Dynamic Host Configuration Protocol Option for Coordinate-based Location Configuration Information
RFC 3825

Network Working Group                                            J. Polk
Request for Comments: 3825                                 J. Schnizlein
Category: Standards Track                                     M. Linsner
                                                           Cisco Systems
                                                               July 2004

             Dynamic Host Configuration Protocol Option for
          Coordinate-based Location Configuration Information

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2004).

Abstract

   This document specifies a Dynamic Host Configuration Protocol Option
   for the coordinate-based geographic location of the client.  The
   Location Configuration Information (LCI) includes latitude,
   longitude, and altitude, with resolution indicators for each.  The
   reference datum for these values is also included.

Polk, et al.                Standards Track                     [Page 1]
RFC 3825             DHCP Option for Coordinate LCI            July 2004

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
       1.1.  Conventions  . . . . . . . . . . . . . . . . . . . . . .  3
       1.2.  Motivation . . . . . . . . . . . . . . . . . . . . . . .  3
       1.3.  Rationale  . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Location Configuration Information (LCI) Elements. . . . . . .  4
       2.1.  Elements of the Location Configuration Information . . .  5
   3.  Security Considerations. . . . . . . . . . . . . . . . . . . .  8
   4.  IANA Considerations. . . . . . . . . . . . . . . . . . . . . .  8
   5.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .  9
   Appendix Calculations of Imprecision possible with the DHC LCI . . 10
       A.1.  LCI of "White House" (Example 1) . . . . . . . . . . . . 10
       A.2.  LCI of "Sears Tower" (Example 2) . . . . . . . . . . . . 12
   6.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
       6.1.  Normative References . . . . . . . . . . . . . . . . . . 13
       6.2.  Informational References . . . . . . . . . . . . . . . . 14
   7.  Author Information . . . . . . . . . . . . . . . . . . . . . . 14
   8.  Full Copyright Statement . . . . . . . . . . . . . . . . . . . 15

1.  Introduction

   This document specifies a Dynamic Host Configuration Protocol [1]
   Option for the coordinate-based geographic location of the client, to
   be provided by the server.

   The DHCP server is assumed to have determined the location from the
   Circuit-ID Relay Agent Information Option (RAIO) defined (as SubOpt
   1) in [2].  In order to translate the circuit (switch port
   identifier) into a location, the DHCP server is assumed to have
   access to a service that maps from circuit-ID to the location at
   which the circuit connected to that port terminates in the building,
   for example, the location of the wall jack.

   An important feature of this specification is that after the relevant
   DHC exchanges have taken place, the location information is stored on
   the end device rather than somewhere else, where retrieving it might
   be difficult in practice.

   Another important feature of this LCI is its inclusion of a
   resolution parameter for each of the dimensions of location.  Because
   this resolution parameter need not apply to all dimensions equally, a
   resolution value is included for each of the 3 location elements.

   Resolution does not define Geographic Privacy policy.

Polk, et al.                Standards Track                     [Page 2]
RFC 3825             DHCP Option for Coordinate LCI            July 2004

   The resulting location information using this resolution method is a
   small fixed length Configuration Information that can be easily
   carried in protocols, such as DHCP, which have limited packet size
   because this LCI is only 18 bytes long.

   Finally, the appendix of this document provides some arithmetic
   examples of the implication of different resolution values on the
   La/Lo/Alt.

1.1.  Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this