An efficient shared path protection based on quality of service in WDM networks.

With the explosive growth of the Internet in the past decade, survivability and high-bandwidth have become the most critical characteristics for networks. Determining the most efficient and reliable network configuration is a significant challenge in current optical network research. WDM (Wavelength Division Multiplexing) has become one of the most important features of optical networks because of its highly improved utilization of network capacity. The design of WDM networks can be analyzed from two perspectives: Network Design, and Routing & Wavelength Assignment (RWA). Network design includes physical topology design and configuration design. Routing and Wavelength Assignment (RWA) involves mapping lightpaths into the physical topology and assigning wavelength to these lightpaths. In this thesis, we concentrate on RWA, and propose a new formulation for dynamic lightpath allocations in fault-tolerant optical networks. We use WDM shared-path protection to achieve fault tolerance. Our formulation can accommodate three different qualities of service (QoS), each requiring a different amount of resources. We generate an efficient MILP formulation for dynamic lightpath allocation based on the QoS, and show through simulations, that it can be used for a practical-sized WDM networks. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2002 .H8. Source: Masters Abstracts International, Volume: 42-01, page: 0259. Adviser: Arunita Jaekel. Thesis (M.Sc.)--University of Windsor (Canada), 2003

Optimal Regenerator Placement for Dedicated Path Protection in Impairment-Aware WDM Networks

Building resilient Wavelength Division Multiplexed (WDM) optical networks is an important area of research. This thesis deals with the design of reliable WDM networks where physical layer impairments are taken into account. This research addresses both the regenerator placement problem (RPP) and the routing with regenerator problem (RRP) in impairment-aware WDM networks, using dedicated path protection. Both the problems have been tackled using linear Integer formulations which can be implemented, using a solver such as the CPLEX. For solving RPP, two solutions have been proposed - i) a formulation that gives optimal solutions which works only for small networks, and ii) a highly effective heuristic which given an optimal solution in 97.5 to 99% of cases for networks having a size up to 60 nodes

Heuristic for the design of fault tolerant logical topology.

Wavelength division multiplexing (WDM) in optical fiber networks is widely viewed as the savior for its potential to satisfy the huge bandwidth requirement of network users. Optical cross connect (OCX) in WDM network facilitates the switching of signal on any wavelength from any input port to any output port. As a result, it is possible to establish ligthpaths between any pair of nodes. The set of lightpaths established over fiber links defines logical topology. In our thesis, we proposed a heuristic approach for the design of fault tolerant logical topology. Our design approach generalizes the design protection concept and enforces wavelength continuity constraint in a multi-hop optical network. In our work, we first designed logical topology for fault free state of the network. We, then, added additional lightpaths for each single link failure scenario. Numerical results clearly show that our approach outperforms Shared path protection and Dedicated path protection. Our simulation result shows that our approach is feasible for large networks. (Abstract shortened by UMI.) Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2005 .S24. Source: Masters Abstracts International, Volume: 44-03, page: 1413. Thesis (M.Sc.)--University of Windsor (Canada), 2005

WDM optical network: Efficient techniques for fault-tolerant logic topology design

The rapid increase of bandwidth intensive applications has created an unprecedented demand for bandwidth on the Internet. With recent advances in optical technologies, especially the development of wavelength division multiplexing (WDM) techniques, the amount of raw bandwidth available on the fibre links has increased by several orders of magnitude. Due to the large volume of traffic these optical networks carry, there is one very important issue---design of robust networks that can survive faults. Two common mechanisms to protect against the network failure: one is protection and another is restoration. My research focuses on studying the efficient techniques for fault-tolerant logical topology design for the WDM optical network. In my research, the goal is to determine a topology that accommodates the entire traffic flow and provides protection against any single fiber failure. I solve the problem by formulating the logical topology design problem as a MILP optimization problem, which generates the optimum logical topology and the optimum traffic routing scheme. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2004 .S54. Source: Masters Abstracts International, Volume: 43-01, page: 0244. Adviser: Arunita Jaekel. Thesis (M.Sc.)--University of Windsor (Canada), 2004

A heuristic for WDM path protection.

Optical fibers and Wavelength Division Multiplexing (WDM) are being researched as well as commercially deployed as technologies that can satisfy the bandwidth requirements of the Internet today and the foreseeable future. Since optical resources are expensive, we need to develop network design mechanisms, which can achieve an efficient utilization of network resources in a reasonable computational time. In WDM networks, the failure of a single fiber link may cause very large data loss if the traffic is not rerouted quickly. Therefore, the survivability of optical connections has become a very important issue for WDM network design. In this thesis, we present a heuristic method to determine the logical topology and routing scheme with WDM shared-path protection. In this protection scheme, a primary path and a backup path are determined for each optical connection. The simulations of our heuristic show that it is simple and efficient, and can be used for designing fault-tolerant logical topologies for practical-sized WDM networks. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2003 .H68. Source: Masters Abstracts International, Volume: 42-02, page: 0615. Thesis (M.Sc.)--University of Windsor (Canada), 2003

Dimensioning of an European backbone network in OPNET WDM Guru

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