Overview MSDP

RP in the PIM-SM network only knows the multicast source information in the multicast domain, but in the actual application, the whole network is divided to multiple multicast domains. In the case, the RP in the domain cannot know the multicast source information out of the domain and the receiver cannot receive the multicast packets of other domains.

MSDP (Multicast Source Discovery Protocol) provides one multicast cross-domain solution. The MSDP mechanism transmits the multicast source information of the multicast domain to the RP of another multicast domain, and the RP in the other multicast domain can initiate adding to the multicast source of the multicast domain and set up the multicast distributing tree, so as to realize the cross-domain transmission of the multicast packets.