Supporting Bandwidth Guarantee and Mobility for Real-Time Applications   on Wireless LANs
  The proliferation of IEEE 802.11-based wireless LANs opens up avenues for creation of several tetherless and mobility oriented services. Most of these services, like voice over WLAN, media streaming etc., generate delay and bandwidth sensitive traffic. These traffic flows require undisrupted network connectivity with some QoS guarantees. Unfortunately, there is no adequate support built into these wireless LANs towards QoS provisioning. Further, the network layer handoff latency incurred by mobile nodes in these wireless LANs is too high for real-time applications to function properly. In this paper, we describe a QoS mechanism, called Rether, to effectively support bandwidth guarantee on wireless LANs. Rether is designed to support the current wireless LAN technologies like 802.11b and 802.11a with a specific capability of being tailored for QoS oriented technology like 802.11e. We also describe a low-latency handoff mechanism which expedites network level handoff to provide real-time applications with an added advantage of seamless mobility. 
Srikant Sharma and Kartik Gopalan and Ningning Zhu and Gang Peng and   Pradipta De and Tzi-cker Chiueh