Cache Hierarchies

When an organization has more than one proxy server, the proxies can share cached information among them. For example, if a web page exists in server A's cache, but not in the cache of server B, a user connected via server B might get the cached object from server A via server B. Inter-Cache Proto-col (ICP) and Cache Array Routing Protocol (CARP) can share cache information. CARP is considered the better protocol. Squid supports both protocols, and MS ISA Server supports CARP. For more information, see SourceForge. This sharing of cached information reduces bandwidth usage in organizations where more than one proxy is used.