Internet Application Protocols and Services

 

A Taxonomy of Internet Services

The application protocol layer utilises the transmission medium and the lower and middle protocol layers as an infrastructure, in order to deliver services. Some services are provided by computers for other computers, some by computers but for people, and some by people and for people. Key services that are available over the underlying infrastructure include e-mail and the World Wide Web (which together dominate Internet traffic volumes), file transfer and news (also referred to as 'netnews' and by its original name 'Usenet news'). There are, however, several score other services, some of which have great significance to particular kinds of users, or as enablers of better-known services.

During the early years, the services that were available were primarily remote login to distant machines (using rlogin and telnet from 1972), email (from 1972), and file transfer protocol (ftp, from 1973). In 1973, email represented 75% of all ARPANET traffic. By 1975, mailing lists were supported, and by 1979-82 emoticons such as (:-)} were becoming established. By 1980, MUDs and bulletin boards existed. The email service in use in 2004 was standardised as early as 1982. Synchronous multi-person conversations were supported from 1988 by Internet Relay Chat. This was also significant because the innovation was developed in Finland, whereas a very large proportion of the technology had been, and continues to be, developed within the U.S.A.

By 1990, over 100,000 hosts were connected, and innovation in application-layer protocols, and hence in services, accelerated. Between 1990 and 1994, a succession of content-provision, content-discovery and content-access services were released, as existing news and bulletin-board arrangements were reticulated over the Internet, and then enhanced protocols were developed, including archie (an indexing tool for ftp sites developed in Canada), the various 'gopher' systems (generic menu-driven systems for accessing files, supported by the veronica discovery tool), and Brewster Kahle's WAIS content search engines. Between 1991 and 1994, the World Wide Web emerged, from an Englishman and a Frenchman working in Switzerland; and in due course the Web swamped all of the other content-publishing services. By 1995, it was already carrying the largest traffic-volume of any application-layer protocol.

Exhibit 3.4, which is a revised version of an exhibit in Clarke (1994c), provides a classification scheme for the services available over the Internet.

http://www.anu.edu.au/people/Roger.Clarke/II/OzI04.html