JP2007013808A - Multicast distribution routing setting method, reflector, and multicast distribution routing setting program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of attaining scalable IP multicast transfer as a result of the PIM protocol scalably working even under an environment wherein the scalability performance of upperstream PIM edges is deteriorated by extending the PIM protocol. <P>SOLUTION: A PIM Hello reflector remotely exchanges a Hello message with PIM routers and the other PIM Hello reflectors directly mutually to acquire a PIM adjacent relationship and stores the result to an adjacent relationship storage means, when receiving a Hello message, the PIM Hello reflector merges the received Hello message with the Hello messages stored in a message storage means, and transmits the merged Hello message to an adjacent router or an adjacent reflector acquired by referencing the adjacent relationship storage means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an IP multicast transfer technique, and in particular, a multicast distribution route setting method, a reflector and a multicast in a multicast routing protocol technique for setting an IP multicast transfer path between an IP multicast leaf router accommodating an IP multicast source and a receiver. The present invention relates to a delivery route setting program.

  The present invention also relates to a multicast distribution route setting method, a reflector, and a multicast distribution route setting program in an IP multicast routing protocol technique capable of setting a scalable transfer route when setting an IP multicast transfer route.

A PIM protocol has been proposed as an IP multicast routing protocol (see, for example, Non-Patent Document 1).
PIM protocol (Protocol Independent Multicast-Sparse Mode (PIM-SM): Protocol Specification (Revised): http://www.ietf.org/internet-drafts/draft-ietf-pim-sm-v2-new-11.text )

  The PIM protocol, which is a representative of the conventional IP multicast routing protocol, needs to periodically exchange Hello messages between PIM routers in order to maintain the PIM adjacency relationship. In addition, since the PIM protocol is a protocol based on the soft state, in order to maintain the set IP multicast distribution route, the JOIN / PRUNE message, which is PIM participation information, is periodically used to prevent the soft state from timing out. Must be sent between PIM neighbors.

  This protocol operation is tuned when building a large-scale IP multicast tree, when there are few IP multicast branches between PIM neighbors, and when the number of PIM neighboring routers is small.

  Therefore, when a large number of PIM edge routers exist at the edge of the P2MP transport network, such as when a large-scale IP multicast distribution route is set across a large P2MP transport network, a large number of PIM edge routers In order to maintain the PIM adjacency relationship, it is necessary to periodically exchange Hello messages with all opposing PIM edge routers. For example, when there are 10,000 PIM edge routers, a full mesh session is established with 10,000 routers facing each other, and PIM Hello is transmitted in a 30-second cycle. As a result, 300 PIM Hello messages are exchanged with each other, wasting the control system power of the PIM edge router and reducing the scalability performance. (See FIG. 12).

  The example of FIG. 12 shows the PIM Hello message exchange relationship between PIM edge routers. As shown in the figure, in order to set up an IP multicast route, it is necessary to construct a PIM adjacency relationship between all downstream edge routers and upstream edge routers. Adjacencies need to be constructed by exchanging Hello messages in full mesh.

  Furthermore, if an IP multicast distribution route is set between the upstream PIM edge router and the downstream PIM edge router in such an environment, for example, when 1000 downstream edge routers participate in IP multicast reception. Will send a JOIN message to the upstream PIM edge router every 30 seconds. When there are 10 IP multicast groups, the upstream PIM edge router receives 300 PIM JOIN messages per second. As a result, the control system power of the PIM edge router is wasted and the scalability performance is reduced (see FIG. 13).

  FIG. 13 shows a conventional PIM JOIN message exchange example. In the example shown in the figure, downstream PIM edge routers R10 to R15 periodically send JOIN messages to upstream routers R01 and R03, and hold an IP multicast distribution route between them. . As shown in this example, when there are many IP multicast branches from the upstream PIM edge router, the upstream PIM edge router needs to periodically receive PIM JOIN messages from a large number of downstream PIM edge routers. Edge scalability performance is degraded.

  Thus, the existing PIM protocol is not necessarily excellent in scalability performance under such an environment.

  The present invention has been made in view of the above points. The PIM protocol is expanded, and the PIM protocol operates in a scalable manner even in the above-described environment. As a result, multicast distribution that enables scalable IP multicast transfer is possible. It is an object to provide a route setting method, a reflector, and a multicast distribution route setting program.

  FIG. 1 is a diagram for explaining the principle of the present invention.

