VND-CS: A Variable Neighborhood Descent Algorithm for Core Selection Problem in Multicast Routing Protocol

Abstract

Core Selection CS problem consists in choosing an optimal multicast router in the network as the root of the shared path multicast tree (SPT). The choice of this designated router (refer to as the “Rendezvous Point RP” in PIM-SM protocol and the “core” in CBT protocol) is the main problem concerning multicast tree construction; this choice influences multicast routing tree structure, and therefore influences performances of both multicast session and routing scheme. The determination of a best position of the Rendezvous Point is an NP complete problem: it needs to be solved with a heuristic algorithm. In this paper we propose a new Core Selection CS algorithm based on Variable Neighborhood Descent algorithm, based on a systematic neighborhood changing. VND-CS algorithm selects the core router by considering both cost and delay functions. Simulation results show that good performance is achieved in terms of multicast cost, end-to-end delay and tree construction delay.