DNS is modeled after a tree architecture. The root of the tree is unnamed. Below the root comes a group of nodes. Each of these nodes represents a domain within the network. Associated with each node is a unique label, a domain name of up to 63 characters. The domain names are managed by the NIC (Network Information Center), which delegates control of the top-level domains to countries, universities, governments, and organizations.

An example of a domain name is "com", the commercial domain. WRS (Wind River Systems) is a commercial organization, thus it fits under the commercial domain. The NIC has given WRS the authority to manage the name space under "wrs.com". WRS uses this space to name all the hosts in its network.