Your ‘domain’ is uniquely identified by its name (domain name) and an Internet protocol (IP) number.
In the internet, the Domain Naming System (DNS) dictates that the domain name is composed of the ‘hostname‘ and its ‘network‘ such as earth.com. Earth is the hostname located in the comnetwork. Earth can also be used as a network. So then, the domainAmerica.earth.com uses America as the hostname in the earthnetwork, which is in the comnetwork. America is also referred to as the subdomain of the earth.comdomain.
The Internet Protocol (IP) number is the address identifying which computer in the internet is hosting a domain. The vast numbers of computers in the world currently used requires an address of 128 bits.
The Uniform Resource Locator (URL) is the address used in a browser to locate web sites and files on the internet. It is composed of three parts. For example, http://America.earth.com/central is composed of: 1) the network protocolhttp; 2) the domain name America.earth.com; and the file location central. The domain name America.earth.com, consists of the hostnameAmerica, the second level networkearth, and the primary networkcom. For an URL like http://earth.com, the hostname is earth in the network of com.