Cross-Layer Approach to Resilient All-Optical Network Design Open Access
Downloadable ContentDownload PDF
All-optical networks, in which the electrical regeneration bottlenecks are removed, are seen as the next-generation backbone networks. Any link failure in these high speed environments, if not dealt with promptly, is catastrophic and can cause the loss of gigabits of data. While techniques to improve the survivability of optical networks are now well-established, such is not the case with all-optical networks. In these environments, the absence of regeneration implies that physical impairments accumulate over long paths. So-called cross-layer techniques mitigate the physical impairments' impact on the network layer performance. In this dissertation new cross-layer approaches are applied to the problem of improving the survivability of all-optical networks facing link failures. To the best of our knowledge, cross-layer survivability of all-optical networks has never been studied before. We present algorithms that improve the network resilience over non cross-layer algorithms by decreasing both the blocking probability and the vulnerability of the network to failures. These mechanisms are evaluated with intensive simulations for a realistic regional-sized network.The cross-layer algorithms are computationally intensive, and to alleviate this issue, two new compound restoration algorithms as well as two novel Quality of Transmission aware protection schemes are proposed that exhibit low blocking probability and have moderate vulnerability ratio and time complexity.Protection Cycle (p-Cycle) design is shown here to be a desirable approach to resiliency in all-optical networks. High recovery speed and efficiency are two well-known aspects of this approach. One other important performance metric that has been neglected in the past is its ability to recover from a failure in all-optical networks. In this dissertation we investigate the impact of different choices in p-Cycle selection on the network resilience. We also provide a new ILP formulation designed for all-optical networks that tries to optimize the network performance both in terms of blocking probability and Vulnerability Ratio. Furthermore we propose a new approach to provide multiple classes of protection in all-optical networks using p-Cycles. This approach is based on cross-connect preconfiguration for protection paths; for some links we allow only provisioning the protection path without preconfiguring the crossconnects. The advantage of this approach is that it is able to greatly increase the network resilience as well as providing the network operator with more options in meeting the protection demand of different traffics in the network. We also provide a new ILP formulation that achieves this goal.