The present invention (Claim 1) is an IP multicast distribution route setting method for setting an IP multicast distribution route in an environment where PIM used for multicast communication in an IP network is operating.
In a system having an edge router existing at the edge of a plurality of P2MP transport networks and a plurality of PIM Hello reflectors that are set at any routable location in the P2MP transport network and transmit / receive Hello messages to / from the edge routers ,
PIM Hello reflector
By directly exchanging Hello messages between a plurality of PIM edge routers and other PIM Hello reflectors remotely, PIM adjacency is acquired and stored in adjacency storage means (step 1).
When the Hello message is received (Step 2), the Hello message stored in the message storage means and the received Hello message are merged (Step 3), and the merged Hello message is obtained by referring to the adjacency storage means. To the adjacent router or reflector (step 4).

The present invention (Claim 2) is an edge router,
Insert IF information that operates the PIM instance of the router into the Hello message, notify the neighboring PIM Hello reflector that the router is participating in PIM multicast routing,
In the PIM Hello reflector,
When the Hello message is received from the edge router, the Hello message stored in the message storage means and the received Hello message are combined, and the IF information of the downstream edge router adjacent to the PIM Hello reflector is also combined. The IF information of the PIM Hello reflector is also stored in the Hello message,
A Hello message is transmitted to all upstream routers adjacent to the PIM Hello reflector acquired by referring to the adjacency storage means.

  In the present invention (Claim 3), in the PIM Hello reflector, the reflector information that the PIM Hello reflector itself peers is set.

The present invention (Claim 4) is an IP multicast distribution route setting method for setting an IP multicast distribution route in an environment where PIM used for multicast communication in an IP network is operating.
Downstream edge router having a plurality of P2MP forwarding network edge routers and a plurality of PIM JOIN reflectors configured to transmit / receive PIM JOIN messages to / from the edge routers set at any routable location in the P2MP forwarding network In a system that sets an IP multicast distribution route between an upstream edge router and the downstream edge router in order to participate in IP multicast reception for an arbitrary multicast group,
The downstream edge router
The PIM JOIN message storing the multicast reception participation information is transferred to the adjacent PIM route reflector obtained by referring to the first adjacency storage means that records the adjacency relationship by IP unicast,
PIM route reflector
When the PIM JOIN message is received from the downstream edge router, the PIM JOIN message is directly received from the adjacent PIM route reflector with reference to the second adjacency storage means that records the adjacency relationship. The JOIN message and multicast reception participation information are collected and transmitted to the PIM route reflector on the route or the adjacent PIM route reflector.

In the downstream edge router, the present invention (Claim 5)
Referring to the first adjacency storing means, multicast reception participation information including its own IF information, participation target multicast group information, and possibly multicast source information with respect to adjacent PIM route reflectors Is stored in a PIM JOIN message, transferred directly by IP unicast,
The PIM route reflector that received the PIM JOIN message from the downstream edge router
When other downstream PIM edge routers do not participate in multicast, the PIM JOIN message is directly transferred to the upstream PIM route reflector obtained by referring to the second adjacency storing means, and the other downstream PIM edge routers are transferred. When sending another PIM JOIN message for multicast participation, the received PIM JOIN message and the multicast reception participation information are collected, and the collected multicast reception participation information is used as the PIM JOIN message to obtain the IP multicast source route. To the upstream PIM route reflector to
The PIM route reflector adjacent to the upstream edge router towards the IP multicast source route is
With reference to the second adjacency storing means, the collected PIM JOIN message is relayed to the upstream edge router toward the IP multicast source route adjacent to the reflector.

Further, the present invention (Claim 6) is a PIM reflector,
When a PIM JOIN message is relayed between route reflectors, the PIM JOIN message is relayed not only to the route reflectors existing on the target IP multicast source route but also to the route reflectors that maintain all PIM adjacencies. .

In addition, the present invention (Claim 7), when stopping reception of a multicast group in which a downstream PIM edge router of a P2MP transport network participates
A PIM PRUNE message is relayed to a remote upstream PIM edge router using a method similar to the method of relaying a PIM JOIN message.

  In the present invention (Claim 8), when a PIM PRUNE message is relayed between route reflectors, not only the route reflectors existing on the route of the target IP multicast source but also all routes having PIM adjacency relationships. The PIM PRUNE message is relayed to the reflector.

  FIG. 2 is a principle configuration diagram of the present invention.

The present invention (Claim 9) is set in any routable place in a P2MP transport network in an environment where PIM used for multicast communication in an IP network is operating, and includes edge routers of a plurality of P2MP transport networks. A reflector for sending and receiving messages,
A message receiving unit 110 that acquires a Hello message from an edge router or other PIM Hello reflector, acquires a PIM adjacency, and stores it in the adjacency storage unit 130;
When the hello message is received by the message receiving means 110, the message processing means 120 for merging the hello message stored in the message storage means 160 and the received hello message;
And a message transmission unit 150 that transmits the merged Hello message to the adjacent router or reflector obtained by referring to the adjacency storage unit 130.

