Also found in: Dictionary, Thesaurus, Medical, Legal, Financial, Acronyms, Wikipedia.
Related to TCP/IP: TCP/IP stack


McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


Transmission Control Protocol over Internet Protocol.

The de facto standard Ethernet protocols incorporated into 4.2BSD Unix. TCP/IP was developed by DARPA for internetworking and encompasses both network layer and transport layer protocols. While TCP and IP specify two protocols at specific protocol layers, TCP/IP is often used to refer to the entire DoD protocol suite based upon these, including telnet, FTP, UDP and RDP.

See also ICMP, SMTP, SNMP.
This article is provided by FOLDOC - Free Online Dictionary of Computing (


(Transmission Control Protocol/Internet Protocol) The global standard networking protocol. Developed in the 1970s under contract from the U.S. Department of Defense, TCP/IP was invented by Vinton Cerf and Bob Kahn.

TCP/IP prepares and forwards data packets over private local area and wide area networks (LANs and WANs) as well as the Internet. In fact, the Internet is the world's largest TCP/IP network.

Every form of data rides over TCP/IP with one major exception: the legacy non-Internet telephone networks (see SS7). A huge amount of voice does however use TCP/IP (see VoIP).

Reliable and Unreliable Modes of Delivery
The TCP/IP suite provides two transport methods. TCP is used for packets that must arrive in perfect form such as financial data, and UDP is deployed for real-time applications such as voice and video calling, where there is no time to retransmit erroneous packets.

TCP/IP Is a Routable Protocol
TCP/IP is commonly referred to as just "IP," because the IP part of the protocol routes packets from one network to another within an organization or over the Internet (see illustration below).

An IP packet contains source and destination addresses of both the host computers and the networks they reside in. The terms "TCP/IP network" and "IP network" are synonymous.

The IP Address Identifies Everything
Every node in a TCP/IP network requires an IP address (an "IP") which is either permanently assigned or dynamically assigned (see IP address and DHCP). For an explanation of the TCP/IP layers, see TCP/IP abc's and OSI model. For a conceptual picture, see communications protocol. See protocol stack, TCP/IP port, DNS and IP on Everything.

The TCP/IP Stack
The TCP or UDP transport layer 4 sends packets to IP network layer 3, which adds its own header and delivers a "datagram" to a data link layer 2 protocol such as Ethernet, ATM or SONET. See datagram.
Copyright © 1981-2019 by The Computer Language Company Inc. All Rights reserved. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction is strictly prohibited without permission from the publisher.