Transmission Control Protocol/Internet Protocol

   Abbreviated TCP/IP. A set of communications protocols first developed by the Defense Advanced Research ProjectsAgency (DARPA) in the late 1970s.

   The set of TCP/IP protocols encompasses media access, packet transport, session communications, file transfer, e-mail, and terminal emulation.

   TCP/IP is a widely published open standard, and while completely independent of any specific hardware or software company, it is supported by a huge number of vendors and is available on many different computers, from PCs to mainframes, running many different operating systems. Many corporations, universities, and government agencies use TCP/IP, and it is also the basis of the Internet.

   TCP/IP is separated from the network hardware and will run over Ethernet, token-ring, X.25 networks, and dial-up connections. It is a routable protocol, so datagrams can be sent over specific routes, and it has reliable and efficient data-delivery mechanisms. TCP/IP uses a common expandable addressing scheme, so any system can address any other system, even in a network as large as the Internet, and new networks can be added without service disruptions.

   The popularity that the TCP/IP family of protocols enjoys today did not arise just because the protocols were available or even because the U.S. government mandated their use. They are popular because they are robust, solid protocols that solve many of the most difficult networking problems and do so in an elegant and efficient way.

   See also Address Resolution Protocol; File Transfer Protocol; Hypertext Transfer Protocol; Internet Control Message Protocol; Internet Mail Access Protocol; Internet Protocol; Post Office Protocol; Simple Mail Transfer Protocol; Simple Network Management Protocol; Telnet; tn3270; User Datagram Protocol.