Establishing multicast communications in MPLS-capable networks is an
essential requirement for a wide-scale deployment of MPLS in the
Internet. This paper outlines a framework for the setup of a
MultiPoint-to-MultiPoint (MP2MP) Label Switched Path (LSP) for establishing uni-directional multicast shared trees. The presented framework is intended for multicast applications within a single autonomous domain and can be extended to cover inter-domain multicast sessions.
We propose the use of one (or more) control points in the network called Rendez-vous Points (RP) in a manner similar to PIM-SM shared trees. Senders of the multicast session have to register with the RP and establish unicast LSPs with the RP. Receivers who join the session have to send their join requests to the RP which acts as a root (and the sender) of a one-to-many tree by establishing a Point-to-MultiPoint (P2MP) LSP between the RP and the receiver. This architecture utilizes more than one RP to implement RP failure recovery, to provide load balancing within the domain, and to enable the extension of this framework to multiple domains by establishing LSPs between RPs in different domains. This architecture also has the advantage of using existing MPLS techniques and existing routing protocols and requires only the addition of more management capabilities at the RPs. The paper explains the framework in details and provides an example on how to set the LSP on a given topology.
We also refer to some preliminary simulation results testing the scalability of the architecture in comparison with traditional multicast routing.