Virtual Topology Design for Traffic Grooming in WDM Networks

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Title: Virtual Topology Design for Traffic Grooming in WDM Networks
Author: Dutta, Rudra
Advisors: George N. Rouskas, Chair
Harry G. Perros, Member
Carla D. Savage, Member
Wenke Lee, Member
Abstract: Wavelength division multiplexing (WDM) in optical fiber networks iswidely viewed as the technology with the potential to satisfy theever-increasing bandwidth needs of network users effectively and on asustained basis.In WDM networks, nodes are equipped with optical cross-connects(OXCs), devices which can optically switch a signal on any givenwavelength from any input port to any output port.This makes it possible to establish light paths between any pair of network nodes.A lightpath is a clear channel in which the signal remainsin optical form throughout the physical path between the two endnodes.The set of lightpaths established over the fiberlinks defines a .Consequently, the problem arises of designing virtual topologies tooptimize a performance measure of interest for a set of trafficdemands. With the deployment of commercial WDM systems, it has become apparentthat the cost of network components, especially line terminatingequipment (LTE) is the dominant cost in building optical networks, andis a more meaningful metric to optimize than, say, the number ofwavelengths.Furthermore, since the data rates at which each individual wavelengthoperates continue to increase (to OC-192 and beyond), it becomes clearthat a number of independent traffic components must be multiplexed inorder to efficiently utilize the wavelength capacity.These observations give rise to the concept of, which refers to the techniques used to combine lower speed componentsonto available wavelengths in order to meet network design goals suchas cost minimization. Traffic grooming is a hard problem in generalwhich remains computationally intractable even for simple networks. We consider the problem of traffic grooming in ring, star andtree topologies. We provide theoretical results regarding achievabilitybounds for these networks as well as practical frameworks to obtainincreasingly better feasible solutions with the expenditure of morecomputational power.
Date: 2001-08-06
Degree: PhD
Discipline: Computer Science
URI: http://www.lib.ncsu.edu/resolver/1840.16/5466


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