Operation Manual – MulticastH3C S5500-EI Series Ethernet Switches Chapter 8 MSDP Configuration8-1Chapter 8 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 MSDPNote:The term “router” in this document refers to a router in a generic sense or a Layer 3switch running the MSDP protocol.8.1 MSDP Overview8.1.1 Introduction to MSDPMulticast source discovery protocol (MSDP) is an inter-domain multicast solutiondeveloped to address the interconnection of protocol independent multicast sparsemode (PIM-SM) domains. It is used to discover multicast source information in otherPIM-SM domains.In the basic PIM-SM mode, a multicast source registers only with the RP in the localPIM-SM domain, and the multicast source information of a domain is isolated from thatof another domain. As a result, the RP is aware of the source information only within thelocal domain and a multicast distribution tree is built only within the local domain todeliver multicast data from a local multicast source to local receivers. If there is amechanism that allows RPs of different PIM-SM domains to share their multicastsource information, the local RP will be able to join multicast sources in other domainsand multicast data can be transmitted among different domains.MSDP achieves this objective. By establishing MSDP peer relationships among RPs ofdifferent PIM-SM domains, source active (SA) messages can be forwarded amongdomains and the multicast source information can be shared.