Further, the present invention (Claim 10) is provided in the message receiving means 110.
Means for receiving a Hello message in which IF information for operating the PIM instance of the edge router is inserted from the edge router;
The message processing means 120
The Hello message received from the other edge router stored in the message storage means 160 and the received Hello message are collected, and the IF information of the downstream edge router adjacent to the PIM Hello reflector is also collected. Including means for storing IF information of the PIM Hello reflector in the Hello message,
The message sending means 150
Means for sending a combined Hello message to all upstream routers adjacent to the PIM Hello reflector.

The present invention (Claim 11) has a plurality of P2MP forwarding network edge routers in an environment in which PIM used for multicast communication in an IP network is operating, and a downstream edge router provides IP to any multicast group. A reflector in a system for setting an IP multicast distribution route between an upstream edge router and the downstream edge router in order to participate in multicast reception,
Message receiving means for receiving a PIM JOIN message storing multicast reception participation information from a downstream edge router;
Message processing means for combining the PIM JOIN message received by the message receiving means and the multicast reception participation information;
Referring to the adjacency storing means that records the adjacency relation, the PIM JOIN message is directly used for the adjacent PIM route reflector or the PIM JOIN message created by the message processing means is used as the PIM route reflector on the route. Alternatively, message transmitting means for transmitting to an adjacent PIM route reflector is included.

Further, the present invention (Claim 12) provides a message receiving means,
As multicast reception participation information from the downstream edge router, including IF information that participates in own IP multicast reception, multicast group information to participate, and in some cases, means for acquiring multicast source information,
Message processing means
When other downstream PIM edge routers other than the downstream edge router are not participating in multicast, the PIM JOIN message is directly transferred to the upstream PIM route reflector obtained by referring to the adjacency storing means, and the other downstream PIM When the edge router transmits another PIM JOIN message to participate in multicast, the received PIM JOIN message and multicast reception participation information are collected, and the collected multicast reception participation information is used as a PIM JOIN message to perform IP multicast. Including means for transmitting to an upstream PIM route reflector towards the source path;
When the reflector is adjacent to the upstream edge router toward the IP multicast source route, refer to the adjacency storage means and collect the PIM JOIN collected in the upstream edge router toward the IP multicast source route adjacent to the reflector. Including means for relaying the message.

  The present invention (Claim 13) is a multicast distribution route setting program for causing a computer to function as the reflector according to any one of Claims 9 to 12.

  As described above, according to the present invention, the PIM protocol is extended and the PIM protocol operates in a scalable manner even in the above-described environment, and as a result, scalable IP multicast transfer is possible.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 3 shows the configuration of the communication system in the first embodiment of the present invention.

  In the IP multicast communication network, the system shown in FIG. 1 is configured such that, in an environment in which the PIM protocol is operating as a multicast routing protocol, an IP multicast distribution route is set to a remote P2MP transport network (L2 broadcast network, P2MP MPLS tunnel network, IP This is a system for setting across a multicast GRE tunnel network.

The PIM protocol is
“Protocol Independent Multicast-Sparse Mode (PIM-SM): Protocol Specification (Revised): http://www.ietf.org/internet-draft/draft-ietf-pim-sm-v2-new-11.txt” To do.

  In the system of FIG. 3, in order to maintain the PIM adjacency relationship between the PIM routers R00, R01 to R03, R10 to R15 existing at the edge of the P2MP transport network, any routable place in the intermediate P2MP transport network PIM message reflectors RR1 to RR7 that maintain PIM adjacency are arranged by exchanging Hello messages with P2MP forwarding network edge routers by direct unicast routing.

  FIG. 4 shows the configuration of the PIM Hello reflector in the first embodiment of the present invention.

  The PIM Hello reflector 100 shown in the figure includes a message receiving unit 110, a message processing unit 120, an adjacency storage unit 130, an IP routing protocol control unit 140, a message transmission unit 150, and a message storage unit 160.

  The message receiving unit 110 receives a Hello message from another PIM reflector or router, stores the message in the message storage unit 160, and stores IF information, which is a PIM adjacency included in the message, in the adjacency storage unit 130. To do.

  The adjacency storage unit 130 holds the PIM adjacency relationship (IF information) set by the message receiving unit 110. FIG. 5 shows the adjacency held by the PIM remote adjacency holding unit 122 of each reflector. For example, in the reflector RR1 in FIG. 3, the routers R10 and R11 and the reflector RR4 are adjacent to each other, and the IF addresses of these routers or reflectors are stored.

  The message processing unit 120 bundles the Hello message received from the router or reflector by the message receiving unit 110 and the Hello message received from another PIM edge router stored in the message storage unit 160, and the PIM reflector 100 The IF information of the adjacent downstream PIM edge router is acquired from the adjacency storage unit 130 and bundled. Further, its own IF information is also stored in the Hello message, and by referring to the adjacency storage unit 130, information on all upstream routers adjacent to itself and information on PIM edge routers in which PIM is adjacent to each other are stored. The PIM edge router is notified via the message transmission unit 150 to the upstream router. When these processes are completed, the received Hello message is stored in the message storage unit 160.

