Multicast Source Discovery Protocol (MSDP) is an inter-domain multicast protocol that sets up an MSDP peer relationship between Rendezvous Points (RPs) in different PIM-SM domains. MSDP peers exchange (S, G) information by sending SA messages, so that the MSDP peers can share multicast source information and hosts can receive multicast data from sources in another PIM-SM domain.
When a multicast network is divided into multiple PIM-SM domains, MSDP is required to connect Rendezvous Points (RPs) in different domains and enable RPs to share multicast source information. As a result, hosts in the local PIM-SM domain can receive multicast data sent by multicast sources in other domains.
Anycast-RP allows you to configure several Rendezvous Points (RPs) with the same address in a PIM-SM domain. Peer relationships are established between RPs so that the multicast source can register with the topologically closest RP and the multicast receiver can join the closest RP. This alleviates burdens on RPs, implements RP backup, and optimizes multicast forwarding paths.
MSDP peers communicate through TCP connections. You can flexibly control the sessions set up between MSDP peers by ending or reestablishing TCP connections. In addition, you can also adjust the interval for retrying to set up MSDP peer connections and configure MSDP peer authentication to improve the security of TCP connections.
MSDP peers share (S, G) information by exchanging SA messages. You can configure the capacity of the SA cache, enable the sending of SA Request messages, enable the encapsulation of multicast data into SA messages, and create filtering policies for SA messages and SA Request messages.
Maintaining MSDP involves deleting MSDP peer statistics and (S, G) information in the SA cache, monitoring MSDP running status, and debugging MSDP for fault locating.
This section provides MSDP configuration examples. These examples help you learn how to implement MSDP RPF check through BGP or static RPF neighbors, how to implement PIM-SM inter-domain multicast and inter-AS multicast, and how to configure Anycast-RP in a PIM-SM domain.