Traffic Grooming in Translucent Optical Ring Networks.
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Date
2003-12-07
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Abstract
The exponential growth of the Internet has resulted in an ever increasing demand for bandwidth. Carrier networks which form the backbone of the Internet, have been designed to carry only voice signals with predictable traffic patterns and anticipating slow growth of the network. With the advances in fiber optics and wavelength division multiplexing (WDM) optical networking is the key to satisfy the data-driven bandwidth demand. These technologies enable simultaneous transmission of signals on separate high-speed channels at different wavelengths. While the bandwidth provided by these channels is very high, individual traffic demands are at the sub-wavelength level. This mismatch can be overcome by multiplexing several lower rate connections onto the high-speed channels in a cost-effective manner. This technique is referred to as traffic grooming. Traffic grooming in WDM networks has been a widely addressed problem in recent years. Traffic grooming and its constituent subproblems have been proven to be NP-complete for even the most elemental of network topologies. The ring topology has been the target of a large number of the studies because of its practical relevance. However, most existing studies concentrate on some objective function that is aggregated over all the network nodes, such as the total number of ADMs used or the total amount of opto-electro-optical (OEO) routing performed. From a practical point of view, it is likely that every network node would be provisioned similarly. Hence a min-max objective, seeking to minimize the OEO equipment needed at the node which needs the maximum of such equipment is more appropriate. Such objectives are usually harder to optimize than aggregate objectives which are themselves known to be computationally intractable. In this thesis, we study traffic grooming in a unidirectional ring network under different traffic patterns for the min-max objective. We define two heuristic approaches based on decomposition; one is based on grouping the nodes, and the other on partitioning the traffic matrix. We show that the second approach is more general, but is costlier in terms of computation; further, we indicate traffic families for which the first approach may be expected to perform nearly as well as the more complex one. We also investigate several variations of these two main approaches. We present numerical results validating the performance of the algorithms.
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min-max objective, translucent optical ring networks, traffic grooming
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Degree
MS
Discipline
Computer Science