  If the message processing unit 120 is adjacent to the upstream PIM edge router of the P2MP transport network, the message processing unit 120 transmits the relayed Hello message to the upstream PIM edge router, and Hello messages are also received from other PIM edge routers.

  The IP routing protocol control unit 140 routes the IP multicast route to the message output unit 150.

  FIG. 6 shows the configuration of the PIM router in the first embodiment of the present invention.

  The PIM router 200 includes a message input / output unit 210, a message creation unit 220, and an IF address storage unit 230.

  The message input / output unit 210 transmits / receives a message to / from another router or reflector, extracts an IF address included in the received message, and stores the IF address in the IF address storage unit 230.

  When the router exists at the edge of the P2MP transport network, the message creation unit 220 refers to the IF address storage unit 230 for the PIM Hello reflector 200 for the IF address that operates the PIM instance of the router. And the IF address is inserted into a Hello message to notify that the router is participating in PIM multicast routing.

  The IF address storage unit 230 stores an IF address (adjacency relationship).

  A specific operation will be described below.

  In the example of FIG. 3, it is assumed that upstream PIM edge routers PIM R00 to R03 exist, downstream PIM edge routers PIM R10 to R15 exist, and a P2MP forwarding network exists between these PIM edge routers. This P2MP transfer network is assumed to have a transfer function for distributing IP multicast data from all upstream edge routers to downstream edge routers. Here, the meaning of upstream and downstream is assumed to be a case where the IP multicast distribution route is set toward the upstream of the upstream router with the direction of the IP multicast source transmitting the IP multicast data as the upstream.

  In the present invention, PIM Hello reflectors RR1 to RR7 are arranged in the P2MP transport network. Reflector RR1 maintains an adjacent relationship with routers R10 and R11, reflector RR2 maintains an adjacent relationship with routers R12 and R13, reflector R3 maintains an adjacent relationship with routers R14 and R15, and reflector RR6 has routers R00 and R01. The reflector RR7 maintains the adjacent relationship with the routers R02 and R03, the reflector RR4 maintains the adjacent relationship with the reflectors RR1, RR2, RR5 and RR6, and the reflector RR5 has the adjacent relationship with RR3, RR7 and RR4. Holding. These adjacency relationships are held in the adjacency storage unit 130 when a message is received.

  Using this example, how the PIM adjacency relationship is maintained between the downstream and upstream PIM edge routers will be described.

  First, the downstream router R10 stores its own PIM participation IF (interface) information R10 in a Hello message and transmits the Hello message remotely to the reflector RR1 in the adjacent relationship by IP unicast. Similarly, the downstream router R11 also stores the participation IF information of R11 and transmits a Hello message to the reflector RR2. The reflector RR1 that has received these Hello messages from downstream neighbors stores the participation IF information in the adjacency storage unit 130, and summarizes the information in the message processing unit 120. R11 is inserted into the Hello message. Then, the message transmission unit 150 refers to the adjacency storage unit 130 to acquire and transmit IF information of RR4 set as an upstream PIM adjacency. At this time, the reflector RR4 receives the downstream PIM adjacency information from the reflectors RR2 and RR5, and the reflectors RR2 and RR3 also receive the PIM adjacency information from the routers R12 and R13 and R14 and R15, respectively. Since the information is held in the adjacency storage unit 130, the reflector RR4 collects all the received PIM adjacency information in the message processing unit 120 as R10 + R11 + R12 + R13 + R14 + R15 information as upstream PIM via the message transmission unit 150. It is sent to the adjacent reflector RR6. At this time, the reflector RR6 notifies the upstream PIM adjacent information equally to the upstream adjacent reflector R00 and the router R01. As a result, the upstream PIM edge routers R00 and R01 can grasp their remote downstream neighboring routers R11 to R15.

  Further, by the same operation, the upstream PIM edge router also relays the upstream PIM neighbor to the downstream PIM edge router via the PIM Hello reflector, so that the downstream PIM edge router can grasp the upstream PIM neighbor.

  The PIM adjacency changes according to the activation / down of the PIM router, but since the relay of these Hello messages operates incrementally, it is possible to change the information content to be transferred according to the change.

  Furthermore, since it is possible to arbitrarily set the arrangement of the route reflectors, the relationship between each peering, and the number of relay stages, various controls are possible. Here, as a method of setting the peering to the reflector, it is possible to perform peering by itself or to set the reflector information in the reflector in advance by the operator.

