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Resource optimization and QoS for WDM optical networks

Kefei Wang, University of Nebraska - Lincoln


The advent of optical fiber, with its theoretically unlimited bandwidth, presents a good solution to the increasing demand for bandwidth imposed by new applications and services. Wavelength Division Multiplexing (WDM) is the most promising technology to increase the network capacity and is emerging as a reasonable and cost-effective technology to utilize the theoretical bandwidth of fibers. WDM can increase the capacity of fibers by first assigning incoming optical signals to specific frequencies within a designated frequency band and then multiplexing the resulting signals into one fiber. ^ Moreover, wavelength can be reused in different parts of WDM networks. The employment of this technology contributes to the increase in the number of sessions that can be supported. As such, these networks can provide a means to serve applications that individually or collectively require large amounts of bandwidth. An important class of services with such property is the class of multicast, or multipoint traffic [43], which requires the delivery of data from a source to a group of destinations. One of the goals of this research is to deal with multicast services in optical networks. We develop multicast tree construction algorithms for optical networks that take into account the optical network constraints, such as the power budget, wavelength collisions and wavelength continuity, as well as the cost and type of splitters and wavelength converters. ^ Since optical networks carry a large volume of data in transient, therefore, optical layer protection has gained a considerable attention in research community. A WDM network may fail due to the failure of any of its components. A link failure can be caused by a fiber cut or a failure of end components like a multiplexer/demultiplexer. A node can fail due to the failure of its switching fabric, or controllers. In either case, such a component failure will result in a failure of all the lightpaths that utilize that component. It may be noted that recovery at optical layer is much more desirable because restoration of optical layer is usually expected to take a time of the order of few milliseconds, compared to that of few seconds at higher protocol layers like the IP layer [42]. This research addresses the problem of Routing and Wavelength Assignment (RWA) for survivable networks with the objective of optimizing the needed wavelength links and the number of optical/electrical devices. ^ Harnessing the unprecedented bandwidth offered by WDM to meet the rapidly growing Internet traffic requires WDM networks to be optimized for IP traffic. More and more Internet applications are evolving from best-effort services toward integrated or differentiated services framework with QoS assurances. When QoS is taken into account, the selection of lightpaths is a problem in the optical network domain. We study the integrated traffic engineering approach for QoS in WDM networks and design algorithms optimize the utilization of network resources. ^ In this research, the overall objective is to investigate and develop methodologies to solve resources optimization and QoS problems in WDM optical networks. ^

Subject Area

Computer Science

Recommended Citation

Wang, Kefei, "Resource optimization and QoS for WDM optical networks" (2006). ETD collection for University of Nebraska - Lincoln. AAI3225887.