Abstract
The increasing use of wireless networks has necessitated the development of a wireless networking infrastructure that supports quality of service (QoS) for multimedia communications. Proxy servers are gaining prominence in facilitating QoS assurance and intelligent resource allocation for multimedia services. In this paper, we propose a proxy-based framework that provides QoS support to mobile users. We describe the overall QoS architecture and implement a number of key QoS functions, including bandwidth allocation and synchronization. In this architecture, admission control is exercised to ensure the long-term availability of resources to mobile clients, where the resources include bandwidth for supporting required presentation rates and buffer for synchronizing media streams. Bandwidth allocation is implemented in Linux Traffic Control using Stochastic Fairness Queueing and Token Bucket Filter disciplines to provide bandwidth guarantees for the multimedia connections. An adaptive synchronization technique is also implemented in the proxy to synchronize multiple streams originating from different sources before transmitting them to the clients for presentation. Finally, a number of quality adaptation strategies that accommodate the diverse requirements and capabilities of clients are described.