  Moreover, since it becomes possible to change the transmission cycle of a Hello message in relaying, the scalability performance accompanying transmission of a Hello message can be freely controlled.

  In addition, by using such a hierarchical relay mechanism, the number of neighbors that the downstream and upstream PIM edge routers must maintain adjacent relations can be greatly reduced, which contributes to improvement in scalability performance.

  FIG. 7 shows a PIM Hello message format in the first embodiment of the present invention. A Hello reflector option is newly defined in the PIM Hello message, and PIM participation IF information of the downstream PIM edge router is stored in the option field. This information is added and stored every time the number of downstream PIM adjacent edge router IFs increases in the reflector to be relayed.

  Next, the flow of transmitting / receiving a PIM remote Hello message will be described.

  FIG. 8 shows an example of transmission / reception of a PIM remote Hello message according to the first embodiment of the present invention.

  1) When PIM reflector # 1 receives a Hello message from PIM router # 1 in message receiving unit 110, PIM reflector # 2 and PIM router adjacent to PIM reflector # 2 are referred to in adjacency storage unit 130 in message processing unit 120. The IF information of # 2 is acquired, and the received PIM adjacent information (R # 1) is relayed to the PIM reflector # 2 and the PIM router # 2 via the message transmission unit 150.

  2) When PIM reflector # 1 receives PIM adjacency information (R # 3, R # 4) (PIM remote Hello message) from PIM reflector # 2 at message receiving section 110, message processing section 120 performs adjacency storage section. Referring to 130, IF information of PIM routers # 1 and # 2 is acquired, and the Hello message received by PIM routers # 1 and # 2 is relayed via message transmission unit 150.

  3) When the message receiving unit 110 receives a Hello message from the PIM router # 2 in the PIM reflector # 1, the message processing unit 120 refers to the adjacency storage unit 130, and the IF of the PIM router # 1 and the PIM reflector # 2 Information is acquired, and PIM adjacent information (R # 2) (PIM remote Hello message) received from PIM router # 2 is relayed to PIM router # 1 and PIM reflector # 2 via message transmitter 150.

  4) Thereby, for example, the PIM reflector # 2 refers to the information in the adjacency storage unit 130 for the PIM adjacency information R # 3 and R # 4 (PIM remote Hello message), and performs PIM via the message transmission unit 150. Relay to reflector # 1.

[Second Embodiment]
In this embodiment, a PIM JOIN / PRUNE reflector system will be described.

  FIG. 9 shows a configuration of a communication system according to the second embodiment of the present invention.

  In the example shown in the figure, it is assumed that upstream PIM edge routers PIM R00 to R03 exist, downstream PIM edge routers PIM R10 to R15 exist, and a P2MP forwarding network exists between these PIM edge routers. This P2MP transfer network has a transfer function for distributing IP multicast data from all upstream edge routers to downstream edge routers. Further, it is assumed that RR1 to RR7 exist as JOIN / PRUNE reflectors in the P2MP transport network.

  The JOIN / PRUNE reflector and router have the same configuration as that of the first embodiment described above, but the operations of the message processing unit 120 of the JOIN / PRUNE reflector 100 and the message creation unit 220 of the router 200 are the same. Different. Also, multicast participation information is stored in the message storage unit 160 of the reflector 100. Here, the multicast participation information includes IF information that participates in IP multicast reception, a multicast group to be participated, multicast source information, and the like.

  When the router 200 is a downstream PIM edge router (for example, R10 to R15 in FIG. 9), IF information that participates in reception of its own IP multicast with respect to the PIM route reflector having the adjacent relationship with the router. Then, the PIM JOIN message storing the multicast group information to be joined and, in some cases, the multicast source information is directly transferred by IP unicast.

  When the JOIN / PRUNE reflector 100 is a route reflector and receives a PIM JOIN message from the downstream edge node, the message processing unit 120 refers to the adjacency storage unit 130 and refers to the IF of the reflector that is adjacent to the JOIN / PRUNE reflector 100. The information is acquired, and it is determined whether or not other downstream PIM edge routers are participating in multicast for the reflector by referring to the message storage unit 160. The PIM JOIN message is transferred as is.

  When the message processing unit 120 receives another PIM JOIN message for multicast participation from the downstream PIM edge router, the message reception unit 120 receives the received PIM JOIN message and the multicast reception stored in the message storage unit 160. Summarize participation information. Then, the collected multicast reception participation information is transmitted as a PIM JOIN message from the message transmission unit 150 to the upstream PIM route reflector toward the IP multicast source route.

  When the reflector is adjacent to a plurality of downstream PIM edge routers in the P2MP transfer network, the collected PIN JOIN message is relayed to the upstream PIM edge router toward the IP multicast route.

  Hereinafter, this will be specifically described with reference to FIG.

