Advanced Routing mode supports Multicast Source Discovery Protocol (MSDP) in PIM Sparse Mode (PIM-SM). MSDP-enabled firewalls in one domain peer with MDSP-enabled devices in a different domain or autonomous system. The peers exchange control information and discover multicast sources outside their own domain. MSDP tracks active sources and shares them with configured peers. MSDP reduces the complexity of interconnecting multiple PIM-SM domains by allowing the domains to use an interdomain source tree.

In the sample MSDP topology, the multicast source and receiver are in separate domains. In each multicast domain is a single RP for a given multicast group. Using MSDP, RP_1 informs RP_2 of the active sources for which RP_1 acts as Rendezvous Point. RP_2 is able to create the multicast tree across the domain border.

MSDP uses well-known TCP port 639 for peering. The peer with the higher IP address listens on port 639; the peer with the lower IP address attempts an active connection to port 639. Before you configure MSDP, be familiar with RFC 3618. The following task assumes you have IPv4 multicast configured already.

Supported MSDP message types are:

MSDP TCP connections between RP routers require an underlying IP unicast network. BGP IPv4 unicast must participate to confirm the reverse-path forwarding (RPF) check with a peer, thus keeping loop-free forwarding between domains.

You can Create Multicast Routing Profiles before configuration or while in the process of configuring MSDP.