Introduction (Hypertext, URL, Domain Name)

Introduction (Hypertext, URL, Domain Name)

HyperText Transfer Protocol (HTTP)

HTTP (Hypertext Transfer Protocol) is perhaps the most popular application protocol used in the Internet (or The WEB).

• HTTP is an asymmetric request-response client-server protocol as illustrated.  An HTTP client sends a request message to an HTTP server.  The server, in turn, returns a response message.  In other words, HTTP is a pull protocol, the client pulls information from the server (instead of serverpushes information down to the client).

• HTTP is a stateless protocol. In other words, the current request does not know what has been done in the previous requests.
• HTTP permits negotiating of data type and representation, so as to allow systems to be built independently of the data being transferred.
• Quoting from the RFC2616: “The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia information systems. It is a generic, stateless, protocol which can be used for many tasks beyond its use for hypertext, such as name servers and distributed object management systems, through extension of its request methods, error codes and headers.”