Operation Manual – MulticastH3C S5500-EI Series Ethernet Switches Chapter 8 MSDP Configuration8-2Caution:z MSDP is applicable only if the intra-domain multicast protocol is PIM-SM.z MSDP is meaningful only for the any-source multicast (ASM) model.8.1.2 How MSDP WorksI. MSDP peersWith one or more pairs of MSDP peers configured in the network, an MSDPinterconnection map is formed, where the RPs of different PIM-SM domains areinterconnected in series. Relayed by these MSDP peers, an SA message sent by anRP can be delivered to all other RPs.Figure 8-1 Where MSDP peers are in the networkAs shown in Figure 8-1, an MSDP peer can be created on any PIM-SM router. MSDPpeers created on PIM-SM routers that assume different roles function differently.1) MSDP peers on RPsz Source-side MSDP peer: the MSDP peer nearest to the multicast source (Source),typically the source-side RP, like RP 1. The source-side RP creates SA messagesand sends the messages to its remote MSDP peer to notify the MSDP peer of thelocally registered multicast source information. A source-side MSDP must becreated on the source-side RP; otherwise it will not be able to advertise themulticast source information out of the PIM-SM domain.z Receiver-side MSDP peer: the MSDP peer nearest to the receivers, typically thereceiver-side RP, like RP 3. Upon receiving an SA message, the receiver-sideMSDP peer resolves the multicast source information carried in the message andjoins the SPT rooted at the source across the PIM-SM domain. When multicast
