QoS management in a World Wide Web environment which supports continuous media

Until recently the World Wide Web (WWW) and associated browser technologies have provided no support for the delivery of continuous media in real time. Instead, files have been down-loaded completely and then played back. There are now some systems available that provide support for streaming of audio and/or video between WWW servers and clients. However the Internet comprises a vast range of networks and end systems with different characteristics, which together determine the level of continuous media service quality that can be supported for a given connection. A quality of service (QoS) model is required that will encompass the heterogeneity of the Internet environment. In this paper we present our approach to delivering continuous media in WWW environments, based on a model of end-to-end QoS management. We have developed an experimental implementation that permits real-time delivery of audio and video within the WWW. Significantly our implementation incorporates end-to-end QoS negotiation and QoS adaptation, which adjusts the delivery stream to match prevailing network and system conditions. We describe the design and implementation of our WWW-based QoS model. We then discuss some issues arising from our experience, including a proposal for future work based on a more open, object oriented architecture.