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The TCP/IP Guide  9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)       9  Name Systems and TCP/IP Name Registration and Name Resolution            9  Name System Issues, Concepts and Techniques

Name System Issues, Concepts and Techniques 1 2 3 Name System Functions: Name Space, Name Registration and Name Resolution

A Paradox: Name Systems Are Both Essential and Unnecessary?

What's interesting about name systems is that they are extremely important to networks… but at the same time, they often aren't strictly necessary for a network to operate. This seeming paradox is due again to the difference between humans and computers. Computers only need the numeric addressing scheme, not the “human names” assigned to them. So the computers and the network can still work—but it will be much harder for us people to use them!

An example of this can most readily be seen when a problem disables the operation of a part of the Domain Name System (DNS) used to provide naming services on the Internet. Technically, DNS isn't needed to use the Internet, because all communications use IP addresses. This means that even though you might normally access CNN's web site at “www.cnn.com”, you could instead just use the IP address 64.236.16.20 if DNS wasn't working.

The problem is that prior to reading this, you probably had no idea what the IP address of CNN's Web site was, and that's true of almost everyone else who uses their site as well. Also, you might want to check not just CNN's Web site, but perhaps one, two or twenty other news sites. It would be difficult to remember the numbers for even a small percentage of the thousands of different Web sites on the Internet, so each time you wanted to access a resource you’d have to manually look up its address, as shown in Figure 229.

Figure 229: Internetwork Access Without A Name System

When there is no name system, a user must know the address of any device he or she wishes to access on the internetwork. Since most of us have limited memories for numbers, this means each access must be preceded by an inefficient, tedious manual address look-up.

Name System Issues, Concepts and Techniques 1 2 3 Name System Functions: Name Space, Name Registration and Name Resolution

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