An adaptive virtual path allocation policy for broadband networks

We propose a new policy for virtual path bandwidth allocation in broadband networks. Based on a threshold scheme, our policy handles the inherent tradeoff between bandwidth utilization and processing costs. In each virtual path controller the thresholds are chosen so as to keep bandwidth utilization high, while obtaining a low rate of processing requests. Two novel ideas are used in our threshold scheme: adaptivity, which results in a better prediction of future bandwidth requirements; and hysteresis, which prevents excessive processing of requests due to oscillations around thresholds. We tested the performance of our new bandwidth control scheme, and compared it with previously suggested schemes. The performance measures were the expected amount of unused bandwidth, the average signaling load and the blocking probability. Performance has been evaluated through numerical computations as well as by simulations. Our analysis is based on a time segmentation technique which allows us to reduce a Markov chain with NM states into M Markov chains with N states and a one-dimensional chain with M states. Our results show that our policy significantly improves upon previously suggested approaches.