Discovering the Local Location Information Server (LIS)
RFC 5986

Internet Engineering Task Force (IETF)                        M. Thomson
Request for Comments: 5986                               J. Winterbottom
Category: Standards Track                             Andrew Corporation
ISSN: 2070-1721                                           September 2010

        Discovering the Local Location Information Server (LIS)

Abstract

   Discovery of the correct Location Information Server (LIS) in the
   local access network is necessary for Devices that wish to acquire
   location information from the network.  A method is described for the
   discovery of a LIS in the access network serving a Device.  Dynamic
   Host Configuration Protocol (DHCP) options for IP versions 4 and 6
   are defined that specify a domain name.  This domain name is then
   used as input to a URI-enabled NAPTR (U-NAPTR) resolution process.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc5986.

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Thomson & Winterbottom       Standards Track                    [Page 1]
RFC 5986                      LIS Discovery               September 2010

Table of Contents

   1.  Introduction and Overview  . . . . . . . . . . . . . . . . . .  2
     1.1.  Discovery Procedure Overview . . . . . . . . . . . . . . .  3
     1.2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  LIS Discovery Procedure  . . . . . . . . . . . . . . . . . . .  4
     2.1.  Residential Gateways . . . . . . . . . . . . . . . . . . .  6
     2.2.  Virtual Private Networks (VPNs)  . . . . . . . . . . . . .  7
   3.  Determining a Domain Name  . . . . . . . . . . . . . . . . . .  7
     3.1.  Domain Name Encoding . . . . . . . . . . . . . . . . . . .  7
     3.2.  Access Network Domain Name DHCPv4 Option . . . . . . . . .  8
     3.3.  Access Network Domain Name DHCPv6 Option . . . . . . . . .  8
     3.4.  Alternative Domain Names . . . . . . . . . . . . . . . . .  9
   4.  U-NAPTR Resolution of a LIS URI  . . . . . . . . . . . . . . . 10
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 11
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 13
     6.1.  Registration of DHCPv4 and DHCPv6 Option Codes . . . . . . 13
     6.2.  Registration of a Location Server Application Service
           Tag  . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
     6.3.  Registration of a Location Server Application Protocol
           Tag for HELD . . . . . . . . . . . . . . . . . . . . . . . 13
   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 14
     8.2.  Informative References . . . . . . . . . . . . . . . . . . 15

1.  Introduction and Overview

   The location of a Device is a useful and sometimes necessary part of
   many services.  A Location Information Server (LIS) is responsible
   for providing that location information to Devices with attached
   access networks used to provide Internet access.  The LIS uses
   knowledge of the access network and its physical topology to generate
   and serve location information to Devices.

   Each access network requires specific knowledge about topology.
   Therefore, it is important to discover the LIS that has the specific
   knowledge necessary to locate a Device, that is, the LIS that serves
   the current access network.  Automatic discovery is important where
   there is any chance of movement outside a single access network.
   Reliance on static configuration can lead to unexpected errors if a