Cross-Layer Approach to Survivable DWDM Network Design

Abstract

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 work, we apply cross-layer techniques, previously successfully applied to the impairment-constrained routing and wavelength assignment problem [IEEE J. Sel. Areas Commun., vol. 26, p. 32, 2008], 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 survivability over non-cross-layer algorithms by decreasing both the blocking probability and the vulnerability of the network to failures. Our mechanisms are evaluated with extensive simulations for a realistic regional-sized network. The cross-layer algorithms are computationally intensive, and to alleviate this issue we propose two new compound restoration algorithms as well as two novel quality-of-transmission-aware protection schemes that exhibit low blocking probability and have a moderate vulnerability ratio and time complexity.