One document matched: draft-thomson-geopriv-res-gw-lis-discovery-01.txt

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GEOPRIV                                                       M. Thomson
Internet-Draft                                        Andrew Corporation
Intended status: Informational                                 R. Bellis
Expires: December 5, 2009                                     Nominet UK
                                                            June 3, 2009


  Location Information Server (LIS) Discovery From Behind Residential
                                Gateways
             draft-thomson-geopriv-res-gw-lis-discovery-01

Status of This Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
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   This Internet-Draft will expire on December 5, 2009.

Copyright Notice

   Copyright (c) 2009 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 in effect on the date of
   publication of this document (http://trustee.ietf.org/license-info).
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.

Abstract

   The residential gateway is an device that has become an integral part



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   of home networking equipment.  Discovering a Location Information
   Server (LIS) is a necessary part of aquiring location information for
   location-based services.  However, discovering a LIS when a
   residential gateway is present poses a configuration challenge,
   requiring a method that is able to work around the obstacle presented
   by the gateway.

   This document describes an interim UNilateral Self-Address Fixing
   (UNSAF) solution to this problem.  The solution provides alternative
   domain names as input to the LIS discovery process based on the IP
   addresses assigned to a Device.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Conventions used in this document  . . . . . . . . . . . . . .  4
   3.  Problem Statement  . . . . . . . . . . . . . . . . . . . . . .  4
     3.1.  Residential Gateway  . . . . . . . . . . . . . . . . . . .  6
     3.2.  Use of Discovery for Third Party Queries . . . . . . . . .  7
     3.3.  Additional and Optional Constraints  . . . . . . . . . . .  7
   4.  IP-based DNS Solution  . . . . . . . . . . . . . . . . . . . .  8
     4.1.  Identification of IP Addresses . . . . . . . . . . . . . .  8
     4.2.  Domain Name Selection  . . . . . . . . . . . . . . . . . .  9
     4.3.  When To Use This Method  . . . . . . . . . . . . . . . . . 10
     4.4.  Necessary Assumptions and Restrictions . . . . . . . . . . 10
     4.5.  Failure Modes  . . . . . . . . . . . . . . . . . . . . . . 11
     4.6.  Deployment Considerations  . . . . . . . . . . . . . . . . 11
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 11
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 12
   7.  IAB Considerations . . . . . . . . . . . . . . . . . . . . . . 12
   8.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 14
     9.2.  Informative References . . . . . . . . . . . . . . . . . . 15

















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1.  Introduction

   A Location Information Server (LIS) is a service provided by an
   access network.  The LIS uses knowledge of the access network
   topology and other information to generate location for Devices.
   Devices within an access network are able to acquire location
   information from a LIS.

   The relationship between a Device and an access network might be
   transient.  Configuration of the correct LIS at the Device ensures
   that accurate location information is available.  Without location
   information, some network services are not available.

   The configuration of a LIS address on a Device requires some
   automated configuration process.  This is particularly relevant when
   it is considered that Devices might move between different access
   networks.  LIS Discovery [I-D.ietf-geopriv-lis-discovery] describes a
   method that employs the Dynamic Host Configuration Protocol (DHCPv4
   [RFC2131], DHCPv6 [RFC3315]) as input to U-NAPTR ([RFC4848])
   discovery.

   A residential gateway, or home router, provides a range of networking
   functions for Devices within the network it serves.  In most cases,
   these functions effectively prevent the successful use of DHCP for
   LIS discovery.

   The drawback with DHCP is that universal deployment of a new option
   takes a considerable amount of time.  Often, networking equipment
   needs to be updated in order to support the new option.  Of
   particular concern are the millions of residential gateway devices
   used to provide Internet access to homes and businesses.  While
   [I-D.ietf-geopriv-lis-discovery] describes functions that can be
   provided by residential gateways to support LIS discovery, gateways
   built before the publication of this specification do not (and
   cannot) provide these functions.

   This document explores the problem of configuring Devices with a LIS
   address when a residential gateway is interposed between the Device
   and access network.  Section 3 defines the problem and Section 4
   describes a method for determining a domain name that can be used for
   discovery of the LIS.

   The solution described in this document is based on an UNilateral
   Self-Address Fixing (UNSAF) [RFC3424] method.  As such, this solution
   is considered transitional until such time as the recommendations for
   residential gateways in [I-D.ietf-geopriv-lis-discovery] are more
   widely deployed.  Considerations relating to UNSAF applications are
   described in Section 7.



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2.  Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

   This document uses terminology established in [RFC3693] and
   [I-D.ietf-ecrit-requirements].

