MSDP Anycast RP

MSDP Anycast RP is a method of providing intra-domain redundancy and load-balancing between multiple Rendezvous Points (RP) in a Protocol Independent Multicast Sparse mode (PIM-SM) network. It is accomplished by configuring all RPs within a domain with the same anycast RP address which is typically a loopback IP address. Multicast Source Discovery Protocol (MSDP) is used between all of the RPs in a mesh configuration to keep all RPs in sync regarding the active sources.

PIM-SM routers are configured to register (statically or dynamically) with the RP using the same anycast RP address. Since multiple RPs have the same anycast address, an Interior Gateway Protocol (IGP) such as OSPF routes the PIM-SM router to the RP with the best route. If the PIM-SM routers are distributed evenly throughout the domain, the loads on RPs within the domain will be distributed. If the RP with the best route goes out of service, the PIM-SM router’s IGP changes the route to the closest operating RP that has the same anycast address.

This configuration works because MSDP is configured between all of the RPs in the domain. Consequently, all of the RPs share information about active sources.

This feature uses functionality that is already available on the Ruckus device but re-purposes it to provide the benefits desired as described in RFC 3446.