Abstract
The IETF is currently working on service differentiation for the Internet. However, service differentiation at the IP layer is useless without support of lower layers. This support is even more critical in wireless environments because of the dynamism of the channel conditions and of the network topology. In this paper, we present a service differentiation support for the IEEE 802.11. The idea is to scale the contention window according to the priority of each flow or user. Preliminary simulation results are shown when using this mechanism with TCP and UDP.