3.  Problem Statement

   Figure 1 shows a simplified network topology for fixed wireline
   Internet access.  This arrangement is typical when wired Internet
   access is provided.  The diagram shows two network segments: the
   access network provided by an internet service provider (ISP), and
   the residential network served by the residential gateway.

   There are a number of variations on this arrangement, as documented
   in Section 3.1 of [I-D.ietf-geopriv-l7-lcp-ps].  In each of these
   variations, the consequences are the same: the goal of LIS discovery
   in this scenario is to identify the LIS in the access network.






























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                    ________
                  (/        \)
                 (( Internet ))
                  (\________/)
                       |
                       |
                 .- - -|- - - - - - - - - - - -.
                (      |                        )
               (   +--------+       +-------+    )
     Access    (   | Access |. . . .|  LIS  |    )
     Network   (   |  Node  |       |       |    )
      (ISP)    (   +--------+       +-------+    )
                (       \               \       )
                 `- - - -\- - - - - - - -\- - -'
                          \               \
                           \               |
                  .- - - - -\- - - - - - - + -.
                 (           \             |   )
                (      +-------------+     :    )
                (      | Residential |     |    )
    Residential (      |   Gateway   |     :    )
      Network   (      +-------------+     |    )
                (         /        \      /     )
                (        /          \    /      )
                (   +--------+    +--------+    )
                (   | Device |    | Device |    )
                (   +--------+    +--------+    )
                 (                             )
                  `- - - - - - - - - - - - - -'

                   Figure 1: Simplified Network Topology

   A particularly important characteristic of this arrangement is the
   relatively small area served by the residential gateway.  Given a
   small enough area, it is reasonable to delegate the responsibility
   for providing Devices within the residential network with location
   information to the ISP.  The ISP is able to provide location
   information that identifies the residence, which could be adequate
   for a range of purposes.

   A residential network that covers a larger area might require a
   dedicated LIS, a case that is outside the scope of this document.

   The goal of LIS discovery is to identify a LIS that is able to
   provide the Device with accurate location information.  In the
   network topology described, this means identifying the LIS in the
   access network.  The residential gateway is a major obstacle in
   achieving this goal.



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   R1.  An alternative method for LIS discovery MUST be provided such
        that a Device is able to successfully discover a LIS when a
        residential gateway exists between the Device and the access
        network providing the LIS.

3.1.  Residential Gateway

   A residential gateway can encompass several different functions
   including: modem, Ethernet switch, wireless access point, router,
   network address translation (NAT), DHCP server, DNS relay and
   firewall.  Of the common functions provided, the NAT function of a
   residential gateway has the greatest impact on LIS discovery.

   An ISP is typically parsimonious about their IP address allocations;
   each customer is allocated a limited number of IP addresses.
   Therefore, NAT is an extremely common function of gateways.  NAT
   enables the use of multiple Devices within the residential network
   and it could be argued that such widespread use of NAT has delayed
   the inevitable exhaustion of the IPv4 address pool.  However, NAT
   also means that Devices within the residence are not configured by
   the ISP directly.

   When it comes to discovering a LIS, the fact that Devices are not
   configured by the ISP causes a significant problem.  Configuration is
   the ideal method of conveying the information necessary for
   discovery.  Devices attached to residential gateways are usually
   given a generic configuration that includes no information about the
   ISP network.  For instance, DNS configuration typically points to a
   DNS relay on the gateway device.  This approach ensures that the
   local network served by the gateway is able to operate without a
   connectionto the ISP, but it also means that Devices are effectively
   ignorant of the ISP network.

   [I-D.ietf-geopriv-lis-discovery] describes several methods that can
   be applied by a residential gateway to assist Devices in acquiring
   location information.  For instance, the residential gateway could
   forward LIS address information to hosts within the network it
   serves.  Such an active involvement in the discovery process only
   works for new residential gateway devices that implement these
   recommendations.

   Where residential gateways already exist, direct involvement of the
   gateway in LIS discovery requires that the residential gateway be
   updated or replaced.  The cost of replacement is difficult to justify
   to the owner of the gateway.  Especially when it is considered that
   the gateway still fills its primary function: Internet access.

   Existing residential gateways have proven to be quite reliable



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   devices, some operating continuously for many years without failure.
   As a result, there are many operational gateways that are a
   considerable age, some well outside the period of manufacturer
   support.  Updating the software in such devices is not feasible in
   many cases.  Even if software updates were made available, many
   residential gateways cannot be updated remotely, inevitably leading
   to some proportion that is not updated.

   R2.  The alternative LIS discovery method MUST be able to
        successfully discover a LIS without any assistance from a
        residential gateway.

