A TLD or Top-Level Domain is identified as being among the highest level domains in the internet’s Domain Name System (DNS). It can easily be identified by the letters directly after the final dot in a website address.
Take the internet address www.domain.com as an example; .com is the top-level domain name which shows that it is commercial; domain is the second-level domain name; and www is a subdomain name. Combined together, they are considered a Fully-Qualified Domain name (FQDN). The addition of http:// to an FQDN makes it a complete URL.
A top-level domain name is established in the part of the name space called the DNS root zone. The root zone consists of the numeric IP addresses and names for all the TLDs in the root zone file. There are more than 1,500 TLDs including IDNs, ccTLDs, and gTLDs, contained in the DNS root zone and which are assigned to the Root Zone Database.
Relevance of TLDs
A TLD quickly gives a website viewer an idea about the purpose of the owner of the website or its location of origin. For example, a .gov TLD indicates that a website is affiliated with the government, and a .edu TLD indicates an educational institution.
Regulation of TLDs
The allocation of TLDs is regulated by an identified organisation that has been directed by ICANN (the Internet Corporation for Assigned Names and Numbers) to do so.
Categories of TLDs
ICANN recognises different categories of TLDs, which have been grouped based on their functions, reasons for creation and geographical area. They include:
- Generic Top-Level Domains (gTLDs): This group of TLDs are the most common and widely applied for during TLD registration. Examples are the .com TLD for commercial organisations and .edu for educational institutions. More in this category include .org, .net, .biz, and .info, among others. gTLDs can be registered for by almost anyone, but there exists a cluster that is strictly controlled based on geography, brand, industry, and even wealth.
- Country-Code Top-Level Domains (ccTLD): For these, they are owned by countries and always contain only two letters which are derived from the country code of the applying country. This ensures the uniqueness of the top-level domain and gives each country the reserved right to use a specific ccTLD.
- Sponsored Top-Level Domains (sTLD): In this category of TLDs, each TLD has a sponsor representing the larger community under their specialised sector. For example, the .jobs TLD is sponsored by the Society of Human Resources Management, which limits registration to members of the human resources recruitment and management industry. There are other sponsors for different TLDs, and application for these can only be processed by companies that are within a particular scope specified by the sponsoring business sector.
- Infrastructure Top-Level Domain: The only infrastructure top-level domain is the Address and Routing Parameter Area (ARPA). This TLD is exclusively reserved for internet-infrastructure purposes. It is managed for the IETF by the IANA (Internet Assigned Numbers Authority).
- Reserved Top-Level Domain: There are four major TLDs in this group of TLDs that are reserved and are not used in the production networks associated with the worldwide domain name system. They include:
- .example - which is available for use only with examples.
- .invalid - this is available only to invalid domain names.
- .localhost – this is a top-level domain available for local computers.
- .test – is used exclusively for test domain names.
Evolution of the TLD Application Process
Over the years, changes have been made in the process required to apply for a TLD. These changes account for the diverse changes implemented in new generation companies.
Who Can Apply for a Top-Level Domain?
Application for a top-level domain is open to anyone seeking to obtain a domain name. Before applying for a top-level domain, registrants need to go over the guidelines and note the important requirements as requested by the ICANN.
Expansion of TLD
In 2009, ICANN recommended that the TLD system be expanded to make it possible for anyone to register and secure an unused combination of letters as a TLD for their own exclusive use. According to the Chief Executive of ICANN, Paul Levins, an expansion like that would lead to the creation of thousands of new TLDs in the coming years. The success of this expansion can be analysed under certain factors:
- Availability of TLDs: Over the years, ICANN has approved the creation of over 900 generic top-level domains for public use, creating a more diverse TLD library for users to choose from. This creation caters for companies seeking to get a domain name for themselves but do not fit into the requirements of the other categories allowed by the regulatory body.
- Security of TLDs: The explosion in the number of top-level domains creates a conflict between domain names used within a corporate network and those that can be easily registered via a public network.
Paying for Top-Level Domains
The use of a TLD operates under a subscription policy and it plays an important role when registrants make their choices about which TLD to acquire.
Choosing a Top-Level Domain
Choosing a TLD is generally a simple task to perform, however, many people get confused or undecided when they have to come to a decision as to which TLD to use in their domain name. Normally, the first factor to consider is the purpose of the website. A .com or .biz TLD would work better if the company in question has a buyer/seller mode of raising capital. If it is solely for an organisation to promote itself online, then a .org TLD extension would work better.
If the website viewership is targeted at a specific geographical area, obtaining a ccTLD is the route that is most preferred. This captures the local area entirely whilst also creating an online presence for the business. Another important factor taken into consideration is search engine optimisation (SEO) and how a given TLD might affect a website’s rankings in search engine results pages.