Minimum CAPEX design of segment p-cycles with full node protection

Shared-segment protection offers a good compromise between shared link and path protection, i.e., has the features of high resource efficiency and short protection-switching time. In this paper, we further investigate segment protection along two directions, (i) within the context of pre-configured pre-cross connected protection schemes (i.e., with p-cycles), and (ii) with the evaluation of the additional required CAPEX cost in order to ensure node protection in addition to protection against single link failures. We propose a scalable model which takes advantage of large scale optimization tools for its solution, and compare the best trade-off between regular segment protection (segment p-Cycles) and enhanced segment protection (with node protection) (Np-cycles) within the p-cycle protection framework. Numerical results show that protection against single node failures can be ensured with about 3% extra CAPEX and no more than 3% extra spare capacity, throughout an adaptation of segment p-cycles. This suggests that segment Np-cycles constitute an attractive protection scheme for protection against single node or link failures.