Bin Wang (Advisor)
Doctor of Philosophy (PhD)
Wavelength division multiplexing (WDM) optical networks are widely viewed as the most appropriate choice for future Internet backbone with the potential to fulfill the ever-growing demands for bandwidth. WDM divides the enormous bandwidth of an optical fiber into many non-overlapping wavelength channels, each of which may operate at the rate of 10 Gigabit per second or higher. A failure in a network such as a cable cut may result in a tremendous loss of data. Therefore, survivability is a very important issue in WDM optical networks. The objective of this dissertation is to address the survivability provisioning problem in WDM optical networks under a scheduled traffic model and a sliding scheduled traffic model that we propose. In contrast to the conventional traffic models considered in communication networks such as static traffic model and dynamic random traffic model, the scheduled traffic model and the sliding scheduled traffic model are able to capture the traffic characteristics of applications that require capacity on a time-limited basis. They also give service providers more flexibility in provisioning the requested demands and a better opportunity to optimize the network resources. The survivability provisioning problem is to determine a pair of link-disjoint paths under the link failure model or a pair of SRLG-disjoint paths under the Shared Risk Link Group (SRLG) failure model, one working path and one protection path, for each demand in a given set of traffic demands with the objective of minimizing the total resources used by all traffic demands while 100% restorability is guaranteed against any single failure. To provision survivable service under the scheduled traffic model, we develop two sets of integer linear program (ILP) formulations for joint and non-joint optimizations using different protection schemes such as dedicated and shared path based protections. We also design a capacity provision matrix based Iterative Survivable Routing (ISR) algorithm with different demand scheduling policies to solve the survivable routing and wavelength assignment (RWA) problem. In addition, we extend the heuristic algorithm design from dealing with single link failure to single SRLG failure. The issue of survivability provisioning in WDM optical networks under the sliding scheduled traffic model has never been addressed by the research community. In the dissertation, we carry out the following tasks under this traffic model: (a) development of RWA ILP optimization formulations for dedicated and shared path based protection; (b) design and implementation of efficient heuristic algorithms for shared path based protection. Specifically, in the proposed heuristic algorithm, we introduce a demand time conflict reduction algorithm to minimize the time overlapping among a set of demands by properly placing a demand within its associated time window; and (c) extending the heuristic algorithm design under the single link failure model to the single SRLG failure model.
Department or Program
Department of Computer Science and Engineering
Year Degree Awarded
Copyright 2007, all rights reserved. This open access ETD is published by Wright State University and OhioLINK.