A Means for Expressing Location Information in the Domain Name System
RFC 1876

Document Type RFC - Experimental (January 1996; No errata)
Updates RFC 1034, RFC 1035
Was draft-davis-dns-loc (individual)
Authors Ian Dickinson  , Paul Vixie  , Christopher Davis  , Tim Goodwin 
Last updated 2013-03-02
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Network Working Group                                           C. Davis
Request for Comments: 1876                             Kapor Enterprises
Updates: 1034, 1035                                             P. Vixie
Category: Experimental                                 Vixie Enterprises
                                                              T. Goodwin
                                                            FORE Systems
                                                            I. Dickinson
                                                   University of Warwick
                                                            January 1996

 A Means for Expressing Location Information in the Domain Name System

Status of this Memo

   This memo defines an Experimental Protocol for the Internet
   community.  This memo does not specify an Internet standard of any
   kind.  Discussion and suggestions for improvement are requested.
   Distribution of this memo is unlimited.

1. Abstract

   This memo defines a new DNS RR type for experimental purposes.  This
   RFC describes a mechanism to allow the DNS to carry location
   information about hosts, networks, and subnets.  Such information for
   a small subset of hosts is currently contained in the flat-file UUCP
   maps.  However, just as the DNS replaced the use of HOSTS.TXT to
   carry host and network address information, it is possible to replace
   the UUCP maps as carriers of location information.

   This RFC defines the format of a new Resource Record (RR) for the
   Domain Name System (DNS), and reserves a corresponding DNS type
   mnemonic (LOC) and numerical code (29).

   This RFC assumes that the reader is familiar with the DNS [RFC 1034,
   RFC 1035].  The data shown in our examples is for pedagogical use and
   does not necessarily reflect the real Internet.

Davis, et al                  Experimental                      [Page 1]
RFC 1876            Location Information in the DNS         January 1996

2. RDATA Format

       MSB                                           LSB
      0|        VERSION        |         SIZE          |
      2|       HORIZ PRE       |       VERT PRE        |
      4|                   LATITUDE                    |
      6|                   LATITUDE                    |
      8|                   LONGITUDE                   |
     10|                   LONGITUDE                   |
     12|                   ALTITUDE                    |
     14|                   ALTITUDE                    |


VERSION      Version number of the representation.  This must be zero.
             Implementations are required to check this field and make
             no assumptions about the format of unrecognized versions.

SIZE         The diameter of a sphere enclosing the described entity, in
             centimeters, expressed as a pair of four-bit unsigned
             integers, each ranging from zero to nine, with the most
             significant four bits representing the base and the second
             number representing the power of ten by which to multiply
             the base.  This allows sizes from 0e0 (<1cm) to 9e9
             (90,000km) to be expressed.  This representation was chosen
             such that the hexadecimal representation can be read by
             eye; 0x15 = 1e5.  Four-bit values greater than 9 are
             undefined, as are values with a base of zero and a non-zero

             Since 20000000m (represented by the value 0x29) is greater
             than the equatorial diameter of the WGS 84 ellipsoid
             (12756274m), it is therefore suitable for use as a
             "worldwide" size.

HORIZ PRE    The horizontal precision of the data, in centimeters,
             expressed using the same representation as SIZE.  This is
             the diameter of the horizontal "circle of error", rather

Davis, et al                  Experimental                      [Page 2]
RFC 1876            Location Information in the DNS         January 1996

             than a "plus or minus" value.  (This was chosen to match
             the interpretation of SIZE; to get a "plus or minus" value,
             divide by 2.)

VERT PRE     The vertical precision of the data, in centimeters,
             expressed using the sane representation as for SIZE.  This
             is the total potential vertical error, rather than a "plus
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