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The root of the Internet

Every computer user who has dealt with a file system is familiar with a hierarchical means of storage and division. The Internet follows this model, too. Sort of.

At the very top of the Internet system is the 'un-named root' (a logical starting point that provides access to the first level of domain names, a sort of Registry of Registries). Underneath this come the 'top-level' domain names (TLDs) - which originally consisted of seven generic suffixes (com, .net, .org, .edu .gov, .mil and .int) - and the geographically-specific two-letter country codes (ccTLDs).

The TLDs were intended to help designate the purpose of Web sites with .com representing commercial use of Web space, .org for organisations, .net for network providers, .edu for education, .gov for government sites, .mil for the military, and .int for international organisations.

Similarly, the ccTLDs help designate a site's country of origin: foodstore.nz would originate from New Zealand and alimentari.it from Italy.

The idea is that the naming scheme allows a choice between geographical or organisational naming systems. (You can check out the popularity of all the various country codes on the Net here).

New TLDs

In November 2000, ICANN (the Internet Corporation for Assigned Names and Numbers) decided to add seven new TLDs to help ease the 'crowding' around the .com namespace, i.e. people and organisations were using .com for want of a more suitable designation of the purpose of their Web site. The seven suffixes - .biz, .info, .name, .pro, .museum, .aero. and .coop - emerged from the forty-four serious applications (with .kids for children's content and .xxx for adult-oriented sites being among those rejected).

'This is a first giant step for domain-kind,' said Esther Dyson, chairman of ICANN, at the time. But subsequently there have been a number of delays and teething problems - mainly involving disputes over right of ownership - to the rollout of the new addresses. The .biz domain was particularly affected.

The second-level

Moving further down the pyramid, as it were, the structures found within the country codes vary. While, for example, you can have .co.uk or .gov.uk, you simply have .fr for France.

In theory, you could have a further geographic sub-division at the third level. Conceivably, if the national governing body so decided, the second-level domains could be further sub-divided - on a geographic basis, perhaps - underneath the second level. (Hypothetically, .co.uk could be preceded by county codes, to identify Northumbrian businesses from Cornish ones. Hypothetically, I repeat). In practice, this would only make administration of the domain more complex.

A good Web site for keeping track of the various country codes can be found here. Not only can you find out the letters associated with Israel or Australia, for example, you can find the details of the registrar with responsibility for that particular slice of Internet real estate.

As you are probably aware, you parse a domain name from left to right. Take the domain name pcpro.co.uk as an example. Taken hierarchically, in terms of how it would be considered by the naming system, 'pcpro.co.uk' is the lowest level domain, referring to the Web site for a particular magazine in the UK. The second level domain is '.co.uk', which is the domain for commercial operators within the UK, and the top level domain is the country code for Britain: .uk.

Registrars and their Registries

Essentially, with these TLDs, matters come under a national jurisdiction. For each ccTLD, a national Registrar will be responsible for maintaining a Register Database of domain names. In theory, these administrators may further delegate the management of portions of the 'naming tree'.

Recently, for the United States, .us was made available for the general public to register, having previously been restricted to government-approved bodies, and the company NeuStar has been awarded control of that domain. For the UK, (i.e. .uk) the Registrar is Nominet.

This is not to say that Nominet and other Registrars generally deal with the public to register domain names - ISPs and the like will operate this service, effectively licensing the service from the national Registrar.

.me

In January 2002, a new domain name .me emerged. Whereas before, the Registry for .uk domain names allowed for various commercial, academic and organisational addresses, you could now register .me.uk addresses for 'personal' use.

It was the first new SLD (second level domain) to be introduced since Nominet was awarded control of the .uk Registry in 1996. Guidance notes for the use of .me can be read here and they include the warning that registrants should be 'natural persons' and any made on behalf of commercial organisations could be challenged.

The full details of the United Kingdom SLDs are as follows. Those managed by Nominet comprise: .me.uk (for personal use), .co.uk, .plc.uk and .ltd.uk (for commercial use), .org.uk (for non-commercial organisations), .net.uk (for ISPs) and .sch.uk (for schools).

As is the way with such things, certain domains require fulfilment of certain criteria. For example, .ltd.uk and .plc.uk require that the name of the company involved has indeed been registered with Companies House.

Other UK SLDs that are not managed by Nominet comprise: .ac.uk, .gov.uk, .nhs.uk, .police.uk and .mod.uk (Ministry of Defence). The government has

The strange case of Tuvalu

A classic story from the world of ccTLDs involves the little Pacific island of Tuvalu.

