Client  Server Processes

A network  application  consist  of pairs  of process that send message to one  another  over a network. For  example  in a web application a client  browser process exchanges messages with a web server process. For  each pair of communicating processes were typically  label one of the two processes as the client and the another  process as the  server. With the web a browser is a client process and a web server sea server process. With P2P file sharing the peer that is downloading the file is labelled as the client and  the peer that is uploading the file  is labelled as the sever.

We defines  the client and server  processes as follow;

In the context  of a communication session between  a pair of processes the process that initiates  the communication is  labelled as the client. The process that  waits to be contacted to begin  the session  to the server.