The Domain Naming Convention for Internet User Applications (RFC0819)
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2019-Feb-14
Internet Society Requests For Comment (RFCs)
Z. Su: AUTHOR [+1]
This RFC is an attempt to clarify the generalization of the Domain Naming Convention, the Internet Naming Convention, and to explore the implications of its adoption for Internet name service and user applications.
Network Working Group Zaw-Sing Su (SRI) Request for Comments: 819 Jon Postel (ISI) August 1982
The Domain Naming Convention for Internet User Applications
For many years, the naming convention "<user>@<host>" has served the ARPANET user community for its mail system, and the substring "<host>" has been used for other applications such as file transfer (FTP) and terminal access (Telnet). With the advent of network interconnection, this naming convention needs to be generalized to accommodate internetworking. A decision has recently been reached to replace the simple name field, "<host>", by a composite name field, "<domain>" . This note is an attempt to clarify this generalized naming convention, the Internet Naming Convention, and to explore the implications of its adoption for Internet name service and user applications.
The following example illustrates the changes in naming convention:
ARPANET Convention: Fred@ISIF Internet Convention: Fred@F.ISI.ARPA
The intent is that the Internet names be used to form a tree-structured administrative dependent, rather than a strictly topology dependent, hierarchy. The left-to-right string of name components proceeds from the most specific to the most general, that is, the root of the tree, the administrative universe, is on the right.
The name service for realizing the Internet naming convention is assumed to be application independent. It is not a part of any particular application, but rather an independent name service serves different user applications.
2. The Structural Model
The Internet naming convention is based on the domain concept. The name of a domain consists of a concatenation of one or more <simple names>. A domain can be considered as a region of jurisdiction for name assignment and of responsibility for name-to-address translation. The set of domains forms a hierarchy.
Using a graph theory representation, this hierarchy may be modeled as a directed graph. A directed graph consists of a set of nodes and a
Su & Postel [Page 1]
RFC 819 August 1982;
collection of arcs, where arcs are identified by ordered pairs of distinct nodes . Each node of the graph represents a domain. An ordered pair (B, A), an arc from B to A, indicates that B is a subdomain of domain A, and B is a simple name unique within A. We will refer to B as a child of A, and A a parent of B. The directed graph that best describes the naming hierarchy is called an "in-tree", which is a rooted tree with all arcs directed towards the root (Figure 1). The root of the tree represents the naming universe, ancestor of all domains. Endpoints (or leaves) of the tree are the lowest-level domains.
U / | \ / | \ U -- Naming Universe ^ ^ ^ I -- Intermediate Domain | | | E -- Endpoint Domain I E I / \ | ^ ^ ^ | | | E E I / | \ ^ ^ ^ | | | E E E
Figure 1 The In-Tree Model for Domain Hierarchy
The simple name of a child in this model is necessarily unique within its parent domain. Since the simple name of the child’s pa...