  In FIG. 9, downstream edge routers R10 to R15 PIMJOIN R01, which is an upstream PIM edge router, to set an IP multicast transfer path between them.

  First, the edge router R10 stores R10 information that is its own PIM JOIN participation IF information and G1 that is multicast group address information that it wants to participate in reception in a JOIN message and transfers it to the reflector RR1 that is adjacent to the upstream PIM. At this time, the reflector RR1 has also received the same reception participation request from another downstream PIM edge node R11.

  Therefore, the message processing unit 120 of the reflector RR1 collects these pieces of information and indicates that there are routers R10 and R11 that want to join the downstream multicast group G1 as JOIN (G1, R10 + R11). Transfer to RR4.

  At this time, the reflector RR1 is aware of the upstream G1 address and sends this message to the adjacent reflector RR4 existing on the route of the router R01 connected to the source of G1. For example, when only peering is set to the reflector, all the JOIN information in FIG. 9 is advertised to the PIM router. Avoiding this, the aggregated JOIN is transmitted only to the necessary PIM router, that is, only to the PIM router in the middle of the JOIN destination route. Note that this method can be realized by notifying all reflectors of peering relationships of other reflectors in advance using the peering relationship information.

  As described above, in the present invention, when a JOIN / PRUNE message is transmitted between reflectors, it is possible to relay the message only to the reflector on the route, and it is also possible to relay the message to all the adjacent reflectors. Is possible. The example of FIG. 9 shows an example in which a message is transmitted only to the reflector on the route.

  In this case, the reflector RR4 that has received the message has received the JOIN message from the reflectors RR2 and RR5, the reflector RR2 has received the JOIN message from the routers R12 and R13, and the reflector RR3 has received the JOIN message from the routers R14 and R15. Therefore, the reflector RR4 transmits a JOIN message to the reflector RR6 via the message transmission unit 150 in the message processing unit 120 as a JOIN (G1, R10 + R11 + R12 + R13 + R14 + R15) in the message processing unit 120.

  Further, the reflector RR6 relays the JOIN message toward the router R01 on the route of the G1 source. In this way, a multicast transfer path is established between the upstream PIM edge router R01 and the downstream PIM edge routers R10 to R15.

  Next, the PIMJOIN / PRUNE message transferred above will be described.

  FIG. 10 shows the structure of the PIM JOIN / PRUNE message in the second embodiment of the present invention. In the message format shown in the figure, a downstream node address for notifying downstream PIM router information is provided in the JOIN message. In this case, when the messages are aggregated by the message processing unit 120 of the JOIN reflector, the downstream PIM router information is also aggregated.

  Next, the flow of transmitting / receiving a PIM remote JOIN message will be described.

  FIG. 11 shows an example of transmission / reception of a PIM remote JOIN message according to the second embodiment of the present invention.

  1) The message creation unit 220 of the router # 1 stores its router information in a PIM JOIN message, and transmits it to the upstream adjacent upstream PIM reflector # 1 toward the IP Mcast Source acquired from the IF address storage unit 230.

  2) The message creation unit 220 of the router # 0 stores its router information in a PIM JOIN message and transmits it to the upstream adjacent upstream PIM reflector # 1 toward the IP Mcast Source acquired from the IF address storage unit 230.

  3) Reflector # 1, which has received the PIM JOIN message from router # 1 and router # 0, stores two PIM JOIN messages in message storage unit 160. In the message processing unit 120, a plurality of PIM JOIN messages are merged and transmitted to the upstream adjacent upstream PIM reflector # 2 toward the IP Mcast Source based on the adjacency information acquired from the adjacency storage unit 130.

  4) When the reflector # 2 receives the merged PIM JOIN message from the reflector # 1, the reflector # 2 transmits the message to the adjacent upstream PIM router # 3 based on the adjacency information acquired from the adjacency storage unit 130.

  5) When the PIM router # 3 receives the PIM JOIN message from the reflector # 2, the PIM router # 3 transmits the message to the adjacent upstream router toward the PIM Mcast Source based on the adjacency information acquired from the adjacency storage unit 130.

  The same operation as above is also performed when PIM leaves (processing to delete the branch of the tree up to the point of leaving by sending a PIM PRUNE message to leave the multicast reception of the IP multicast tree constructed by PIM) To do. Specifically, the downstream PIM edge router serving as a leaf is detached from the PIM tree by relaying the PRUNE message between the reflectors.

  By using such a relay mechanism, even when the number of IP multicast branches is large, it can be reduced by relaying periodic message transmission based on the PIM soft state. As a result, scalability performance is improved. Furthermore, since the transmission timing of the periodic message can be changed between the reflectors, the network performance can be controlled.

  Further, it is possible to construct the operation of each component of the reflector shown in FIG. 4 as a program and install it in a computer used as a reflector, or distribute it via a network.

