Logical Topology Design for IP-over-WDM Networks: A Hybrid Approach for Minimum Protection Capacity

The problem of designing high capacity and high bit rate IP-over-WDM networks, which can provide uninterrupted service in the presence of network equipment failures, continues to attract significant interest from the research community. An IP-over-WDM network implements Internet Protocol (IP) directly over physical WDM network by establishing lightpaths using IP routers, optical crossconnects (OXC) and optical fibers. Generally an optical fiber carries several lightpaths and all of them get disconnected, if the fiber carrying them fails. Such failures can quickly impact the performance of the entire network. If IP routers can find paths to all the nodes in the network, then the network can continue to provide service without significant performance degradation. This can be achieved by reserving network resources (protection) or provisioning the network with some additional capacity (restoration). Such networks are usually called survivable networks. In this paper, we propose four algorithms based on SMART framework proposed by Kurant and Thiran, and a hybrid approach by Shenai and Sivalingam. The algorithms use a combination of protection and restoration mechanisms to make IP-over-WDM networks survivable such that the protection capacity required is not significant.