An example of TCP/IP in action is a person accessing a website.
Origin of TCP/IPT(ransmission) C(ontrol) P(rotocol)/I(nternet) P(rotocol)
- Transmission Control Protocol/Internet Protocol. This is the standard now widely in use for computers to communicate on networks, especially the internet.
tcp/ip - Computer Definition
Referring to the ARPA protocol suite that provides the basis for what has evolved into the Internet and, therefore, often is referred to as the Internet protocol suite. This is a four-layer protocol suite that maps into the OSI Reference Model that followed a few years later.Table T-2 includes the major protocols that comprise the TCP/IP protocol suite as they relate to the ARPA and OSI models. Table T-2: TCP/IP Protocol Suite
|OSI Layer||ARPA Layer||Protocol|
|7 Application||Process/ Application||FTP File Transfer Protocol||SMTP Simple Mail Transfer Protocol||SNMP Simple Network Management Protocol||TELNET Telecommunications Network|
|4 Transport||Host-to-Host||TCP Transmission Control Protocol||UDP User Datagram Protocol|
|3 Network||Internet||ARP Address Resolution Protocol||ICMP Internet Control Message Protocol||IP Internet Protocol|
|2 Data Link||Network Interface||LAN, MAN, WAN Network Interface Card (NIC)|
|1 Physical||Transmission Media|
(Transmission Control Protocol/Internet Protocol) The most widely used communications protocol. TCP/IP prepares and forwards data packets over a network such as Ethernet. Developed in the 1970s under contract from the U.S. Department of Defense, TCP/IP was invented by Vinton Cerf and Bob Kahn. This de facto Unix standard is the protocol of the Internet and the global standard for local and wide area networks, the major exception being the traditional networks of the telephone companies. However, telephone companies that deploy voice over IP (VoIP) networks are, in fact, using TCP/IP as well (see VoIP). TCP/IP is commonly referred to as just "IP," which is the network layer of the protocol (see illustration below); thus, the terms "TCP/IP network" and "IP network" are synonymous. Reliable and Unreliable Modes of Delivery The TCP/IP suite provides two transport methods. TCP ensures that data arrive intact and complete, while UDP just transmits packets. TCP is used for data that must arrive in perfect form, and UDP is used for real-time applications such as voice over IP (VoIP) and video calling, where there is no time to retransmit erroneous or dropped packets. IP Makes It Routable TCP/IP is a routable protocol, and the IP network layer in TCP/IP provides this capability. The header prefixed to an IP packet contains not only source and destination addresses of the host computers, but source and destination addresses of the networks they reside in. Data transmitted using TCP/IP can be sent to multiple networks within an organization or around the globe via the Internet, the world's largest TCP/IP network. 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 how the various layers in TCP/IP work, 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.