PXT-based path protection for multicast sessions in WDM networks

Due to the huge bandwidth provided by an optical fiber, a fiber cut in an optical network will disrupt a large number of communication sessions. Therefore, it is important to protect both unicast and multicast traffic against link failures. Link failures have more serious impact on multicast sessions than unicast ones since multiple destinations may be affected by a link failure on the multicast tree. To protect multicast sessions efficiently, researchers have proposed path-based and segment-based protection schemes. However, these schemes require long restoration time. While p-cycle-based link protection schemes have short restoration time, they are not capacity efficient. In this paper, we address the dilemma by proposing a PXT-based path protection scheme that provides both short restoration time and high capacity efficiency. The basic idea is to use pre-cross-connected PXTs to protect individual destinations on multicast trees. Simulations results show that our scheme is significantly more efficient than a p-cycle-based link protection scheme.