1-11 MSDP ConfigurationWhen configuring MSDP, go to these sections for information you are interested in:z MSDP Overviewz MSDP Configuration Task Listz Displaying and Maintaining MSDPz MSDP Configuration Examplesz Troubleshooting MSDPz The term “router” in this document refers to a router in a generic sense or a Layer 3 switch runningthe MSDP protocol.z For details about the concepts of designated router (DR), bootstrap router (BSR), candidate-BSR(C-BSR), rendezvous point (RP), candidate RP (C-RP), shortest path tree (SPT) and rendezvouspoint tree (RPT) mentioned in this manual, refer to PIM Configuration in the IP Multicast Volume.MSDP OverviewIntroduction to MSDPMulticast source discovery protocol (MSDP) is an inter-domain multicast solution developed to addressthe interconnection of protocol independent multicast sparse mode (PIM-SM) domains. It is used todiscover multicast source information in other PIM-SM domains.In the basic PIM-SM mode, a multicast source registers only with the RP in the local PIM-SM domain,and the multicast source information of a domain is isolated from that of another domain. As a result, theRP is aware of the source information only within the local domain and a multicast distribution tree isbuilt only within the local domain to deliver multicast data from a local multicast source to local receivers.If there is a mechanism that allows RPs of different PIM-SM domains to share their multicast sourceinformation, the local RP will be able to join multicast sources in other domains and multicast data canbe transmitted among different domains.MSDP achieves this goal. With MSDP peer relationships established between appropriate routers in thenetwork, the RPs of different PIM-SM domains are interconnected with one another. Source active (SA)messages are exchanged between these MSDP peers and thus the multicast source information isshared among these different domains.
