Many of the same people who developed the Unix operating system also worked on the network that would eventually become the Internet. They designed TCP/IP as the standard group of network protocols for this purpose. Because Linux is a clone of Unix, it is also customized for TCP/IP. However, TCP/IP is only one of several protocol stacks associated with modern networking.
TCP/IP is named for two of its component protocols, the Transport Communications Protocol and the Internet Protocol. TCP/IP actually includes several hundred individual protocols. Officially, it is known as the TCP/IP Protocol Suite.
Before we dig into the details of TCP/IP, we ll step back and take a look at the fundamentals of computer networks, both small and large. We need a way to identify every computer on a network, and a standard method of transferring data. Several other protocol stacks are available, and in this chapter we ll address two of them: NetBEUI and IPX/SPX.
NetBEUI is the NetBIOS Enhanced User Interface, developed by Microsoft and IBM. IPX/SPX is also named for two of its component protocols, Internetwork Packet Exchange and Sequenced Packet Exchange. Like TCP/IP, IPX/SPX includes a substantial number of individual protocols.
To help software designers develop different protocols, they needed specifications for standard levels of communication. Their agreements are documented through the International Organization for Standardization (ISO) as the OSI model of networking, where OSI stands for Open Standards Interconnection
While the OSI model is often applied to TCP/IP, many designers subscribe to a conceptually similar four-level protocol stack. Many TCP/IP services would otherwise require software at several different OSI levels.
If you re not interested in all this theory, you can jump ahead to what you can do with TCP/IP, starting with IP addressing. Two versions of IP addresses are available. IP version 4 addressing is still in common use in the United States, but the newer IP version 6 addresses are coming into frequent use in other parts of the world. This chapter covers the following topics: