Dynamic application-level bandwidth negotiations for WWW

In order to provide appropriate quality of service for WWW multimedia access, and to perform adaptive content transformation to tradeoff Web presentation quality for faster WWW access, reliable bandwidth negotiation mechanisms are required to estimate the instantaneous network conditions. However, heterogeneity among WWW entities, dynamics of daily network usage, and bandwidth requirements for different WWW documents make it difficult to discover the instantaneous network conditions and to deliver the different levels of service that is most appropriate for the diverse range of clients. The authors propose an application-level bandwidth negotiation mechanism for WWW, to ensure the delivery of Web presentations that is most appropriate to suit the dynamic network constraints of the users. Firstly, techniques involved in estimating the round trip time, available bandwidth, and bandwidth bottleneck for each Web object are discussed. Then these techniques are run on different HTTP and network environments to find out their applicability. It is found that in a typical WAN/Internet environment, the accuracy of bandwidth negotiation achieved is very high and a small site table (with about 50 entries) can provide an access hit ratio of over 90%.