Web Caching and Replication

10.3. Issues in Cooperative Cache Consistency

Cooperative proxy caching introduces some interesting consistency issues that are specific to this environment. Before discussing them further, we should stress that any such issues are important only insofar as there is a possibility of a stale delivery by individual proxies. Indeed, if each individual proxy always served fresh content, so would cooperating proxies. As we have seen earlier, cache consistency mechanisms of individual proxies achieve very low stale delivery rate. Thus, one may argue that the issues in this section are not very important. However, there is a difference between a rare occurrence of an undesirable event and a guarantee that the event would not occur. Our discussion includes ...