CONTENTS


DNS

As the World Wide Web (WWW) is build on top of the Internet, it seems appropriate to use the naming system which was already in place. This naming system was the Domain Naming Service (DNS). Under this system, a machine on the Internet would have an address which would reflect the locational/political position of that machine.

The machine name blood.cs.tcd.ie would indicate that the machine was located in the Computer Science (cs) department of Trinity College Dublin (tcd) which is located in Ireland (ie). Thus the name space has been broken up into a hierarchical structure of domains within domains.

The main advantage of this system is that the problem of locating the machine to which a m to which a message is directed has been trivialised. Just look at the address, ie , so now the search continues in the Irish domain only. This process continues and just as the postal service delivers a letter to you or I, the message moves from office to office, each step it gets closer to it's destination.

In addition to the machines address, you can specify a user: gbrdshaw@alf2.tcd.ie in which case it is up to the destination machine to forward the messagfe to the user.


URLs

The Universal Resource Locator (URL) is an extension of the naming convention used by DNS. It adds a prefix, which is used to specify which of the Web ch of the Web services you request of that machine. Such services are HTTP & FTP etc. Also other information can be appended to the address. One such use is to specify the particular Web page you request, e.g. http://maedhbh.maths.tcd.ie/~project/.

Advantages

The advantages of the DNS/URL system is that the databases for storing information about the machines is distributed in a fashion where the owner of the machines is responsible for that data. The root name server(s), which is potentially very busy, actually has quite a light workload, relative to the amount of traffic it handles. It's job is to talk international requests and route them to the relivant country, from there the job belongs to someone else. The root name server(s) are currently maintained by internic.

Another important advantagetant advantage of this system, is the fact that the address gives an indication of the location of the resource. For example given the addresses for two mirror sites: http://sunsite.unc.edu/ and http://sunsite.doc.ic.ac.uk/ it is easy for is easy for a regular user of the Internet to know that the first site is in the US, and the second in England. Knowing this can allow you to access the resources quicker, by getting them relativly locally.


Disadvantages

The two main disadvantages of this type of naming are that it gives no indication of the topics contained within the Web page. And that the address is just that, it must be exactly correct. There is no room for substitution of names. You could not use Trinity College Dublin instead of tcd. Thus for a user, whether experienced or novice, it is nearly impossnearly impossible to come up with an address on a particular topic. The closest thing you would get is the address of a big corporate body, which has commercially available products connected with that topic.

Closing Remarks

DNS was never intended as a topical index to the shared resources of the Internet. It was designed for the job ed for the job of providing an efficient, distributed database of those resources. It's short comings are addressed by Search Engines , which although providing a topical index are not suited to routine traffic, such as E-Mail.

So we feel that the DNS style naming will always exist on big netorks. And extra services will be provided to allow topical indexing.


References

More information on DNS can be found here.

More information on URLs can be fou URLs can be found here.