Optimal capacity placement for path restoration in STM or ATM mesh-survivable networks

The total transmission rapacity required by a transport network to satisfy demand and protect it from failures contributes significantly to its cost, especially in long-haul networks. Previously, the spare capacity of a network with a given set of working span sizes has been optimized to facilitate span restoration [11], [12], Path restorable networks can, however, be even more efficient by defining the restoration problem from an end to end rerouting viewpoint, We pro vide a method for capacity optimization of path-restorable networks which is applicable to both synchronous transfer mode (STM) and asynchronous transfer mode (ATM) virtual path (VP)-based restoration, Lower bounds on spare capacity requirements in span-and path-restorable networks are first compared, followed by an integer program formulation based an how constraints which solves the spare and/or working capacity placement problem in either spanor path-restorable networks. The benefits of path and span restoration, and of jointly optimizing working path routing and spare capacity placement, are then analyzed.