Online Distributed Traffic Grooming on Path Networks

The grooming factor C of a WDM optical network is the number of connections that can share the bandwidth of each wavelength and the process of grouping the requests that will share each wavelength is called traffic grooming. The goal of traffic grooming is either to reduce the transmission cost by reducing the number of wavelengths or to reduce the hardware cost by reducing the number of Add-Drop Multiplexors (ADM). In this paper, we investigate traffic grooming for directed path networks with online connection requests and distributed routing algorithms. When connection requests are online, the virtual topology that results from the assignment of ADMs to wavelengths cannot be changed with each request. The design of efficient virtual topologies that minimize either the number of ADMs needed to satisfy any set of connection requests or the blocking of connection requests depends strongly on the routing algorithm. We show how to design the best possible virtual topologies, independently of the routing algorithm, when each node is equipped with the same number of ADMs, and we analyze the performance of distributed greedy routing algorithms