HTTP is the underlying system used to transport documents, images, and other media types found on the World Wide Web. The protocol consists of a small command language in which clients send commands and servers send results. Communication between client and server is based on generally short lived TCP/IP connections. Once the transaction is complete, the established connection is closed. Like HTML, HTTP has also gone through major revisions. The following sections will provide an overview of the features found in each of these revisions.