Scalable Multicast Provisioning in DiffServ with MPLS Labeling

Abstract

The phenomenal growth of multimedia applications imposes scalable and efficient network support. The DiffServ and MPLS architectures were developed to provide QoS. The combination of both architectures presents a very attractive strategy to backbone network providers. However, integrating native IP multicasting with MPLS supports DiffServ is a quite comple issue. Major problems are: the lack of labels in MPLS networks, the core routers simplicity in DiffServ and the multicast state scalability problems, since it requires routers to keep a forwarding state for every multicast tree passing through it. In addition, the number of states grows with the number of groups. Under such circumstance, we propose an hybrid label aggregation algorithm in order to solve multicast scalability problem and provide a solution for multicast in MPLS support DiffServ. In the proposed scheme, one label is assigned per multicast groups (logical aggregation) and different multicast groups sharing the same output interface in a router are aggregated locally (physical aggregation). Also, in order to support the proposed algorithm, we propose a separate treatment and labels space (prime numbers range) for multicast traffic. The proposed solution allows consuming fewer labels, reducing the forwarding table and consequently the total packet processing delay.