QoS multicast routing with delay constraints

Proliferation of group-based real-time applications, such as online games and video conferencing has motivated research into QoS multicast routing. These types of applications require consideration of both source-to-destination delay (i.e., packet delay from the source to all destinations) and inter-destination delay variation (i.e., the difference in packet delay from the source to different destinations) constraints. In this paper we formulate a new combined problem for delay partitioning and multicast routing with source-to-destination delay and inter-destination delay variation constraints in a QoS framework, where a delay dependent cost function is associated with each network link. After identifying the problem as NP-complete, we introduce a Genetic Algorithm (GA) based algorithm that computes a source-based multicast tree which satisfies both constraints with near-optimal cost. We compare different GA schemes using different selection operators and find that the combination of Steady State GA and Remainder Stochastic Sampling selection operator works best for our problem. Simulation results also show that our GA heuristic consistently perfornis better than several other simple heuristics.