3.2.  Use of Discovery for Third Party Queries

   It is desirable that any discovery mechanism is able to be used by
   hosts outside of the access network.  This facilitates third party
   queries (see [I-D.winterbottom-geopriv-held-identity-extensions]) by
   enabling identification of the correct LIS to ask.

   In some jurisdictions, interim solutions for emergency services
   require that a voice service provider (VSP) or public safety
   answering point (PSAP) be able to request location information from
   the access network provider.  These architectures mandate third party
   queries to accomodate calling devices that are unable to acquire
   location information and convey ([I-D.ietf-sip-location-conveyance])
   that information with call signalling.

   Additional methods for third parties to determine the correct LIS to
   query are possible.  Within the confines of a particular
   jurisdiction, it is more feasible to coordinate such things as
   national ISP databases, which are one potential solution to this
   problem.  However, if a discovery solution also enabled third party
   discovery, that would be a distinct advantage of that solution.

   R3.  The alternative LIS discovery method MAY provide a means for a
        third party to discover a LIS based on the identity of a
        particular device.

   A network that is able to guarantee availability of DHCP does not
   need to provide a secondary discovery capability for the benefit of
   the Devices within the network.  However, if third party requests are
   desired, the supplementary discovery method could still be provided
   for the benefit of those third parties.

3.3.  Additional and Optional Constraints

   Certain other properties of residential gateways constrain the
   potential solutions to this problem.



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   Operation of a network firewall function is often provided by
   residential gateways as a security measure.  Security features like
   intrusion detection systems help protect users from attacks.
   Amoungst these protections is a port filter that prevents both
   inbound and outbound traffic on certain TCP and UDP ports.
   Therefore, any solution needs to consider the likelihood of traffic
   being blocked.

4.  IP-based DNS Solution

   LIS discovery [I-D.ietf-geopriv-lis-discovery] uses a DNS-based
   Dynamic Delegation Discovery Service (DDDS) system as the basis of
   discovery.  Input to this process is a domain name.  Use of DHCP for
   acquiring the domain name is specified, but alternative methods of
   acquisition are permitted.

   This document specifies a means for a device to discover several
   alternative domain names that can be used as input to the DDDS
   process.  These domain names are based on the IP address of the
   Device.  Specifically, the domain names are a portion of the reverse
   DNS trees - either the ".in-addr.arpa." or ".ip6.arpa." tree.

   A Device might be reachable at one of a number of IP addresses.  In
   the process described, a Device first identifies each IP address that
   it is potentially reachable from.  From each of these addresses, the
   Device then selects up to three domain names for use in discovery.
   These domain names are then used as input to the DDDS process.

4.1.  Identification of IP Addresses

   A Device identifies a set of potential IP addresses that currently
   result in packets being routed to it.  These are ordered by
   proximity, with those addresses that are used in adjacent network
   segments being favoured over those used in public or remote networks.
   The first addresses in the set are those that are assigned to local
   network interfaces.

   A Device can use the Session Traversal Utilities for NAT (STUN)
   [RFC5389] to determine its public reflexive transport address.  The
   host uses the "Binding Request" message and the resulting
   "XOR-MAPPED-ADDRESS" parameter that is returned in the response.

   Alternative methods for determining other IP addresses MAY be used by
   the host.  Universal Plug and Play (UPnP) [UPnP-IGD-WANIPConnection1]
   and NAT Port Mapping Protocol (NAT-PMP) [I-D.cheshire-nat-pmp] are
   both able to provide the external address of a residential gateway
   device when enabled.  These as well as proprietary methods for
   determining other addresses might also be available.  Because there



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   is no assurance that these methods will be supported by any access
   network these methods are not mandated.  Note also that in some
   cases, methods that rely on the view of the network from the
   residential gateway device could reveal an address in a private
   address range (see Section 4.4).

   In many instances, the IP address produced might be from a private
   address range.  For instance, the address on a local network
   interface could be from a private range allocated by the residential
   gateway.  In other cases, methods that rely on the view of the
   network (UPnP, NAT-PMP) from the residential gateway device could
   reveal an address in a private address range if the access network
   also uses NAT.  For a private IP address, the derived domain name is
   only usable where the DNS server used contains data for the
   corresponding private IP address range.

4.2.  Domain Name Selection

   The domain name selected for each resulting IP address is the name
   that would be used for a reverse DNS lookup.  The domain name derived
   from an IP version 4 address is in the ".in-addr.arpa." tree and
   follows the construction rules in Section 3.5 of [RFC1035].  The
   domain name derived from an IP version 6 address is in the
   ".ip6.arpa." tree and follows the construction rules in Section 2.5
   of [RFC3596].

