Anycast Rendevous Point (RP) mechanism using Protocol Independent Multicast (PIM) and Multicast Source Discovery Protocol (MSDP)

Anycast RP relaxes an important constraint in PIM-SM, namely, that there can be only one group to RP mapping can be active at any time. The single mapping property has several implications, including traffic concentration, lack of scalable register decapsulation (when using the shared tree), slow convergence when an active RP fails, possible sub-optimal forwarding of multicast packets, and distant RP dependencies. These properties of PIM-SM have been demonstrated in native continental or inter-continental scale multicast deployments. As a result, it is clear that ISP backbones require a mechanism that allows definition of multiple active RPs per group in a single PIM-SM domain. Further, any such mechanism should also address the issues addressed above.