Distributed network control for establishing reliability-constrained least-cost lightpaths in WDM Mesh networks

Abstract

The trend in the development of intelligent optical networks has recently started moving towards a unified solution, to support voice, data, and various multimedia services. In this scenario different applications/end users may need different levels of fault-tolerance and differ in how much they are willing to pay for the service they get. A control scheme which is used to set up and tear down lightpaths, should not only be fast and efficient, but also be scalable. In addition, it should also try to minimize the number of blocked connections while satisfying the requested level of fault-tolerance. In this work we choose reliability of a connection as a quality of service (QoS) parameter to denote different levels of fault-tolerance. We prove that reliability-constrained least-cost (RCLC) routing problem is NP-complete and propose a distributed control scheme based on preferred link approach for establishing RCLC lightpaths. We prove the correctness of the proposed scheme and show that the scheme is flexible in that a variety of heuristics can be employed to order the neighboring links of any given node. Four heuristics are proposed and their performance is studied through extensive simulation experiments on wavelength selective networks for different network configurations. The simulation results show that our heuristics provide better performance in terms of average call acceptance rate, average path cost, average routing distance, and average connection setup time; when the connection requests with different reliability requirements arrive to and depart from the network randomly. Furthermore, if a network service provider feels that it can earn more revenue by admitting more number of calls with reliability requirements, it can do so by manipulating the parameters of our scheme, such as the maximum number of preferred links used at each node. © 2007 Elsevier B.V. All rights reserved.