1.6 Applicability Statement

A client uses the PCCR Discovery Protocol to locate peers with the content it requires, in the context of the Peer Content Caching and Retrieval Framework. The protocol is thus appropriate only in settings where multiple peers and at least one content server support this framework. The framework, including this Discovery Protocol, offers the possibility of significant performance benefits in cases where the content server is available only over a relatively high-latency or low-bandwidth connection as opposed to the peers that are available over relatively higher-bandwidth, lower-latency ones.

The PCCR Discovery Protocol is used to find peers with the hashes listed in the Probe messages. It is not for discovering hashes for given names or URLs. It is necessary for the clients to contact the original content servers (as opposed to the peer caches) to obtain the Content Information data structure [MS-PCCRC] containing hashes corresponding to the contents.