Collaborative proxy system for distributed Web content transcoding

Content transformation (or transc oding) proxies ha ve been recen tly proposed to tailor Web con tentto 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 net w ork.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 ectiv ely 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 cac he the transcoded version performs better than the coverage based caching policy that caches the more detailed version and the anticip atorycaching policy that caches both of these v ersions.