The World Wide Web: Http
The World Wide Web: HTTP
1. Introduction
One of the major communication technologies that has changed the way people live and work is the Web. Perhaps what appeals the most users about the Web is that it is on demand. Users receive what they want, when they want it. This is unlike broadcast radio and television, which force users to "tune in" when the content provider makes the content available. In addition to being on demand, the Web has many other wonderful features that people love and cherish. It is enormously easy for any individual to make any available over the Web; everyone can become a publisher at extremely low cost. Hyperlinks and search engines help us navigate through an ocean of Web sites. Graphics and animated graphics stimulate our senses. Forms, Java applets, Active X components, as well as many other devices enable us to interact with pages and sites.
And more and more, the Web provides a menu interface to vast quantities of audio and video material stored in the Internet, audio and video that can be accessed on demand.
2. Overview of HTTP
The Hypertext Transfer Protocol (HTTP), the Web's application-layer protocol, is at the heart of the Web. HTTP is implemented in two programs: a client program and a server program.
The client program and server program, executing on different end systems, talk to each other by exchanging HTTP messages. HTTP defines the structure of these messages and how the client and server exchange the messages. It is useful to review some Web terminology.
A Web page (also called a document) consists of objects. An object is a simple file -- such as an HTML file, a JPEG image, a GIF image, a Java applet, an audio clip, etc. -- that is addressable by a single URL. Most Web pages consist of a base HTML file and several referenced objects. For example, if a Web page contains HTML text and five JPEG images, then the Web page has six objects: the base HTML file plus the five images. The base HTML file references the
1. Introduction
One of the major communication technologies that has changed the way people live and work is the Web. Perhaps what appeals the most users about the Web is that it is on demand. Users receive what they want, when they want it. This is unlike broadcast radio and television, which force users to "tune in" when the content provider makes the content available. In addition to being on demand, the Web has many other wonderful features that people love and cherish. It is enormously easy for any individual to make any available over the Web; everyone can become a publisher at extremely low cost. Hyperlinks and search engines help us navigate through an ocean of Web sites. Graphics and animated graphics stimulate our senses. Forms, Java applets, Active X components, as well as many other devices enable us to interact with pages and sites.
And more and more, the Web provides a menu interface to vast quantities of audio and video material stored in the Internet, audio and video that can be accessed on demand.
2. Overview of HTTP
The Hypertext Transfer Protocol (HTTP), the Web's application-layer protocol, is at the heart of the Web. HTTP is implemented in two programs: a client program and a server program.
The client program and server program, executing on different end systems, talk to each other by exchanging HTTP messages. HTTP defines the structure of these messages and how the client and server exchange the messages. It is useful to review some Web terminology.
A Web page (also called a document) consists of objects. An object is a simple file -- such as an HTML file, a JPEG image, a GIF image, a Java applet, an audio clip, etc. -- that is addressable by a single URL. Most Web pages consist of a base HTML file and several referenced objects. For example, if a Web page contains HTML text and five JPEG images, then the Web page has six objects: the base HTML file plus the five images. The base HTML file references the