We consider an IP-over-WDM network in which network nodes employ optical crossconnects and IP routers. Nodes are connected by fibers to form a mesh topology. Any two IP routers in this network can be connected together by an all-optical wavelength-division multiplexing (WDM) channel, called a lightpath, and the collection of lightpaths that are set up form a virtual topology. In this paper, we concentrate on single fiber failures, since they are the predominant form of failures in optical networks. Since each lightpath is expected to operate at a rate of few gigabits per second, a fiber failure can cause a significant loss of bandwidth and revenue. Thus, the network designer must provide a fault-management technique that combats fiber failures. We consider two faultmanagement techniques in an IP-over-WDM network: 1) provide protection at the WDM layer (i.e., set up a backup lightpath for every primary lightpath) or 2) provide restoration at the IP layer (i.e., overprovision the network so that after a fiber failure, the network should still be able to carry all the traffic it was carrying before the fiber failure). We formulate these fault-management problems mathematically, develop heuristics to find efficient solutions in typical networks, and analyze their characteristics (e.g., maximum guaranteed network capacity in the event of a fiber failure and the recovery time) relative to each other.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.