Quorumcast routing by multispace search

We present a multispace search algorithm, MUSQ, for the quorumcast routing problem. We first prune the candidate set to reduce the original search space. Some of the unqualified links for the optimal tree are removed from the network. Then a multispace search algorithm is used to solve the quorumcast routing problem. By altering the original objective function, the original problem instance is transformed into a series of gradually more simplified problem instances with smoother terrain surfaces. A local search algorithm is used to solve each problem instance, from the simplest structure to the original structure, and the solutions of the more simplified problem instances are used to guide the search of more complicated ones. Experimental results showed that this new method improved the performance of the existing heuristic algorithms.