A generic Top Level Domain, designated as gTLD is the most widely used category of TLDs (top level domains). It is the TLD of an internet address that indicates the address is generically associated with a particular domain class such as .org, .net, or the more popular .com. An internet address or domain name contains a number of parts including a top-level, also called a domain extension.
Unlike other categories of top-level domains managed by IANA (the Internet Assigned Numbers Authority), an organ of ICANN (the Internet Corporation for Assigned Names and Numbers), gTLDS are generally unrestricted, and appear with three or more characters. gTLDs may be operated and managed either by an ICANN approved registry operator or the sponsoring organisation.
Categories of gTLDs
The root zone of the internet contains 21 gTLDs which are categorised into the following:
Generic: gTLDs under this category are meant for general use. They include .org, .com., .net, and .info.
Generic restricted: This category of gTLDs are meant to be used strictly for their designated purposes and for them to be registered, proof of eligibility must be provided in accordance with the guidelines set for each of them. They include .pro, .name, and .biz.
Sponsored: Sponsored gTLDs are meant to be used only by organisations or entities within specific industries or sectors. They include .travel, .mobi, .jobs, .gov, .edu, .coop, .cat, .asia, and .aero.
Infrastructure: There is only one TLD in this category and it is managed by IANA. It is. arpa and it is used strictly for technical infrastructure purposes.
In spite of the classifications, all domains other than those with a country or geographic designation are commonly regarded as generic TLDs. As of June 2017, the number of gTLDs introduced into the internet stand at 1226, with 76 still in process.
Background of gTLDs
1984 saw the publishing of RFC 920 by Joyce Reynolds and Jon Postel. RFC 920 not only suggested that TLDs be introduced in the internet’s root zone, but also outlined how they should be categorised and how each of the proposed TLDs be used. These TLDs were:
- .org for organisation
- .mil for military
- .com for commercial
- .edu for education
- .gov for government
- two-character codes (alpha-2) for countries registered in the ISO-3166-1, and
- the temporary .arpa, which was designated for the switch to the internet from ARPANET (the internet’s predecessor).
.arpa is the exception and so is regarded as a domain extension. Initially, it was used to transmit the ARPANET’s hostname conventions in the DNS. Now, it is used strictly for technical infrastructure purposes, and is not open for anyone to register domains using it.
The other TLDs, alongside .net, were executed in the root zone in January 1985. While .net, .com, .org, and .edu were open for anyone to register, .mil and .gov were reserved for use by the military and the government of the United States. Three years later in 1988, the IANA introduced .int for treaty-established international organisations.
The first designated registrar charged with registering and hosting domain names was the Network Information Centre (NIC), which administered and managed the all the original TLDs. At the time, the centre was managed by SRI International.
Postel introduced RFC 1591 in 1994, where the structure of the DNS and TLDs was explained. It categorised the original TLDs as gTLDs and separated them from the two-character ISO-3166 country codes. The RFC also posited that it was unlikely for new TLDs to ever be introduced, an assertion that has since been disproved.
Rapid expansion of the domain name industry
In July 1997, the Clinton administration in a bid to encourage international participation and competition in the domain name industry, mandated the Department of Commerce to move the technical management of the DNS to a private entity.
Following a consensus by the internet community that a new private entity manage the DNS and that new gTLDs be created, ICANN was established in October 1998. The introduction of new gTLDs has been a huge part of the ICANN’s agenda since the body was established.
Development of new gTLDs
Towards the end of the year 2000, ICANN announced that it was releasing seven new TLDs, which were .pro, .name, .museum, .info, .coop, .biz, and .aero. They were not activated immediately, but periodically between June 2001 and June 2004 when .pro became fully operational even though it had become a gTLD since May 2002.
A number of other gTLDs have been approved since then, including .xxx which was approved in March 2011, after ICANN was found to have violated its own bylaws by refusing to approve the application in 2007. ICANN is not slowing down as far as introducing new gTLDs is concerned, and it is anticipated that their new rules concerning TLD naming will lead to the registration of new gTLDs.