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TCP/IP Concepts   «Prev  Next»
Lesson 1

Introduction to TCP/IP Networking Concepts

Question: What are the key TCP/IP networking concepts?
This module will cover the fundamental concepts of TCP/IP networking and how it relates to distributed computing.
By the end of this module, you will be able to:
  1. Describe in general terms the different layers in the TCP/IP protocol
  2. Understand the rules governing IP address classes and netmasks
We engage in many protocols every day: asking and responding to questions, negotiating business transactions, working collaboratively, and so on. Computers also engage in a variety of protocols. A collection of related protocols is called a protocol suite. The design that specifies how various protocols of a protocol suite relate to each other and divide up tasks to be accomplished is called the architecture or reference model for the protocol suite. TCP/IP is a protocol suite that implements the Internet architecture and draws its origins from the ARPANET Reference Model (ARM) [RFC0871].
The TCP/IP architecture evolved from work that addressed a need to provide interconnection of multiple different packet-switched computer networks. This was accomplished using a set of gateways (later called routers) that provided a translation function between each otherwise incompatible network. The resulting 'concatenated' network or catenet (later called internetwork) would be much more useful, as many more nodes offering a wide variety of services could communicate. The types of uses that a global network might offer were envisioned years before the protocol architecture was fully developed


The global network concept underpinning the ARPANET and later the Internet was designed to support many of the types of uses we enjoy today. However, getting to this point was neither simple nor obvious. The success resulted from paying careful attention to design and engineering, innovative users and developers, and the availability of sufficient resources to move from concept to prototype and, eventually, to commercial networking products. This chapter provides an overview of the Internet architecture and TCP/IP protocol suite, to provide some historical context and to establish an adequate background for the remaining chapters. Architectures (both protocol and physical) really amount to a set of design decisions about what features should be supported and where such features should be logically implemented. Designing an architecture is more art than science, yet we shall discuss some characteristics of architectures that have been deemed desirable over time. The subject of network architecture has been undertaken more broadly in the text by Day [D08], one of few such treatments.
The TCP/IP Model or Internet Reference Model, is a layered abstract description for communications and computer network protocol design.
It was created in the 1970s by DARPA for use in developing the Internet's protocols.
The structure of the Internet is still closely reflected by the TCP/IP model.
The TCP/IP reference model is the network model used in the current Internet architecture. It has its origins back in the 1960's with the grandfather of the Internet, the ARPANET. This was a research network sponsored by the Department of Defense in the United States. The following were seen as major design goals:
  1. ability to connect multiple networks together seamlessly
  2. ability for connections to remain intact as long as the source and destination machines were functioning
  3. to be built on flexible architecture
The reference model was named after two of its main protocols, TCP (Transmission Control Protocol) and IP (Internet Protocol). They choose to build a packet-switched network based on a connectionless internetwork layer.