Dual-homing based scalable partial multicast protection
In this paper, we propose a scalable multicast protection scheme based on a dual-homing architecture where each destination host is connected to two edge routers. Under such an architecture, there are two paths from the source of a multicast session to each destination host, which provides a certain level of protection for the data traffic from the source to the destination host. The protection level varies from 0 percent to 100 percent against a single link failure, depending on the number of shared links between these two paths. The major advantage of the proposed scheme lies in its scalability due to the fact that the protection is provided by constructing a dual-homing architecture at the access network while keeping the routing protocols in the core network unchanged. The selection of dual edge routers plays an important role in enhancing the protection level. Two problems arise for the proposed dual-homing partial multicast protection scheme. One is to calculate the survivability from the source to any pair of edge routers. The other is to assign a pair of edge routers for each destination host such that the total survivability is maximized for the multicast session subject to the port number constraint of each edge router. We propose an optimal algorithm to solve the first problem. We prove the decision version of the second problem is NP-complete and propose two heuristic algorithms to solve it. Simulation results show that the proposed heuristic algorithms achieve performance close to the calculated lower bound.
multicast protection networks survivability np-completeness complexity