Peer-to-Peer Architecture

Peer-to-peer architecture removes the central server from a distributed system. It exists because the client-server model has a center that someone must pay for and protect. There is a load balancer, an application tier, a database. Clients ask and servers answer, and capacity is something the operator buys: when traffic grows, you add servers and pay for them.

Peer-to-peer inverts this.

There is no privileged server. Every participant, called a peer, is simultaneously a consumer and a provider of resources