Finding itself the owner of the .tv suffix, the country found itself sitting on what seemed - back in the days before the dot-com collapse - a huge virtual resource. It was thought that with a useful URL you were halfway to being a dot-com millionaire. What was perceived as a cash cow, however, turned into something of a chimera (although Business.com once sold for a record $7.5m). In the case of Tuvalu, just think of the addresses in possible demand - whatson.tv, theguide.tv, inside.tv -

Possessing the very marketable ccTLD, the country cashed in. Having traditionally licensed rights to other countries for fishing in its international waters, Tuvalu now moved to cash in on countries licensing its Internet address. Reportedly, Tuvalu sold the right to license .tv domains to the TV Corporation for $50m (approximately £35m) together with further annual payments.

A further twist to the story, however, is provided by the threat of global warming. It seems the low-lying islands in the Pacific that constitute Tuvalu are actually becoming submerged under the rising sea levels. The Guardian, in a recent feature on the country, reported that islanders are already being evacuated to New Zealand in anticipation of the place becoming inhabitable.

The country most famous for its Internet presence may, sadly, soon have no other existence. A virtual country alone. Strange to think that the Internet will become a historic record of countries that once existed (other Pacific islands are similarly threatened)...

DNS

If you consider the domain name system rather convoluted and user-unfriendly, you should realise that this naming system overlays the use of (much more unfriendly) 32-bit integer numerical addresses, so called IP (Internet Protocol) addresses. The IP address for www.google.com, for example, is 216.239.51.101 and this can be entered into your browser with equal success.

Type in the wrong domain name or type in the wrong IP address, the result is the same - the HTTP 404 Error ('site not found'). Just imagine how frequent they would be if you had to remember the IP address of each site you wanted to visit!

As well as providing a more user-friendly interface, the use of logical host names allows independence from knowing the physical location of machines. This means a host may be moved to another network, with another physical address, without the end-user being aware.

It is the Domain Name System (DNS) that enables computers to 'resolve' human readable addresses to the correct IP address. And this DNS involves a distributed database to link hostnames to IP addresses.

Every Internet-using individual or organisation (or their Internet service provider) maintains a names server to help process routing requests from around the Net. The full pathway of requests and communications - what happens when you enter www.pcpro.co.uk into your browser's address bar - is actually quite involved, incorporating communications between browsers, root-level servers and intermediate primary and secondary domain name servers.

Essentially, your browser will contact a root-level domain name server, maintained by InterNIC, to request the address of the primary name server where the domain name records for your destination site - pcpro.co.uk, for example - can be found. In this case, .co.uk leads to Nominet, the Registrar responsible for maintaining .uk records. Next, having visited this primary name server to retrieve the relevant domain name information, your browser now knows the exact IP address where to find your requested site. Which it then does, retrieving the content of the site over HTTP and displaying it in the browser window.

The use of caching at all stages of the chain of communication helps to keep the system working efficiently and avoid repeated requests for the location details of popular sites. For example, if you have just accessed the PC Pro site and then a work colleague does the same, it is likely that the DNS information will be cached locally ready for the second request...

We could go into a lot more detail about DNS, but a separate Low-down article will be arriving shortly on this subject.

ICANN

Operators of the official registries - such as the company Afilias for the new .info top-level domain - are all appointed by ICANN (Internet Corporation for Assigned Names and Numbers). This is a non-profit corporation that coordinates the technical management of the Internet's domain name system.

Effectively, ICANN has taken over the administrative role for the Internet that was handled by the US government and military. The Americans intended to step back from this direct, hands-on role and the new body is also the official interface to all the commercial interests that now surround the Internet.

This role has attracted criticisms. 'Old timers' who remember the early days of the Internet and the Web bemoan some of the decisions taken by the new body. Certainly, where huge financial contracts are involved - for example, the right to govern the lucrative .com domain (awarded again to VeriSign) - suspicions can arise of unfair play. Accusations of behind-doors deals in smoke-filled rooms will naturally tend to gather around 'closed', specially-appointed organisations. At the very least, hackles will be raised in one part or another of the Internet-using community.

References

To read further about the use of domains and addresses on the Internet, here are a few links.

ICANN the non-profit corporation that coordinates the technical management of the Internet.

InterNIC the Web site of which has been set up to provide the public information regarding Internet domain name registration services

ccTLD information

World Wide Web consortium - the body responsible for Internet standards and protocols