Patent ID: 8619774

Claim:
A method of providing multicast messages within a virtual private network across a data communication network, the method comprising the computer-implemented steps of: receiving a multicast join message at a first node on a first autonomous system; adding to the multicast join message a next hop address, an address of a router to which the multicast join message is to be sent, and a multicast distribution tunnel identifier; forwarding, using the multicast distribution tunnel identifier, the multicast join message to the next hop address of a second node on a second autonomous system; using the multicast distribution tunnel identifier, forwarding the multicast join message from the second autonomous system to the router on a third autonomous system; wherein the virtual private network comprises a multicast distribution tunnel that spans the first, the second and the third autonomous systems; wherein adding the address of the router to which the multicast join message is to be sent further comprises the step of adding to the multicast join message a Route Distinguisher for a multicast group, wherein the Route Distinguisher is to be used by an Autonomous System Boundary Router on the second autonomous system to identify another next hop address; wherein the Route Distinguisher is different from the multicast distribution tunnel identifier; wherein the method is performed by one or more processors.