GRASP-BSMA: A fast algorithm for delay constrained multicast routing

Constrained minimum Steiner tree (CMST) problem is a key issue in multicast routing with quality of service (QoS) support. Many heuristics have been developed to solve this NP-complete problem. In recent years, some interesting work has been done to use the greedy randomized adaptive search procedure (GRASP) to solve this problem. While it helps to achieve very high success ratios of finding optimal solutions on networks of small or medium sizes (less than 100 nodes), a high computation time is also required, usually in the range of tens of seconds. Considering a normal call admission time is expected to be in the range of tens or hundreds of milliseconds and network sizes may become much larger, it is worth developing algorithms that can run faster while keeping the tree cost at an acceptable level. In this paper, an algorithm called GRASP-BSMA is proposed for such purpose. By using an efficient procedure to construct the initial feasible solution, together with the best implementation of the bounded shortest multicast algorithm (BSMA), the proposed algorithm well meets the expectations.