InterNIC's purpose is to provide the various registry services needed for the Internet to operate effectively. Network Solutions handles the registration of domain names.
Domain names are the monikers that identify different computers and resources on the Internet.
So InterNIC assigns each computer or resource a domain name that corresponds to its IP address. You can't assign your own domain names arbitrarily. Each domain name must be unique, and you must register it with InterNIC's registration service. Domain names are composed of a hierarchy of names that appear in descending levels from right to left. The domain name you register with InterNIC will include only the first and second levels.