A method and device for implementing layer-3 multicast on-demand routing based on pim-ssm

Abstract

The present invention discloses a method and equipment for realizing three-layer multicast on-demand route selection based on PIM-SSM. When the interface is configured with corresponding on-demand path information, or the multicast join message carries on-demand path information, determine whether it is the device corresponding to the first hop in the on-demand path information link; if it is judged to be yes, According to the conventional multicast joining process, establish a multicast routing table entry, and forward the multicast joining message that does not carry the on-demand path information upstream; if the judgment is no, then establish a multicast routing table entry according to the on-demand path information , and forward the multicast join message carrying the on-demand path information to the device corresponding to the previous hop in the on-demand path information link. In the present invention, the flexibility of deploying the forwarding path of the multicast data flow is improved, and the manageability of the forwarding of the multicast data flow is enhanced.

Description

technical field [0001] The invention relates to the communication field, in particular to a method and equipment for realizing three-layer multicast on-demand routing. Background technique [0002] PIM (Protocol Independent Multicast) is a multicast technology that can use unicast static routing or unicast routing table generated by any unicast routing protocol to provide routing for IP (Internet Protocol, Internet Protocol) multicast . [0003] PIM uses the RPF (Reverse Path Forwarding) mechanism to forward multicast packets. When a multicast packet arrives at the local device, it first performs an RPF check. If the RPF check passes, a corresponding multicast routing table entry is created to forward the multicast packet; if the RPF check fails, the packet is discarded. arts. Wherein, the implementation method of the RPF mechanism is: according to the address of the multicast source, search for a unicast route to the nearest next-hop outbound interface of the multicast s...

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Problems solved by technology

[0005] Based on the multicast forwarding tree established by the above method, its routing selection depends entirely on the RPF calculation of unicast routing, and the generated forwarding path cannot be manually intervened, and the multicast forwarding tree cannot be established on demand.

[0006] In the prior art, a multicast forwarding tree can also be established through static multicast routing, that is, according to the multicast source address, the RPF interface of the upstream device (for the device, the incoming interface of the multicast data flow) is statically set on different devices. ), to a certain extent realize the establishment of a multicast forwarding tree on demand, but the existing static multicast routing method can only establish a corresponding multicast forwarding tree for the multicast source address. Different users on the device (users connected through different interfaces of the device) generate different multicast forwarding trees to figure 2 The scenario shown is taken as an example. When both Client (client)_9A and Client_9B want to receive the multicast data stream sent by the multicast data source, the existing technology cannot generate different multicast forwarding paths for Client_9A and Client_9B respectively, and the multicast data The flexibility of flow forwarding path deployment and the poor manageability of multicast data flow forwarding

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