Traffic grooming in IP over WDM optical networks
Fang, Jing (2004) Traffic grooming in IP over WDM optical networks. PhD thesis, Iowa State University.
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Telecommunication networks evolve as technology advances and society changes. Optical communications employing Wavelength Division Multiplexing (WDM) has become the dominant technology for use in backbone networks. As IP gains in popularity, the traffic pattern in carrier networks is increasingly becoming data centric. This has led to a change in the network infrastructure and many researchers believe that networks are evolving towards the slim two-layer model of IP over WDM. In this dissertation, we address several fundamental issues of the grooming network design - the process of multiplexing, demultiplexing and switching lower rate traffic stream onto and off of higher capacity wavelengths, in the context of IP over WDM. We explain how wavelength continuity constraint and wavelength usage constraint affect network performance. Based on our research, we infer that, in practical WDM networks with wavelength usage constraint, increasing the total number of available wavelengths in a fiber is an attractive alternative to employing wavelength conversion. We investigate traffic grooming performed in IP layer, where the sub-wavelength level IP packets are grouped together in electrical domain before they are sent to the WDM layer. We study IP traffic grooming problem with the objective to minimize the number of transmitters and receivers needed in the WDM layer. We propose three routing strategies for allocating dynamic traffic requests and evaluate their blocking performance. The third issue addressed in this dissertation is IP traffic grooming in a recently proposed architecture called light trails. We define the light trail design problem and identify the minimum number of light trails to carry the given traffic demand. We formulate an ILP and develop two heuristic approaches for obtaining fast and near-optimal solutions in large networks. We finally address the issue of fault management in grooming networks. We study shared and dedicated protection against single link failure in WDM grooming networks and develop an ILP formulation for each of them. We extend our research on the full protection design to partial protection where the backup capacity is smaller than the primary capacity. We present ILP formulations and design a dynamic routing strategy named shortest-available-least-congested routing.
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