Internet Protocol Suite

The Internet Protocol Suite, commonly known as TCP/IP, is the set of communications protocols used in the Internet and similar computer networks. It is named after two of its most prominent protocols, the Transmission Control Protocol (TCP) and the Internet Protocol (IP). The development of TCP/IP was initiated by the United States Department of Defense to ensure and sustain robust, fault-tolerant communication with packet switching.

Overview

The Internet Protocol Suite provides end-to-end data communication specifying how data should be packetized, addressed, transmitted, routed, and received. This functionality is organized into four abstraction layers which are used to sort all related protocols according to the scope of networking involved. From lowest to highest, the layers are:

• The Link layer
• The Internet layer
• The Transport layer
• The Application layer

Each layer solves a set of problems involving the transmission of data, and provides a well-defined service to the upper layer protocols based on the use of services from some lower layers.

Link Layer

The link layer is the lowest layer in the TCP/IP model. It includes the protocols used to describe the local network topology and the interfaces needed to effect transmission of Internet layer datagrams to next-neighbor hosts. Protocols like Ethernet, Wi-Fi, and Asynchronous Transfer Mode (ATM) are included in this layer.

Internet Layer

The internet layer has the task of exchanging datagrams across network boundaries. It provides an uniform networking interface that hides the actual topology (layout) of the underlying network connections. It is therefore also referred to as the layer that establishes internetworking; indeed, it defines and establishes the Internet. This layer defines the addressing and routing structures used for the TCP/IP protocol suite. The core protocols of this layer are IP, ICMP, ARP, and RARP.

Transport Layer

The transport layer provides communication from one application to another. Protocols like TCP and UDP are used here. TCP supports connections-oriented services and guarantees the delivery of data packets in the same order in which they were sent. UDP provides connectionless service and offers no guarantee for delivery order or even delivery itself.

Application Layer

The application layer contains all protocols and methods that fall into the realm of process-to-process communications via an Internet Protocol network. Applications like WWW, email, FTP, and VoIP operate at this layer.

Impact and Importance

The Internet Protocol Suite is the basis for the operation of the Internet and has been instrumental in its growth and adoption. It supports a complex architecture that has scaled from modest beginnings to the global network of networks seen today.

See Also

• List of network protocols (OSI model)
• Internet
• Computer network