VPN instances support MSDP. MSDP peer relationships can be set up between multicast router interfaces in the same public or VPN instance. MSDP peers exchange source active (SA) messages to implement inter-domain VPN multicast.
Multicast routers on which multi-instance is applied maintain a set of MSDP mechanisms for each instance, including the SA cache, peer connection, timer, sending cache, and cache area for PIM information exchange. At the same time, information is isolated between different instances. Consequently, only the routers in the same VPN instance can exchange MSDP information and PIM-SM information.