Chapter 1. Overview of TCP/IP

All of us—engineers, educators, scientists, and business people—who use Windows NT or any other advanced desktop operating system have second careers managing that system. Networking increases the complexity of this new task.

Administration tasks such as adding users and local tape backups are isolated to one independent computer system. Not so with network administration. Once you place your computer on a network, it interacts with many other systems. The way you do network administration tasks has effects, good and bad, not only on your system, but also on other systems on the network. A sound understanding of basic network administration benefits everyone.

Networking computers dramatically enhances their ability to communicate—and most computers are used more for communication than computation. Many mainframes and supercomputers are busy crunching the numbers for business and science, but the number of such systems pales in comparison to the millions of systems busily moving mail to a remote colleague or retrieving information from a remote repository. Further, when you think of the hundreds of millions of desktop systems that are used primarily for preparing documents to communicate ideas from one person to another, it is easy to see why most computers can be viewed as communications devices.

The positive impact of computer communications increases with the number and type of computers that participate in the network. One of the great benefits of TCP/IP is that it provides interoperable communications between all types of hardware and all kinds of operating systems.

With the advent of Windows NT, Microsoft acknowledged the importance of interoperable networking. NT was designed from the ground up to include a variety of networking software. The most important of these is TCP/IP, which provides NT systems with truly interoperable data communications.

This book is a practical, step-by-step guide to configuring and managing TCP/IP networking software on Windows NT computer systems. TCP/IP is the software package that dominates data communications. It is the leading communications software for enterprise intranets, and it is the foundation of the worldwide Internet.

The name TCP/IP refers to an entire suite of data communications protocols. The suite gets its name from two of the protocols that belong to it: the Transmission Control Protocol and the Internet Protocol. Although there are many other protocols in the suite, TCP and IP are certainly two of the most important.

The first part of this book discusses the basics of TCP/IP and how it moves data across a network. Let’s start with a little history.

TCP/IP and the Internet

In 1969 the Advanced Research Projects Agency (ARPA) funded a research and development project to create an experimental packet-switching network. This network, called the ARPANET, became the foundation for the Internet. Today it is larger than ever and encompasses more than 95,000 networks worldwide. The Internet has grown exponentially since 1983—roughly doubling in size every year. Through all of this incredible change one thing has remained constant: the Internet is built on the TCP/IP protocol suite.

Because TCP/IP is required for Internet connection, the growth of the Internet has spurred interest in TCP/IP. As more organizations become familiar with TCP/IP, they see that its power can be applied in other network applications. The Internet protocols are often used for local area networking, even when the local network is not connected to the Internet. TCP/IP is also widely used to build enterprise networks. TCP/IP-based enterprise networks that use Internet techniques and World Wide Web tools to disseminate internal corporate information are called intranets. TCP/IP is the foundation of all of these varied networks.

Microsoft recognized the importance of TCP/IP for server systems and included TCP/IP support in Windows NT from the beginning. The role of Windows NT as a TCP/IP server, both inside the enterprise and in the global Internet, grows every year.

TCP/IP Features

The popularity of the TCP/IP protocols did not grow rapidly just because the protocols were there, or because connecting to the Internet mandated their use. They met an important need (worldwide data communication) at the right time, and they had several important features that allowed them to meet this need. These features are:

  • Open protocol standards, freely available and developed independently from any specific computer hardware or operating system. Because it is so widely supported, TCP/IP is ideal for uniting different hardware and software, even if you don’t communicate over the Internet.

  • Independence from specific physical network hardware. This allows TCP/IP to integrate many different kinds of networks. TCP/IP can be run over an Ethernet, a token ring, a dial-up line, an FDDI net, and virtually any other kind of physical transmission medium.

  • A common addressing scheme that allows any TCP/IP device to uniquely address any other device in the entire network, even if the network is as large as the worldwide Internet.

  • Standardized high-level protocols for consistent, widely available user services.

Protocol Standards

Protocols are formal rules of behavior. In international relations, protocols minimize the problems caused by cultural differences when various nations work together. By agreeing to a common set of rules that are widely known and independent of any one nation’s customs, diplomatic protocols minimize misunderstandings; everyone knows how to act and how to interpret the actions of others. Similarly, when computers communicate, it is necessary to define a set of rules to govern their communications.

In data communications these sets of rules are also called protocols. In homogeneous networks, a single computer vendor specifies a set of communications rules designed to use the strengths of the vendor’s operating system and hardware architecture. But homogeneous networks are like the culture of a single country—only the natives are truly at home in it. TCP/IP attempts to create a heterogeneous network with open protocols that are independent of operating system and architectural differences. TCP/IP protocols are available to everyone, and are developed and changed by consensus—not by the fiat of one manufacturer. Everyone is free to develop products to meet these open protocol specifications.

The open nature of TCP/IP protocols requires publicly available standards documents. All protocols in the TCP/IP protocol suite are defined in one of three Internet standards publications. A number of the protocols have been adopted as Military Standards (MIL STD). Others were published as Internet Engineering Notes (IEN)—though the IEN form of publication has now been abandoned. But most information about TCP/IP protocols is published as Requests for Comments (RFC). RFCs contain the latest versions of the specifications of all standard TCP/IP protocols.[1]

As the title Request for Comments implies, the style and content of these documents is much less rigid than most standards documents. RFCs contain a wide range of interesting and useful information, and are not limited to the formal specification of data communications protocols. As a network system administrator, you probably will read some of the RFCs yourself.

[1] Interested in finding out how Internet standards are created? Read The Internet Standards Process, RFC 1310.

Get Windows NT TCP/IP Network Administration now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.