The new shortest best path tree (SBPT) algorithm for dynamic multicast trees

This paper presents the new shortest best path tree (SBPT) algorithm for multicast trees. The SBPT algorithm establishes and maintains dynamic multicast trees which maximize the bandwidth to be shared by multiple receivers and simultaneously guarantee the shortest paths for each receiver node. The SBPT algorithm is a distributed algorithm with cost in the same order as the sum of the shortest path tree (SPT) and Greedy algorithms. The SBPT algorithm reduces bandwidth consumption by utilizing partial paths already established for other multicast receiver nodes. The SBPT algorithm finds such partial paths when multiple shortest paths exist. Simulation experiments comparing the SBPT and SPT algorithms show that the SBPT algorithm reduces bandwidth consumption by 5% to 17% when node utilization is greater than approximately 25% and always achieves the same shortest path lengths.