Minimizing Multicast Routing Delay in Multiple Multicast Trees With Shared Links for Smart Grid

Multicast routing is essential in many smart grid applications, e.g., wide area control, wide area protection, and wide area monitoring, for low-latency communications. Coexistence of multiple smart grid applications requires that the communication network accommodate many multicast communications simultaneously with low latency. This requirement leads to congestion on some shared links in multiple multicast trees and consequently deteriorated multicast delay performance. While minimizing multicast routing delay has been investigated for a single multicast group, there is a lack of a general framework to deal with multicast routing delay in multiple multicast trees with shared links for smart grid. To address this issue, a systematic approach, namely betweenness centrality to bandwidth ratio tree (BCBT) approach, is presented in this paper. It formulates the multicast delay problem as a constrained BCBT optimization problem. It uses the shortest path tree (SPT) multicast routing under light traffic, but switches to BCBT multicast routing when the multicast links get congested so that the SPT congestion is alleviated. A greedy algorithm with heuristics is developed to solve the BCBT optimization problem. Simulations are conducted to demonstrate the BCBT approach.