Designing a survivable IP-over-WDM network

In this paper we investigate the problem of designing a survivable IP over WDM networks. We present a novel integrated protection scheme to dynamically allocate restorable bandwidth guaranteed path. Restoration implies that a flow of data is successfully routed if both an active path and another alternate link-disjoint path are setup at the same time. The new scheme takes advantage of the recent development in MPLS/MP(lambda) S to provide integrated end-to-end survivability, and incorporates network state information (such as the cost information in physical links, the bandwidth usage on each lightpath, and intermediate router forwarding speed) into protection path allocation. We design a survivable logical topology on top of the underlying physical connectivity that connects IP routers. Unlike the conventional approach for designing a static logical topology where the traffic demand is known a priori, we dynamically construct the logical connections between IP routers. This approach leads to a new QoS routing problem where it is necessary to dynamically route both an active path and a backup path in order to satisfy a request to set-up a restorable bandwidth guaranteed paths. Simultaneously establishing backup paths ensures fast restoration by eliminating path computation and path set-up signaling delays.