A peer-to-peer (P2P) computer network utilizes varied connectivity linking participants in a set of connections and the collective bandwidth of network members rather than the usual centralized resources where a fairly low number of servers provide the core value to a service or application. Peer-to-peer networks are usually used for connecting nodes via largely improvised connections.
Such networks are useful for many purposes: Sharing content files containing audio, video, data or anything in digital format is very common, and realtime data, such as telephony traffic, is also passed using P2P technology. File sharing typically follows the P2P model, where the files are stored on and served by personal computers of the users. Generally, people who engage in file sharing on the Internet both give (upload) files and receive files (download).
There are plenty of excellent free/open-source P2P file sharing software available today. Here’s my list: