Explicit routing in MPLS is utilized in traffic engineering to maximize the operational network performance and to provide quality of service (QoS). However, difficulties arise while integrating native IP multicasting with MPLS traffic engineering, such as point-to-multipoint or multipoint-to-multipoint LSP layout design and traffic aggregation. In this paper, we have proposed an edge router multicasting (ERM) scheme by limiting the branching point of the multicast delivery tree to only the edges of MPLS domains. As a result, multicast LSP setups, multicast flow assignments, and multicast traffic aggregation are reduced to unicast problems. We have studied two types of ERM routing protocols in the paper. The first approach is based on modifications to the existing multicast protocols, while the second approach applies a Steiner tree-based heuristic routing algorithm in the edge router multicasting environment. The simulation results demonstrate that the ERM scheme based on Steiner tree heuristic can provide near-optimal performance. The results also demonstrate that ERM provides a traffic engineering friendly approach without sacrificing the benefits of native IP multicasting.
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