MSDP support for VPNs

Interfaces on the multicast routers in a VPN can set up MSDP peering relationships with each other. By exchanging SA messages between MSDP peers, multicast data can be transmitted in a VPN across different PIM-SM domains.

To support MSDP for VPNs, a multicast router that runs MSDP maintains an independent set of MSDP mechanism for each VPN that it supports. These mechanisms include SA message cache, peering connection, timers, sending cache, and cache for exchanging PIM messages.

One VPN is isolated from another, and MSDP and PIM-SM messages can be exchanged only within the same VPN.