Description: ICP is a lightweight message format used for communicating among WWW caches. ICP is primarily used in a cache mesh to locate specific WWW objects in neighbor caches. A cache in such a mesh may have numerous choices for resolving a URL request. ICP is used to assist in selecting the most appropriate location. One cache will send an ICP query to its neighbors. The neighbors will send back ICP replies indicating a ``HIT'' or a ``MISS.'' All current ICP implementations use UDP as the transport. Messages consist of a 20-byte fixed header and a variable-sized payload. The payload is normally a URL string. ICP has been in use since 1995. We estimate there are approximately 3000 Web caches in operation that support ICP. The purpose of this BOF is to propose formation of the ICP Working Group. The goal of the ICP working group is only this: To document existing, deployed ICP version 2 implementations as an Informational RFC. There will be two documents: one describing the protocol and message format, and another describing how ICP is currently applied to Web cache meshes. This will be the second ICP BOF. For more information, please visit the ICP Development page at http://www.nlanr.net/Cache/ICP/.