Scalable QoS multicast provisioning in Diff-Serv-supported MPLS networks

IP multicast suffers from scalability problems as the number of concurrent active multicast groups increases, since it requires a router to keep a forwarding state for every multicast tree passing through it. In QoS multicast provisioning, the problem is exacerbated, since not only the forwarding state but also the resource requirement of a multicast group must be kept at the router. To provide scalable QoS multicast support, in this paper, we propose a novel architecture, called Aggregated QoS Multicast (AQoSM). Using the concept of aggregated multicast, AQoSM can support QoS multicast scalably and efficiently in DiffServ-supported MPLS networks. In this paper, we develop the framework for the architecture and provide a feasibility check from an implementation point of view. The architecture is flexible and can be customized to the needs and the existing protocols of a domain. Our simulations indicate that the architecture performs well in several common scenarios. It achieves smaller blocking of users with strong QoS requirements because of its load balancing capability. It also achieves up to 85% reduction in state with a modest 10% of bandwidth overhead.