Peer Exchange

Peer exchange or PeX is a communications protocol that augments the BitTorrent file sharing protocol. It allows a group of users (or peers) that are collaborating to share a given file to do so more swiftly and efficiently.

In the original design of the BitTorrent file sharing protocol, peers (users) in a file sharing group (known as a "swarm") relied upon a central computer server called a tracker to find each other and to maintain the swarm. PEX greatly reduces the reliance of peers on a tracker by allowing each peer to directly update others in the swarm as to which peers are currently in the swarm. By reducing dependency on a centralized tracker, PEX increases the speed, efficiency, and robustness of the BitTorrent protocol.