A Solution for IP Multicast VPNs based on Virtual Routers

Though the combination of IP multicast and VPN technology has realized efficient point-to-multipoint delivery and solved large-scale inter-domain multicast currently, it suffers from scalability problem on backbone with the rapid growth of the multicast services. This paper puts emphasis on studying L3 VPN multicast and proposes a solution for IP multicast VPN based on virtual routers. The key idea is that all multicast traffic from the same VR are forced to share the same one delivery tree by deploying source specific tree or shared tree with the VR acting as source or RP. It details this solution according to process in local customer sites, method of establishing multicast distribution trees in service provider networks and forwarding flow of multicast data packets. The analysis shows that the mechanism can effectively reduce the router´s multicast states on backbone on tradeoff between scalability and flexibility of router optimization, and ensure the bandwidth resource utilization