Design and implementation of a user-centered content distribution network

Replicating Web documents at a worldwide scale can help reduce user-perceived latency and wide-area network traffic. We present the design and implementation of Globule, a platform that allows Web server administrators to organize a decentralized replication service by trading Web hosting resources with each other. Globule automates all aspects of such replication: document replication, selection of the most appropriate replication strategies on a per-document basis, consistency management and transparent redirection of clients to replicas. To facilitate the transition from a nonreplicated server to a replicated one, we designed Globule as a module for the Apache Web server. Therefore, converting Web documents should require no more than compiling a new module into Apache and editing a configuration file.