Paper #1

Performance Study of Congestion Price
based Adaptive Service

Xin Wang and Henning Schulzrinne
Columbia University


In a network with enhancements for QoS support, pricing of network services based on the level of service, usage, and congestion provides a natural and equitable incentive for applications to adapt their sending rates according to network conditions. In this paper, we first propose a dynamic, congestion-sensitive pricing algorithm, and also develop the demand behavior of adaptive users based on a physically reasonable user utility function. We then develop a simulation framework to compare the performance of a network supporting congestion-sensitive pricing and adaptive reservation to that of a network with a static pricing policy. We also study the stability of the dynamic pricing and reservation mechanisms, and the impact of various network control parameters. The results show that the congestion-sensitive pricing system takes advantage of application adaptivity to achieve significant gains in network availability, revenue, and user-perceived benefit relative to the fixed-price policy. Congestion-based pricing is stable and effective in limiting utilization to a targeted level. Users with different demand elasticity are seen to share bandwidth fairly, with each user having a bandwidth share proportional to its relative willingness to pay for bandwidth. The results also show that even a small proportion of adaptive users may result in a significant performance benefit and better service for the entire user population - both adaptive and non-adaptive users. The performance improvement given by the congestion-based adaptive policy further improves as the network scales and more connections share the resources.
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- Last revised: Weds Jun 27 20:56:29 EDT 2000