What is P4P?
P4P (proactive provider participation for P2P) is a protocol designed to improve the use of available bandwidth in a P2P network by reducing the overall volume of traffic. The term P2P (peer-to-peer) refers to any transient network on the Internet that allows a geographically dispersed group of end users to directly access files from each other's computers. P4P differs from the traditional P2P protocol by intelligently selecting peers to optimize routing efficiency.
Originally, P2P technology was used for simple file sharing such as text and images. However, in recent years, more bandwidth-hungry applications have evolved such as streaming media, Internet television, full-motion videoconference activity and online gaming. The extensive use of these applications has given rise among some experts to a concern that the Internet might "break under the strain." A major part of the problem is a tendency for traffic among routers to be unevenly distributed, resulting in inefficient routing with unnecessary hops between end users.
P4P minimizes the number of routers and hops involved in media distribution by means of devices called peer trackers and Internet trackers. When a peer has data to send, it queries the peer tracker for available peers in the local network. The peer tracker returns the information, if any is available, to the sending peer. If no local peers are available, the peer tracker queries the Internet tracker for available peers on the larger Internet. The Internet tracker returns a list of active peers to the peer tracker, which in turn provides the information to the original initiating peer. In effect, P4P does "proactive research" to determine the most efficient possible way for data to be routed between end users before any data is actually exchanged.
P4P technology, originally introduced by Verizon, has been shown to increase performance by as much as several hundred percent over traditional P2P. The extent of the improvement in any particular situation depends on the nature of the data to be shared, the overall volume of traffic, the number of routers involved, the available bandwidth and the network topology.