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The TCP/IP Guide  9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)       9  TCP/IP Key Applications and Application Protocols            9  TCP/IP File and Message Transfer Applications and Protocols (FTP, TFTP, Electronic Mail, USENET, HTTP/WWW, Gopher)                 9  TCP/IP World Wide Web (WWW, "The Web") and the Hypertext Transfer Protocol (HTTP)

World Wide Web Addressing: HTTP Uniform Resource Locators (URLs) 1 HTTP Overview, History, Versions and Standards

The success of the World Wide Web is a result of the efficiency and usefulness of the complete hypermedia system it implements. We examined in the last section the basic concepts behind hypertext, and looked at two of the three major components that comprise the World Wide Web system: HTML and URLs. The third major component of the Web is arguably the most important: the protocol that actually transfers hypertext documents and other files between Web servers and Web clients (browsers). This is one of the most widely-known software protocols in all of networking: the Hypertext Transfer Protocol (HTTP).

In this section I provide a detailed description of the Hypertext Transfer Protocol. I begin with an overview of HTTP and a discussion of its history and versions, and the standards that define them. I then describe the operation of the protocol in five subsections. The first discusses HTTP's operation in general terms, focusing on how connections are established and maintained. The second describes HTTP messages and how they are formatted, and describes HTTP methods (commands) and status codes. The third details the many HTTP headers, which are critically important as they are the primary way that information is communicated between HTTP servers and clients. The fourth subsection provides information about how resources, called entities, are encoded and transferred in HTTP. The final subsection describes special features and capabilities of the modern HTTP protocol.

World Wide Web Addressing: HTTP Uniform Resource Locators (URLs) 1 HTTP Overview, History, Versions and Standards