TCP/IP is the default network protocol for Unix systems and is becoming popular as a protocol for Windows NT networks, even those unconnected to the Internet or Unix servers.
Most of the TCP/IP protocols were created by the Internet Activities Board (IAB), which consists of two task forces: the IETF (Internet Engineering Task Force) and the IRTF (Internet Research Task Force.) Most Internet protocols begin their lives as RFCs, or Request for Comments. These documents are created to propose new protocols or standards.
RFCs that have become standards are still referred to with an RFC number. RFC numbers are mentioned here for many of the protocols described in this chapter. The full text of RFCs is available from this URL:
The TCP/IP protocol suite includes a wide variety of protocols and services that are in common use on the Internet as well as on Windows NT and Windows 2000 networks. These include its namesake protocols, TCP (Transmission Control Protocol) and IP (Internet Protocol).
The various protocols that comprise the TCP/IP suite are organized according to the DoD (US Department of Defense) reference model, also known as the TCP/IP reference model. This model organizes protocols and services into four layers: Network Access, Internet, Host-to-Host, and Process/Application. The sections below describe each layer and give descriptions of the major protocols that act at each layer.