Multi Protocol Label Switching (MPLS) [1] has been widely deployed in both service provider and enterprise networks alike. The main drivers for deploying an MPLS based forwarding mechanism for IPv4 include Layer 2 [2] and Layer 3 [3] Virtual Private Networks, and Traffic Engineering [4] and Fast Reroute [5].

The protocol transparency of MPLS infrastructures can also be leveraged, with minimal core impact, to provide IPv6 services. MPLS 6PE (Provider Edge) [6] has proven to be a popular and widely deployed architecture for forwarding IPv6 unicast packets across an IPv4 / MPLS enabled core infrastructure.

Along with unicast connectivity, today?s networks are more and more often required to support IP multicast services as well. It is estimated that new types of end-user applications will significantly increase the need for deploying IPv4 and IPv6 multicast solutions.

This paper discusses two possible architecture options for deploying IPv6 multicast [7] forwarding across an already existing IPv4 / MPLS enabled core infrastructure. In both of the scenarios, IPv6 unicast packets are transported through an MPLS 6PE solution.