| The performance of current optical networks is inherently limited by the speed of electronic components, and especially the electronic switches; a new generation of optical networks, referred to as all-optical networks, overcome this limitation by switching data entirely optically using all-optical crossconnects (OXCs). However, all-optical networks are prone to phenomena that are unknown to current optical networks. For instance, OXCs are subject to optical leaks, resulting in unwanted components called node crosstalk being added to transmitted signals. Node crosstalk is propagated over long paths without any signal regeneration.; We study the interplay between nonlinear fiber and node crosstalk signals over long distance as a source of Quality of Service (QoS) degradation, measured in terms of bit-error rate (BER). We present a crosstalk model for all-optical networks and give exact expressions for the performance degradation resulting from the joint propagation of a signal and node crosstalk in large networks. Realizing that crosstalk can be a serious impairment for proper network operation, we propose to mitigate physical layer impact (including node crosstalk) at call admission time using specifically designed QoS-aware Routing and Wavelength Assignment (RWA) algorithms (a network-layer technique). Our new RWA algorithms choose a route and a wavelength for incoming calls in all-optical networks (viewed as circuit-switched networks) depending on the physical-layer state, making RWA algorithms and all-optical networks design a cross-layer issue.; We show that our new RWA algorithms outperform traditional RWA algorithms while exhibiting additional interesting properties, such as enhancing the fairness among the users in the network. Our RWA algorithms are evaluated with simulations on realistic large-scale metropolitan and regional network topologies. To decrease the time to evaluate QoS-aware RWA algorithms, we also present an analytical technique to evaluate the performance of a class of RWA algorithms incorporating multiple physical layer impairments including node crosstalk. Our analytical technique is shown by simulation on various network topologies to model accurately all-optical network behavior. |
