Collaborative proxy system for distributed Web content transcoding

Abstract

Content transformation (or transcoding) proxies have been recently proposed to tailor Web content to device characteristics of Web clients. In this paper, we address the problem of distributing the computational load caused by object transcoding throughout a collaborative proxy system organized in a hierarchical network. We evaluate through simulation the impact of load distribution and caching policies on users' response time. We nd that the simple global policy that captures the proxy load information along the request path can provide reasonably good load sharing, and that, to e ectively share the load, it is necessary to provide the edge proxies a mechanism to push up some transcoding load. On the caching policy, we examine policies that allow di erent versions of an object to be cached. Our study shows that the demand based caching policy which has the transcoding proxy cache the transcoded version performs better than the coverage based caching policy that caches the more detailed version and the anticipatory caching policy that caches both of these versions. 1.