By Dr. Philip Baczewski, Associate Director of Academic Computing

What's in a Name?

a refresher course on Internet addressing

and some new developments in the organization of the internet

One of the first steps to understanding a concept is applying a name to it. A name helps classify an idea or object and creates a label under which similar ideas or objects can be placed. Names, once adopted in general use, aid communication by implying a longer description to a short label. Whether it's rap music, religious right, Internet technology, global warming, or stock market -- all of those labels instantly expand to multiple concepts and images.

Names are important to the Internet as well. It is names which allow us to identify places and people within that electronic environment. Whether it's greenpeace.org, unt.edu, amazon.com, internic.net, or whitehouse.gov -- all of those names represent large organizations with very differing purposes and identities. Internet names are so important that many companies now identify themselves as much by their internet name as their corporate logo. In fact, the book selling amazon.com, which sprang up completely as an Internet-based business, couches their entire identity in their Internet address. Obviously, on the Internet, there's a lot in a name.

What's in a Domain?

Names like unt.edu and whitehouse.com are only part of the Internet addresses that we are used to working with. Such a name actually identifies a computer network associated with an organization. For example, unt.edu is part of all the addresses used within the University of North Texas' Internet network. In Internet terminology, such a collection of addresses is called a domain.

Domains are organized in hierarchies. If you've used the Internet for a while you recognize some of the top-level hierarchy names such as .edu (educational institutions), .gov (government organizations), .net (Internet network service providers), .org (non-profit organizations), and .com (commercial entities). Another set of top-level domain hierarchy names consists of the two-digit country codes -- .us for the United States, .ca for Canada, .uk for Great Britain, etc.

Domain names can have as many hierarchical levels as necessary. For example, .acs.unt.edu is the Academic Computing Services domain at UNT, .cas.unt.edu is the College of Arts and Sciences domain, etc. Each subdomain can have further levels of hierarchy as necessary to specify the specific services offered by that organization via the Internet network. This is why some Internet addresses can be quite long with multiple parts separated by periods (.).

What's in a number?

Domain names are only half the story when you are talking about internet addresses. Names are convenient for people, but are not as useful to computer systems. Computer systems are just big calculators at heart and work much more efficiently with numbers than with names. So every Internet address name is associated with a numeric Internet address. Numeric addresses are four sets of three-digit numbers separated by periods. For example, 129.120.209.029 is the numeric equivalent of www.unt.edu.

Most people remember names much more easily than numbers, and names provide an associative reference that helps the memory process and places an object within a learned framework of concepts. That's why at the heart of any Internet network is a system to translate the names that are useful to people into the numbers that are useful to computers.

Domain Names Service (DNS) is critical to the function of what we know as the Internet. DNS consists of a database of names and numbers as well as software to communicate those names and numbers between different computers. Each domain, like unt.edu, has one central computer repository for its names and addresses, although this information can be duplicated on other computers to provide a backup service or increase network efficiency.

These repositories of Internet addresses are called DNS servers. Most Internet software, like Netscape Communicator or Internet Explorer, has built-in functionality to connect to a DNS server and translate a name to a number. The number is what your computer uses to make a connection to a remote Internet computer. A local DNS server does not have all the addresses for the entire Internet stored in it. A DNS server can communicate with other DNS servers on the Internet to translate an address within the other server's domain.

What's in a service?

Domain Name Service is obviously very critical to the operation of any Internet network. If DNS "breaks" then unless you know the numeric address for a site, you can't communicate with it. It's kind of like knowing someone's name, but not having a phonebook handy -- it makes it much harder to call them on the phone.

The Internet worldwide is dependent upon a central repository of domain names. In the United States, there have been two government-sponsored organizations which have taken care of the tasks of registering domain names (so that multiple organizations do not end up using the same name) and translating names to numeric addresses. You can find out more about domain name registration by visiting www.internic.net. You can find out more about how Internet address numbers are assigned by visiting www.arin.net.

Next time: In next month's "Network Connection," I'll discuss a new proposal to centralize the registration of Internet names and numbers under one private organization, and how this might be a dramatic turning point in the growth and development.

Is any one reading this??? Address any comments or questions to baczewski@unt.edu.