The TCP/IP Guide  9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)       9  Name Systems and TCP/IP Name Registration and Name Resolution            9  TCP/IP Name Systems: Host Tables and Domain Name System (DNS)                 9  TCP/IP Domain Name System (DNS)

DNS Components and General Functions 1 DNS Domains and the DNS Hierarchical Name Architecture

The name space is the most fundamental part of any name system, since it is what defines the ways that the names themselves are created. The name space tells us what form names may take, and provides the rules for how they are created. Most importantly, it specifies the architecture of the names—the internal structure of names themselves. This in turn has a critical influence on how name registration and resolution work, making an examination of name space and architecture issues the obvious place to start in learning the details of DNS.

In this section I describe the concepts behind the DNS name space and its structure. I begin with an overview of the DNS name space and description of the hierarchical architecture it uses. I then provide more detail on the name structure, and also explain the terminology often used to refer to parts of the name space. I provide a formal description of DNS labels and the official and unofficial rules for creating domain names. I conclude with a description of domain name specifications, and explain the concept of “qualification” and how fully-qualified and partially-qualified names differ.

DNS Components and General Functions 1 DNS Domains and the DNS Hierarchical Name Architecture