A client is a computer that connects to a server or a remote computer, in order to use its resources. For example, many corporate networks comprise a client computer for each employee, each of which connects to the corporate server. The server provides resources like files, information, iInternet and intranet access, and external processing power.
In the same way that a client computer connects to a remote server, a client can also be a piece of software that performs the same function.
The relationship between the client and the server can be organised in different ways, however, there are two options that are most widely used. These are the "Client-server" model and the "Peer-to-peer" (P2P) model.
The client-server model is the relationship between two computers in which one, the client, makes a service request from another, the server. The key point about a client-server model is that the client is dependent on the server to provide and manage the information.
For example, websites are stored on web servers. A web browser is the client which makes the request to the server, and the server sends the website to the browser.
In a P2P network, no single provider is responsible for being the server. Each computer stores files and acts as a server. Each computer has equal responsibility for providing data.