Shared protection in multicast optical networks

This paper investigates the problem of survivable multicasting in wavelength-division-multiplexing (WDM) optical mesh networks using optical-layer mixed-sharing protection. The term ldquomixed-sharingrdquo refers to that both the schemes of ldquoself-sharingrdquo and ldquocross-sharingrdquo are implemented to protect the multicast sessions. Each link on the primary tree(s) of a multicast session engrosses a wavelength channel. Under normal operation, the backup resources do not carry any traffic. So the backup resources of a multicast session may be shared by that of other sessions in the network. In this paper, we formulate an optimization model of the mixed-sharing protection for a batch of multicast sessions. We can obtain the optimal primary trees and their backup resources by solving the formulation. Simulation results show that the scheme of mixed-sharing can improve the performance of protection.