A novel shared segment protection method for guaranteed recovery time

Shared segment protection (SSP), compared to shared path protection (SPP) or shared link protection (SLP), provides an optimal protection configuration, since SSP can increase the number of connections sharing the same protection segments and can reduce the restoration time in case of single link failure. This paper provides a thorough study on SSP under the GMPLS-based recovery framework, where an effective survivable routing algorithm for SSP is proposed, called shared segment protection (SSP) algorithm. The main advantage of the SSP algorithm is to reduce the high computation complexity in solving the ILP formulation first introduced in P-H. Ho et al., (2004). With an efficient iterative approach the design space is significantly reduced by excluding all the links that result intolerably long routes. The tradeoff between the price (i.e., cost representing the amount of resources, and the blocking probability) and the restoration time is extensively studied by simulations on three networks with highly dynamic traffic. It is demonstrated that the SSP algorithm can be a powerful solution in the GMPLS-based recovery with a stringent delay upper bound for achieving high availability and restorability of the transport services. The comparison among the three protection types further verifies that SSP can yield significant advantages over SPP and SLP.