  The present invention is not limited to the above-described embodiment, and various modifications and applications can be made within the scope of the claims.

  The present invention is applicable to a route setting technique for setting a wide area across a P2MP transfer network having a P2MP transfer route corresponding to an IP multicast route without the IP multicast routing protocol operating.

  Further, the present invention can be applied when a customer's IP multicast network is set in a wide area between PEs in a VPN such as RFC2547bis.

It is a figure for demonstrating the principle of this invention. It is a principle block diagram of this invention. It is a block diagram of the communication system in the 1st Embodiment of this invention. It is a block diagram of the PIM Hello reflector in the 1st Embodiment of this invention. It is a figure which shows the PIM adjacency relationship which the adjacency memory | storage part in the 1st Embodiment of this invention hold | maintains. It is a block diagram of the PIM router in the 1st Embodiment of this invention. It is a PIM Hello message format in the 1st Embodiment of this invention. It is an example of transmission / reception of the PIM remote Hello message in the 1st Embodiment of this invention. It is a block diagram of the communication system in the 2nd Embodiment of this invention. It is a PIM JOIN message format in the 2nd Embodiment of this invention. It is an example of the PIM remote JOIN message transmission / reception in the 2nd Embodiment of this invention. It is a figure for demonstrating the scalability problem of Hello adjacency in PIM Mcast. It is a figure for demonstrating the scalability problem accompanying the periodic Join message transmission in PIM Mcast.

Explanation of symbols

100 reflector, PIM Hello reflector 110 message receiving unit, message receiving unit 120 message processing unit, message processing unit 130 adjacency storage unit, adjacency storage unit 140 IP routing protocol control unit 150 message transmission unit, message transmission unit 160 message storage unit , Message storage unit 200 PIM router 210 message input / output unit 220 message creation unit 230 IF address storage unit 240 adjacency storage unit

Claims (13)

