Switching/merging node placement in survivable optical networks with SSP

Shared Segment Protection (SSP) has been proved to serve as a viable approach in achieving better flexibility and capacity efficiency than that by the conventional link and path shared protection. The superiority of SSP is nonetheless at the expense of taking more signaling efforts and requiring higher hardware precision in switching and merging restoration optical flows at core nodes. Therefore, the switching and merging capability of a network node is a kind of network resource that should be subject to manipulative planning. This paper investigates the performance impact by allocating the switching/merging (S/M) capable nodes in optical networks employing SSP. Two novel performance metrics, Average Increase in Blocking Probability (AIBP) and Average Increase of Total Cost (AITC), are devised to define the importance of being S/M capable for each node. A novel recursive algorithm is developed to evaluate the proposed performance metrics, in which both a brute force method and an enhanced method for reducing computation complexity are discussed. Simulation is conducted on two network topologies to verify the proposed approaches in evaluating the two performance metrics.