Efficient shared segment protection in optical networks

This thesis introduces a new shared segment protection scheme that ensures both node and link protection in an efficient manner in terms of cost. Although the segment protection scheme exhibits an interesting compromise between link and path protection schemes and attempts to encompass all their advantages, it has been much less explored than the other protection approaches. The proposed work investigates two different Shared Segment Protection (SSP) schemes: Basic Shared Segment Protection (BSSP) and a new segment protection, called Shared Segment Protection with segment Overlap (SSPO). For both BSSP and SSPO schemes, we propose two novel efficient and scalable ILP formulations, based on a column generation mathematical modeling. SSPO offers more advantages over BSSP as it ensures both node and link protections, in addition to shorter delays. It is not necessarily more expensive while BSSP ensures only link protection. Indeed, depending on the network topology and the traffic instances, it can be shown that neither of the two SSP schemes is dominant in terms of cost. The mathematical models have been solved using column generation techniques. Simulations have been conducted to validate the two segment protection models and to evaluate the performance of the two segment protection schemes under different traffic scenarios. In addition, we have estimated when an additional cost (and how much) is needed in order to ensure node protection