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
datatracker.ietf.org