Essential TCP/IP

One of the most important technical issues that you must understand before you can achieve anything on the Internet is TCP/IP (transmission control protocol/Internet protocol). TCP/IP actually refers to a group of protocols that are used for data transmission and it is the communications protocol used in most Unix networks, the Internet and as a safe neutral protocol in many mixed platform networks.

TCP/IP was developed in 1973 but was not published as a standard until 1983 when it was chosen as the standard protocol for communications over the new ARPAnet wide area network (an early forerunner of the Internet). One of the reasons for TCP/IP's popularity in academic networks and within Unix stems from its origins in the University of California, Berkeley which developed the BSD series of Unix products each incorporating the new TCP/IP protocol.

TCP/IP is used because it has a number of very important benefits. It:

• will run on a wide range of hardware, including Ethernet, Token Ring and X.25

• will work on different computer platforms and operating systems, including Macintosh, Unix, PC, mainframe and PDA!

• is an open standard that is not owned by any manufacturer

• has a standard method of addressing that can uniquely identify each host on a vast network such as the Internet

• can route data via a particular route to reduce traffic or to bypass a faulty link

The TCP/IP protocol has five layers and can be closely modeled to the ISO/OSI seven layer network model.

Figure 3.1: TCP/IP...