What is a Peer-to-Peer (P2P) network and how does it differ from client-server?

In P2P, peers share resources directly with no dedicated server — each peer acts as both client and server, with roles decided per request, unlike the fixed roles in client-server.

Peer-to-Peer (P2P) Network:

A network where two or more computers are connected and can share resources without a dedicated server.

Key characteristics:

• Every connected device (peer) can function as both a server and a client
• Roles are set on a per-request basis
• One computer might serve files while simultaneously being a client for another service

P2P Applications require:

• A user interface
• A background service running on each device

Example - Hybrid P2P: Some P2P applications use an index server where peers look up the location of resources stored on other peers, then connect directly to download.

Common P2P Applications:

• BitTorrent
• Direct Connect
• eDonkey
• Freenet
• Gnutella (LimeWire)

Key insight: Many P2P applications allow users to share pieces of files with multiple peers simultaneously - this is BitTorrent technology.

Go deeper:

• Peer-to-peer (Wikipedia) — how peers share resources directly without a dedicated server.