A domain name registry is a database of all domain names registered in a Top-Level. A registry operator, also called Network Information Center, part of the Domain Name System of the Internet, which maintains the database of domain names and generate zone files that convert domain names into IP addresses. Each NIC is an organization that manages the registration of domain names in top level domains, which it is responsible, controls the allocation policy name domain, and technically operates its top-level domain. It is potentially different from a domain registration. Domain names are managed by a hierarchy headed by the Internet Assigned Numbers Authority, which manages the top of the DNS tree by managing data in the root name servers.