Request–response, or
request–reply, is one of the basic methods computers use to communicate with each other, in which the first computer sends a request for some data and the second computer responds to the request. Usually, there is a series of such interchanges until the complete message is sent; browsing a
web page is an example of request–response communication. Request–response can be seen as a telephone call, in which someone is called and they answer the call.