Request–response or request–reply is one of the basic methods computers use to communicate to each other. When using request–response, 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. One can think of request–response as being like a telephone call, where you call someone and they answer the call. Compare this with one-way computer communication, which is like the push-to-talk or “barge in” feature found on some phones and two-way radios, where a message is sent without waiting for a response. Sending an email is an example of one-way communication.