Impact of Resource Sharability on Dual Failure Restorability in Optical Mesh Networks

Protection capacity re-provisioning mitigates the impact of double-link failures by provisioning new capacity for unprotected demands in a network designed to achieve 100% restorability under singlelink failures. We study the performance of re-provisioning in networks under various resource sharing degrees. Intuitively, the lower is the sharability degree of resources the smaller is the number of unprotected connections resulting after the recovery from a failure. However, we show in this paper that limited resource sharability also implies limited flexibility for the network in finding capacity for unprotected demands after failures; which accordingly limits the capability of re-provisioning schemes in improving the network restorability. We further study the performance of different re-provisioning algorithms under distributed control and we show that contentions severely impact the restorability performance. Finally, we propose a simple mechanism to mitigate the effects of contentions.