Deletion process part 40 Storage part 41 Setting data 42 Data information being transferred 43 RP setting information 61 Processor 62 Memory 63 Input device 64 Output device 65 Bus 67 Medium drive device 68 Portable storage medium 69 Network connection device 70 Network

Claims (10)

A first transfer device;
A second transfer device connected to the first transfer device via a first route or a second route;
A first communication device in the first path;
A second communication device in the second path,
The first communication device is:
In correspondence with the destination address of each data transferred from the first transfer device to the second transfer device, the priority and traffic rate of the data are specified,
The priority is relatively set so that the difference in the total value of the traffic rate between the first route and the second route is reduced, and the total value in each route does not exceed a predetermined value. Select the route to use for transfer, starting with the highest data,
Transferring the data selected as the transfer path by the first path to the second transfer apparatus;
Notifying the second communication device of the destination address of the data selected as the transfer route by the second route,
The second communication device transfers data addressed to a destination address notified from the first communication device to the second transfer device. The first communication device is:
Upon receiving distribution data that is data that has been distributed from the first transfer device to the second transfer device, the priority of the distribution data is specified,
Calculating a first value that is a sum of traffic rates of data having the same priority as the priority of the distribution data, the data being transferred to the second transfer device by the first communication device; ,
Calculating a second value that is a total of traffic rates of data having the same priority as the priority of the distribution data, the data being transferred to the second transfer device by the second communication device; ,
When the first value is less than or equal to the second value, the distribution data is transferred to the second transfer device, and when the second value is smaller than the first value, the second communication device The communication system according to claim 1, wherein the transfer of the distribution data is requested. The first communication device is:
Calculating a third value which is a traffic rate of the distribution data;
When the second value is smaller than the first value and the sum of the second value and the third value is larger than the predetermined value in the second route, the second route First data that is assigned data is assigned to the first route, and second data that is assigned to the first route and has a traffic rate lower than that of the first data. The communication according to claim 2, wherein the total value of the traffic rate of the second route is adjusted to be equal to or less than the predetermined value in the second route by allocating to the second route. system. The first communication device is:
Calculating a third value which is a traffic rate of the distribution data;
When the sum of the first value, the second value, and the third value exceeds the maximum traffic rate of data that can be transferred using the first route and the second route, the distribution data Among the data that is transferred via the route that has been assigned, the data with relatively low priority is identified as the deletion target,
The communication system according to claim 2 or 3, wherein the first transfer device deletes the data to be deleted. A communication device in the first path of a network in which a first path and a second path exist between the first transfer apparatus and the second transfer apparatus,
A calculation unit that calculates a traffic rate of the data in association with a destination address of each data transferred from the first transfer device to the second transfer device;
A specifying unit that specifies the priority of the data in association with the destination address;
The priority is relatively set so that the difference in the total value of the traffic rate between the first route and the second route is reduced, and the total value in each route does not exceed a predetermined value. In order from the highest data, the selection part that selects the route used for transfer,
A generating unit that generates request information for requesting the communication device in the second path to transfer data in which the second path is selected as a transfer path;
The first path includes a transmission unit that transmits data selected as a transfer path to the second transfer apparatus, and transmits the request information to a communication apparatus in the second path. Communication device. The specifying unit, when receiving distribution data that is data started to be distributed from the first transfer device to the second transfer device, specifies the priority of the distribution data;
The selection unit includes:
A first value which is data transferred by the transmission unit toward the second transfer device and which is a sum of traffic rates of data having the same priority as the priority of the distribution data;
A second value that is data transferred by the communication device in the second path toward the second transfer device, and is the sum of traffic rates of data having the same priority as the priority of the distribution data Calculate
When the first value is less than or equal to the second value, the first route is selected as a route to be used for transferring the distribution data, and when the second value is smaller than the first value, The communication apparatus according to claim 5, wherein the second path is selected as a path used for transfer of distribution data. The calculation unit calculates a third value that is a traffic rate of the distribution data,
The selection unit includes:
When the second value is smaller than the first value and the sum of the second value and the third value is larger than the predetermined value in the second route, the second route First data selected from the allocated data is allocated to the first path, and the second data is a data having a traffic rate lower than that of the first data and allocated to the first path. The total value of the traffic rate of the second route is adjusted to be equal to or less than the predetermined value in the second route by allocating to the second route. Communication device. Setting information for recording an address set as a transfer destination from the first transfer device by the communication device in the first or second path;
A deletion processing unit for deleting, from the setting information, a destination address of data that is not transferred to the second transfer device from any of the first and second paths;
A notification unit that performs processing for notifying the first transfer device of the setting information;
The calculation unit calculates a third value that is a traffic rate of the distribution data;
In the selection unit, the sum of the first value, the second value, and the third value exceeds a maximum traffic rate of data that can be transferred using the first route and the second route. And, among the data transferred through the route to which the distribution data is allocated, the data having a relatively low priority is targeted for deletion and notified to the deletion processing unit,
The deletion processing unit deletes the address of the data to be deleted from the setting information,
The communication device according to claim 6 or 7, wherein the notification unit performs a process for notifying the first transfer device of the setting information. Between the first transfer device and the second transfer device, the communication device in the first route of the network in which the first route and the second route exist,
In association with the destination address of each data transferred from the first transfer device to the second transfer device, the traffic rate of the data is calculated,
Specifying the priority of the data in association with the destination address;
The priority is relatively high so that the difference in the total value of traffic rates between the first route and the second route is reduced and the total value in each route does not exceed a predetermined value. Select the route to be used for transfer, starting with the data,
Generating request information for requesting the communication device in the second route to transfer the data selected by the second route as the transfer route;
The first route transmits the data selected as the transfer route to the second transfer device, and transmits the request information to the communication device in the second route. Communication program. In a network in which a first path and a second path exist between the first transfer apparatus and the second transfer apparatus,
The first communication device in the first path is:
In correspondence with the destination address of each data transferred from the first transfer device to the second transfer device, the priority and traffic rate of the data are specified,
The priority is relatively set so that the difference in the total value of the traffic rate between the first route and the second route is reduced, and the total value in each route does not exceed a predetermined value. Select the route to use for transfer, starting with the highest data,
Transferring the data selected as the transfer path by the first path to the second transfer apparatus;
Notifying the second communication device included in the second route of the destination address of the data selected as the transfer route by the second route,
The second communication device transfers data addressed to a destination address notified from the first communication device to the second transfer device.

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