An IP multicast distribution route setting method for setting an IP multicast distribution route in an environment where PIM (Protocol Independent Multicast) used for multicast communication in an IP (Internet Protocol) network is operating,
Edge routers that exist at the edge of multiple P2MP (Point-to-Multipoint) transport networks and multiple PIMs that are set at any routable location in the P2MP transport network and send and receive Hello messages to and from these edge routers In a system with a Hello reflector,
The PIM Hello reflector is
By exchanging the Hello message directly between a plurality of PIM edge routers and other PIM Hello reflectors, the PIM adjacency relationship (IF information: interface information) is acquired and stored in the adjacency storage means. ,
When the Hello message is received, the Hello message stored in the message storage means and the received Hello message are merged, and the adjacent Hello message or the reflector obtained by referring to the adjacency storage means is acquired. A multicast delivery route setting method, characterized by: In the edge router,
Insert IF information that operates the PIM instance of the router into a Hello message, notify the adjacent PIM Hello reflector that the router is participating in PIM multicast routing,
In the PIM Hello reflector,
When the Hello message is received from the edge router, the Hello message stored in the message storage unit and the received Hello message are combined, and IF information of the downstream edge router adjacent to the PIM Hello reflector is also obtained. In summary, the IF information of the PIM Hello reflector is also stored in the Hello message,
The multicast delivery route setting method according to claim 1, wherein the Hello message is transmitted to all upstream routers adjacent to the PIM Hello reflector acquired with reference to the adjacency storage unit.   The multicast delivery route setting method according to claim 1 or 2, wherein the PIM Hello reflector sets reflector information that the PIM Hello reflector itself peers with. An IP multicast distribution route setting method for setting an IP multicast distribution route in an environment where PIM (Protocol Independent Multicast) used for multicast communication in an IP network is operating,
Downstream edge router having a plurality of P2MP forwarding network edge routers and a plurality of PIM JOIN reflectors configured to transmit / receive PIM JOIN messages to / from the edge routers set at any routable location in the P2MP forwarding network In a system that sets an IP multicast distribution route between an upstream edge router and the downstream edge router in order to participate in IP multicast reception for an arbitrary multicast group,
The downstream edge router is
The PIM JOIN message storing the multicast reception participation information is transferred to the adjacent PIM route reflector obtained by referring to the first adjacency storage means that records the adjacency relationship by IP unicast,
The PIM route reflector is
When the PIM JOIN message is received from the downstream edge router, the PIM JOIN message is received as it is or received from the adjacent PIM route reflector with reference to the second adjacency storage means that records the adjacency relationship. A multicast delivery route setting method comprising: combining the PIM JOIN message and multicast reception participation information, and transmitting the information to a PIM route reflector on a route or an adjacent PIM route reflector. The downstream edge router is
Referring to the first adjacency storing means, the multicast including its own IF information, participation multicast group information, and possibly multicast source information for the adjacent PIM route reflector The received participation information is stored in the PIM JOIN message, transferred directly by IP unicast,
The PIM route reflector that has received the PIM JOIN message from the downstream edge router is:
When other downstream PIM edge routers do not participate in multicast, the PIM JOIN message is transferred as it is to the upstream PIM route reflector obtained by referring to the second adjacency storage means, and the other downstream PIM When the edge router transmits another PIM JOIN message for multicast participation, the received PIM JOIN message and the multicast reception participation information are collected, and the collected multicast reception participation information is set as a PIM JOIN message. Sent to the upstream PIM route reflector towards the multicast source path,
A PIM route reflector adjacent to an upstream edge router towards the IP multicast source path is:
The multicast delivery route setting method according to claim 4, wherein the collected PIM JOIN message is relayed to an upstream edge router toward the IP multicast source route adjacent to the reflector by referring to the second adjacency storage means. . The PIM reflector is
When the PIM JOIN message is relayed between the route reflectors, the PIM JOIN message is sent not only to the route reflectors existing on the target IP multicast source path but also to the route reflectors holding all PIM adjacencies. The multicast distribution route setting method according to claim 4 or 5, wherein relaying is performed. When stopping the reception of the multicast group in which the downstream PIM edge router of the P2MP transport network participates,
The multicast delivery route setting method according to claim 4, wherein a PIM PRUNE message is relayed to a remote upstream PIM edge router using a method similar to the method of relaying the PIM JOIN message.   When the PIM PRUNE message is relayed between the route reflectors, the PIM PRUNE message is relayed not only to the route reflectors existing on the route of the target IP multicast source but also to the route reflectors having all PIM adjacency relationships. The multicast delivery route setting method according to claim 7. In an environment where PIM (Protocol Independent Multicast) used for multicast communication in an IP network is operating, it is set at any routable location in the P2MP transport network, and messages are sent to and received from edge routers in multiple P2MP transport networks A reflector,
A message receiving means for obtaining a Hello message from the edge router or other PIM Hello reflector, obtaining a PIM adjacency and storing it in an adjacency storage means;
When receiving the Hello message in the message receiving means, message processing means for merging the Hello message stored in the message storage means and the received Hello message;
Message transmission means for transmitting the merged Hello message to the adjacent router or reflector obtained by referring to the adjacency storage means;
The reflector characterized by having. The message receiving means includes
Means for receiving from the edge router a Hello message in which IF information operating the PIM instance of the edge router is inserted;
The message processing means includes
The Hello message received from the other edge router stored in the message storage means and the received Hello message are summarized, and IF information of the downstream edge router adjacent to the PIM Hello reflector is also summarized. Including means for storing IF information of the PIM Hello reflector in the Hello message,
The message transmission means includes:
Including means for sending a combined Hello message to all upstream routers adjacent to the PIM Hello reflector,
The reflector according to claim 9. In an environment where PIM (Protocol Independent Multicast) used for multicast communication in an IP network is operating, it has multiple P2MP forwarding network edge routers, and downstream edge routers participate in IP multicast reception for any multicast group Therefore, a reflector in a system that sets an IP multicast distribution route between an upstream edge router and the downstream edge router,
Message receiving means for receiving a PIM JOIN message storing multicast reception participation information from the downstream edge router;
Message processing means for combining the PIM JOIN message received by the message receiving means and the multicast reception participation information;
Referring to the adjacency storing means that records the adjacency relation, the PIM JOIN message is directly used for the adjacent PIM route reflector, or the PIM JOIN message created by the message processing means is used as the PIM on the route. A message transmission means for transmitting to a route reflector or an adjacent PIM route reflector;
The reflector characterized by having. The message receiving means includes
As the multicast reception participation information from the downstream edge router, including IF information that participates in its own IP multicast reception, multicast group information to participate, and in some cases, means for obtaining multicast source information,
The message processing means includes
When other downstream PIM edge routers other than the downstream edge router do not participate in multicast, the PIM JOIN message is transferred as it is to the upstream PIM route reflector obtained by referring to the adjacency storage unit, and the other When the downstream PIM edge router transmits another PIM JOIN message for multicast participation, the received PIM JOIN message and the multicast reception participation information are collected, and the collected multicast reception participation information is combined with the PIM JOIN message. Including means for causing an upstream PIM route reflector to send to the IP multicast source route,
When the reflector is adjacent to an upstream edge router toward the IP multicast source route, the adjacent relationship storage unit is referred to and the upstream edge router toward the IP multicast source route adjacent to the reflector is collected. The reflector according to claim 11, comprising means for relaying a PIM JOIN message.   A multicast delivery route setting program for causing a computer to function as the reflector according to claim 9.

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