An efficient and easily deployable QoS-based routing scheme for online Internet multicasting

With the advent of multimedia applications, the support of online multicasting with quality of service guarantees has gained considerable attention in the field of communication networks and distributed systems. Online multicasting requires the support of online join and leave operations. In this paper, a new Simple and Efficient Low-cost Delay-bounded Online Multicasting (SELDOM) heuristic is proposed. SELDOM is particularly tailored to networks in which group membership changes frequently. SELDOM supports two modes of operations: non-rearrangeable and rearrangeable. The scheme handles join requests dynamically by determining the least-cost path which satisfies the required delay-bounds to which the new group member is to be attached. To handle a leave request, the scheme seeks to limit the number of rearrangements required in order to reduce the disturbance such a request may cause to current group members. The worst case time complexity of SELDOM is O(n²). An important research contribution of this work shows that if any non-rearrangeable multicast heuristic uses a path other than the least-delay path to add a node to the multicast tree, then the resulting multicast tree can have cycles or nodes with two incoming paths. A simulation-based comparison between non-rearrangeable and rearrangeable online multicast trees is also presented.