Understanding TCPIP and Related Concepts

Understanding TCP/IP and Related Concepts

TCP/IP is the network communications protocol of choice in Windows Server 2003. It permeates Windows from end to end as the preferred network protocol. But what is TCP/IP, and how does it work? Before you can get to the business of configuring this flexible protocol, you need to have a basic understanding of its key points.

TCP/IP is a suite of protocols that allows hosts, networks, and operating systems to communicate with each other. As you might know, TCP/IP was originally built for the U.S. Department of Defense (DoD) to allow its mainframes and servers to chat with each other locally and remotely.

TCP/IP actually evolved from a network created by a vast research agencythe Advanced Research Projects Agency (ARPA)which performed advanced technical research for the DoD. This collection of networks, called ARPAnet, connected research centers, such as universities, to each other and with DoD sites, such as the Pentagon. ARPAnet was designed to provide a redundantly reliable network that could survive the loss of one or more hosts. The thought wasand it was a very realistic thought at the timethat in the event of a nuclear war, it was very likely that several cities would be destroyed, taking with them their network hosts. ARPAnet was designed to allow continued communications between remaining locations.

ARPAnet ran on top of the original routing protocol, Network Core Protocol (NCP). NCP was composed of the TCP and IP protocolstwo separate protocols that are examined later in this chapter. The basic design of TCP/IP is simple, fault tolerant, routable, and vendor neutral.

Originally, TCP/IP was used to connect mainframes. However, the 1980s saw the evolution of Unix and personal computers (PCs). Although it faced some resistance, Unix eventually led the way, at the University of California, Berkeley, in integrating TCP/IP to connect these PCs. The Macintosh world used the AppleTalk protocol, and much of the Windows world stuck with either the NetBEUI protocol or the NWLink IPX/SPX-compatible protocol for connectivity with NetWare servers. One day, almost out of nowhere, this thing called the World Wide Web happened; because of the WWW, everyone needed TCP/IP, and they needed it right away.