A distributed bandwidth-guaranteed routing algorithm for point-to-multipoint VPLS virtual connections

Virtual private LAN services (VPLS) is a new layer 2 (L2) virtual private network (VPN), which allows connection of multipoint customers at the same time. Multi-protocol label switching (MPLS) technology is the most popular candidate for implementing VPLS because it supports traffic engineering (TE) functionality over the established label switching paths (LSP). However, MPLS´s TE support is provided over point-to-point (P2P) LSPs. The functionality and signaling of point to multipoint (P2MP) LSPs are not supported in existing MPLS architecture. In this paper, we propose a new on line distributed routing algorithm for supporting QoS bandwidth flow guarantees. The algorithm provides TE functionality over the P2MP VPLS connections in the core MPLS networks. The on-line distributed routing algorithm maximizes the number of admitted requests by avoiding the critical links of other source-destinations sets. The critical links are identified based on the number of times the link is used to route the source-destinations set traffic and the load over the links. The algorithm does not assume any a priori knowledge of the network traffic. The proposed algorithm performance is compared to some existing algorithms such as the widest shortest path (WSP) and the Plotkin algorithms. It shows that it outperforms both algorithms by having lower blocking probability.