Bandwidth Constrained IP Multicast Traffic Engineering Without MPLS Overlay

摘要

Existing multicast traffic engineering (TE) solutions tend to use explicit routing through MPLS tunnels. In this paper we shift away from this overlay approach and address the bandwidth constrained IP multicast TE directly based on link state IGP routing protocols. The objective is that, through plain PIM-SM shortest path routing with optimized Multi-topology IS-IS (M-ISIS) link weights, the resulting multicast trees are geared towards minimal consumption of bandwidth resources. We apply Genetic Algorithms (GA) to the calculation of optimized M-ISIS link weights that specifically cater for engineered PIM-SM routing with bandwidth guarantees. Our evaluation results show that GA-based multicast traffic engineering consumes significantly less bandwidth resources in comparison with conventional IP approaches, while it also exhibits higher capability of eliminating/alleviating link congestion. The key contribution is a methodology for engineering multicast flows in a pure IP environment, without MPLS explicit routing that potentially suffers from scalability problems in terms of LSP maintenance.