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Traffic grooming in next-generation optical WDM mesh networks

Wang Yao, University of Nebraska - Lincoln


The backbone of the current Internet is built on the long-haul and metro telecommunication networks, which are essentially first-generation optical networks. The first-generation optical networks use wavelength links as a physical layer transmission technology to connect adjacent network nodes and rely on the wavelength-division multiplexing (WDM) technology to meet the huge Internet traffic demands. The Internet traffic is still increasing at a fast pace due to the emerging broadband services. The next-generation optical networks are expected to have an optical transport layer which supports intelligent, automatic and reliable provisioning of optical channels for upper electronic layers such as IP/MPLS, ATM and SONET/SDH. Traffic grooming is an essential functionality in optical WDM networks where there is a huge gap between the bandwidth capacity of a wavelength and the bandwidth requirements of traffic connections. The goal of this dissertation work is to design cost-effective yet reliable next-generation optical WDM grooming networks by bridging the gap between the high-rate lightpaths at the transport-oriented optical layer and the low-rate multi-granularity sub-wavelength connections at the service-rich electronic layer. As telecommunication networks are evolving from interconnected ring topologies toward general mesh topologies, we study the traffic grooming in next-generation WDM mesh networks. In particular, four topics are addressed: constrained dynamic traffic grooming algorithms, survivable traffic grooming, performance analysis of traffic grooming, and sparse traffic grooming. We proposed dynamic traffic grooming algorithms based on three different approaches. The first approach is an adaptive routing approach based on auxiliary graph model. The second approach is a fixed-alternate routing approach. The third approach is a two-phase rerouting approach. Survivable traffic grooming (STG) addresses the provisioning and survivability of multi-rate connections jointly in optical WDM networks. It seeks to provide fault recovery capability for connections and minimize the consumption of spare capacities. We formulate the static STG problem subject to the shared risk link group (SRLG) constraints as an integer linear programming (ILP) problem. To address the high complexity of the ILP formulation, we also proposed three efficient heuristics to solve the static STG problem. Analysis is a convenient approach to evaluate system performance. We presented an analytical model to compute the blocking probability of traffic grooming. A sparse grooming network is a practical and economical solution for telecommunication carriers to generate revenues with stringent budgets. We proposed two grooming algorithms to efficiently utilize the grooming capabilities sparsely located in the network. We also addressed the grooming node placement (GNP) problem by proposing an efficient heuristic to intelligently place a limited number of grooming fabrics in the network. ^

Subject Area

Computer Science

Recommended Citation

Yao, Wang, "Traffic grooming in next-generation optical WDM mesh networks" (2005). ETD collection for University of Nebraska - Lincoln. AAI3186890.