A Min-Max Optimization Problem on Traffic Grooming in WDM Optical Networks

Abstract

In SONET/WDM networks, a wavelength channel is shared by multiplexed low-rate traffic demands. The multiplexing/de-multiplexing is known as traffic grooming and performed by SONET Add-Drop Multiplexers (SADM). The grooming factor, denoted by k, is the maximum number of low-rate traffic demands that can be multiplexed in one wavelength. Since SADMs are expensive, a key optimization problem in traffic grooming is to minimize the total number of required SADMs to satisfy the full connectivity for a given set of traffic demands. In this paper, we study traffic grooming from a different point of view. We consider a Min-Max optimization problem to minimize the number of SADMs at the network node where the number of required SADMs is the maximum over all nodes. We focus on the Unidirectional Path-Switched Ring networks with arbitrary duplex traffic demands. We prove the NP-hardness of this Min-Max optimization problem, and propose a linear time ( k+1 2 + 2)-approximation algorithm. We then show that the approximation algorithm achieves the worst case lower bound. We also study the all-to-all traffic pattern, and propose an algorithm achieving solutions only a constant factor away from the optimal ones. Extensive simulations are conducted as well to validate the performance of our algorithm.

Efficient Integration of Logical Topology Design and Survivable Traffic Grooming for Throughput Enhancement in WDM Optical Networks

“…The problem of traffic grooming is addressed in [15] by considering a Min-Max optimization problem where the objective is to minimize the number of ADMs at the network node where the number of required SADMs is maximum over all nodes. Two dynamic restoration schemes for STG in WDM mesh networks that improve blocking probability and restoration performance are proposed in [16].…”

“…Since it is extremely important to efficiently utilize the bandwidth offered by a lightpath, the problem of traffic grooming [3]- [5], [10]- [15], [17]- [19] and [21]- [28] has attracted a lot of research interest. Since a lightpath in a traffic-groomed optical network carries huge amount of data and 100 or more lightpaths may traverse a fiber, the disruption of this traffic due to a fiber cut (link failure), even for a short period of time is a serious event.…”

“…Since networks resources are scarce, it is necessary that any heuristic solution to the traffic grooming problem with or without survivability must minimize the use of these resources. Consequently the objective of [10] and [17] is to minimize the number of transceivers (alternatively the number of lightpaths), the objective of [19] and [22] is to minimize the number of transceivers and the number of wavelengths, the objective of [5], [11] and [14] is to minimize electronic switching cost and the objective of [15] is to minimize the use of Add Drop Multiplexers (ADMs). The work [4] addresses minimizing of lightpaths, minimizing of wavelengths used and minimizing the number of traffic hops (delay), each through a separate heuristic.…”