Client-server model

Client-Server结构是一种网络架构，它把客户端与服务器区分开来。客户端发送请求到服务器，服务器接收并处理请求，然后返回结果给客户端。

---

The client-server model is a distributed applicaton structure that partitions tasks or workloads between the providers of a resource or service, call servers, and service requesters, called clients.

Often clients and servers communicate over a computer network on separate hardware, but both client and server may reside in the same system.

A server host runs one or more server programs which share their resources with the clients. A client does not share any of their resources, but requests a server’s content or service function.

Clients therefore initiate commmunication sessions with servers which await incoming requests. Examples of computer applications that use the client-server model are Email, network printing, and the World Wide Web.

---

Client and server role

The client-server characteristic describes the relationship of cooperating programs in an application. The server component provides a function or service to one or many clients, which initiate requests for such services.

Servers are classified by the services they provide. For example, a web server serves web pages and a file server serves computer files. A shared resource may be any of the server computer’s software and electronic components, from programs and data to processors and storage devices. The sharing of resources of a server constitutes a service.

Whether a computer is a client, a server, or both, is determined by the nature of the application that requires the service functions. For example, a single computer can run web server and file server software at the same time to serve different data to clients making different kinds of requests. Client software can also communicate with server software within the same computer. Communication between servers, such as to synchronize data, is sometimes called inter-server or serve