IAB Technical Comment on the Unique DNS Root
RFC 2826

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 00

Network Working Group                        Internet Architecture Board
Request for Comments: 2826                                      May 2000
Category: Informational

              IAB Technical Comment on the Unique DNS Root

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2000).  All Rights Reserved.

Summary

   To remain a global network, the Internet requires the existence of a
   globally unique public name space.  The DNS name space is a
   hierarchical name space derived from a single, globally unique root.
   This is a technical constraint inherent in the design of the DNS.
   Therefore it is not technically feasible for there to be more than
   one root in the public DNS.  That one root must be supported by a set
   of coordinated root servers administered by a unique naming
   authority.

   Put simply, deploying multiple public DNS roots would raise a very
   strong possibility that users of different ISPs who click on the same
   link on a web page could end up at different destinations, against
   the will of the web page designers.

   This does not preclude private networks from operating their own
   private name spaces, but if they wish to make use of names uniquely
   defined for the global Internet, they have to fetch that information
   from the global DNS naming hierarchy, and in particular from the
   coordinated root servers of the global DNS naming hierarchy.

1.  Detailed Explanation

   There are several distinct reasons why the DNS requires a single root
   in order to operate properly.

1.1.  Maintenance of a Common Symbol Set

   Effective communications between two parties requires two essential
   preconditions:

IAB                          Informational                      [Page 1]
RFC 2826      IAB Technical Comment on the Unique DNS Root      May 2000

   -  The existence of a common symbol set, and

   -  The existence of a common semantic interpretation of these
      symbols.

   Failure to meet the first condition implies a failure to communicate
   at all, while failure to meet the second implies that the meaning of
   the communication is lost.

   In the case of a public communications system this condition of a
   common symbol set with a common semantic interpretation must be
   further strengthened to that of a unique symbol set with a unique
   semantic interpretation.  This condition of uniqueness allows any
   party to initiate a communication that can be received and understood
   by any other party.  Such a condition rules out the ability to define
   a symbol within some bounded context.  In such a case, once the
   communication moves out of the context of interpretation in which it
   was defined, the meaning of the symbol becomes lost.

   Within public digital communications networks such as the Internet
   this requirement for a uniquely defined symbol set with a uniquely
   defined meaning exists at many levels, commencing with the binary
   encoding scheme, extending to packet headers and payload formats and
   the protocol that an application uses to interact.  In each case a
   variation of the symbol set or a difference of interpretation of the
   symbols being used within the interaction causes a protocol failure,
   and the communication fails.  The property of uniqueness allows a
   symbol to be used unambiguously in any context, allowing the symbol
   to be passed on, referred to, and reused, while still preserving the
   meaning of the original use.

   The DNS fulfills an essential role within the Internet protocol
   environment, allowing network locations to be referred to using a
   label other than a protocol address.  As with any other such symbol
   set, DNS names are designed to be globally unique, that is, for any
   one DNS name at any one time there must be a single set of DNS
   records uniquely describing protocol addresses, network resources and
   services associated with that DNS name.  All of the applications
   deployed on the Internet which use the DNS assume this, and Internet
   users expect such behavior from DNS names.  Names are then constant
   symbols, whose interpretation does not specifically require knowledge
   of the context of any individual party.  A DNS name can be passed
   from one party to another without altering the semantic intent of the
   name.

   Since the DNS is hierarchically structured into domains, the
   uniqueness requirement for DNS names in their entirety implies that
   each of the names (sub-domains) defined within a domain has a unique

IAB                          Informational                      [Page 2]
RFC 2826      IAB Technical Comment on the Unique DNS Root      May 2000

   meaning (i.e., set of DNS records) within that domain.  This is as
   true for the root domain as for any other DNS domain.  The