rotocol) The global standard networking protocol. TCP/IP was developed in the 1970s for the U.S. military's ARPAnet, the world's first packet-switched network. It was created to enable all types of computers to transmit data to each other via a common format and language and even withstand disruption in the event of war. Vinton Cerf and Bob Kahn were major contributors (see IP on Everything
). See ARPAnet
and TCP/IP abc's
The ARPAnet evolved into the Internet, and the Internet's immense influence caused TCP/IP to become the global standard for both local and long-distance networks (LANs and WANs). Every form of data rides over TCP/IP with one exception: the legacy telephone networks (see SS7
). However, a huge amount of voice does use TCP/IP (see VoIP
Reliable and Unreliable Modes of Delivery
The TCP/IP suite includes 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, 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. 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 or dynamically assigned (see IP address
TCP/IP is a layered protocol with each layer passing data to the next (for details, see TCP/IP abc's
). The most common applications are shown here (Web/HTTP, email/SMTP, file transfer/FTP). Layer 3 delivers a "datagram" to Layers 2 and 1, which are responsible for the actual signal transmission.
Along with Web, email and file transfer, this diagram shows many of the network utilities that ride over TCP/IP. See URI