A client-server connection is a connection between two or more systems in which one is acting as a server and the others are acting as a client. This is typically done to allow information to be accessible to multiple users on a large network. Such connections can be used on a small scale, such as for local business networks, or for large-scale networks such as those used in online gaming or social networking sites. A client-server connection can be direct, between two machines, or may be indirect and involve several layers of interconnected systems.
The client-server connection is one of the most important aspects of any client-server system design, and this can be a physical connection or a long-distance connection through multiple relays. In general, however, this connection basically consists of any way in which two or more separate systems, the client and the server, are able to communicate to transmit data. The client-server connection can be quite simple, such as a machine acting as server connected to another machine through a physical connection, such as an Ethernet cable, or more complicated, such as a server connected to thousands of users through the Internet.
A simple client-server connection can be a physical connection between a single server and one or a few clients. The server acts as the system on which data can be stored, to which one or more client machines can be connected. Client machines are able to be used individually and without the information necessary on the server, though they are able to gain access to the data kept on the server. When a server request is sent by a client, the server responds by sending the requested data through that connection to the client.
Complicated networks can be created in which this client-server connection is repeated hundreds or thousands of times. A major social networking website or online gaming service may provide thousands or hundreds of thousands of clients with connections to a server. Multiple servers can then be used to increase the number of users that can be connected as clients, so that millions of clients can be connected to these various servers for information access. Multitiered systems are often created to reduce the strain on servers, providing systems between the client and server that can handle certain requests or act to “direct traffic” for the server. A client-server connection is in contrast to peer-to-peer connections in which individual clients connect to each other, instead of a server, to share data.