   Additional domain names are added to allow for a single record to
   cover a larger set of addresses.  If the search on the domain derived
   from the full IP address does not produce a NAPTR record with the
   desired service tag (e.g., "LIS:HELD"), a similar search is repeated
   based on a shorter domain name, using a part of the IP address:

   o  For IP version 4, the resulting domain name SHOULD be shortened by
      one or two labels and the query repeated.  This corresponds to a
      search on a /24 or /16 network prefix.  This allows for fewer DNS
      records in the case where a single access network covering an
      entire /24 or /16 network is served by the same LIS.

   o  For IP version 6, the resulting domain SHOULD be shortened by
      either 16 or 20 labels and the query repeated.  This corresponds
      to a search on a /64 or /48 network prefix.

   DNS queries on other prefixes than those listed above SHOULD NOT be
   performed to limit the number of DNS queries performed by Devices.
   If no LIS is discovered by this method, three U-NAPTR resolutions are
   invoked for each IP address.





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4.3.  When To Use This Method

   The DHCP method described in [I-D.ietf-geopriv-lis-discovery] SHOULD
   be attempted on all local network interfaces before attempting this
   method.  This method is employed either because DHCP is unavailable,
   when the DHCP server does not provide a value for the access network
   domain name option, or if a request to the resulting LIS results in a
   HELD "notLocatable" error or equivalent.

   This method can also be used to facilitate third party queries, as
   described in Section 3.2.  Based on a known IP address, the LIS that
   serves that address can be identified as long as the corresponding
   NAPTR records are provided.

4.4.  Necessary Assumptions and Restrictions

   This is an UNSAF application and is subject to the limitations
   described in [RFC3424].

   It is not necessary that the IP address used is unique to the Device,
   only that the address can be somehow related to the Device or the
   access network that serves the Device.  This allows a degree of
   flexibility in determining this value, although security
   considerations (Section 6) might require that the address be verified
   to prevent falsification.

   Addresses from private address space [RFC1918] MAY be used as input
   to this method.  However, it is assumed that a DNS server with a view
   of the same address realm is used in order to provide the
   corresponding DNS mappings; the public DNS does not contain useful
   records for all possible address realms.

   This does not preclude the use of private address spaces; use of a
   private address space in discovery can provide an access network
   operator more granular control over discovery.  This assumes that the
   DNS server used in the U-NAPTR resolution is able to view the address
   realm.  Addresses from the public address space are more likely to be
   able to be resolved by any DNS server.  Thus, use of the public
   reflexive transport addresses acquired from a STUN server provide
   better chance of the DNS server being able to produce a usable
   result.  Ideally, the address realm Therefore, access to a STUN
   server that is able to view addresses from the public Internet is
   necessary.

   This solution assumes that the public reflexive transport address
   used by a Device is in some way controlled by their ISP, or some
   other related party.  This imples that the corresponding
   ".in-addr.arpa." or ".ip6.arpa." record can be updated by that entity



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   to include a useful value for the LIS address.

4.5.  Failure Modes

   Successful use of private addresses relies on a DNS server that is
   able to see the private address space; therefore, a means to
   determine a public IP address is necessary.  This document relies on
   STUN to provide the Device with a public reflexive transport address.
   Configuration of STUN server is necessary to ensure that this is
   successful.

   Alternative methods for discovering external IP addresses are
   possible, including UPnP and NAT-PMP.  However, these methods might
   not be enabled on the residential gateway; thus, these methods cannot
   be relied upon.

   In cases where a virtual private network (VPN) or other tunnel is
   used, the entity providing a public IP address might not be able to
   provide the Device with location information.  It is assumed that
   this entity is able to identify this problem and indicate this to the
   Device (using the "notLocatable" HELD error, or similar).  This
   problem is described in more detail in
   [I-D.ietf-geopriv-http-location-delivery].

4.6.  Deployment Considerations

   An access network provider SHOULD provide NAPTR records for each
   public IP address that is used for Devices within the access network.
   If the access network provider uses NAT, any DNS internal to that NAT
   SHOULD also include records for the private address range.

   NAPTR records can be provided for individual IP addresses.  To limit
   the proliferation of identical records, a single record can be placed
   at a the higher nodes of the tree (corresponding to /24 and /16 for
   IPv4, /64 abnd /48 for IPv6).  A record at a higher point in the tree
   (those with a shorter prefix) applies to all addresses lower in the
   tree (those with a longer prefix); records at the lower point
   override those at higher points, allowing for exceptions to be
   provided for at the lower point.

5.  IANA Considerations

   [RFC Editor: please remove this section prior to publication.]

   This document has no IANA actions.






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6.  Security Considerations

   The security considerations described in
   [I-D.ietf-geopriv-lis-discovery] apply to the discovery process as a
   whole.  In addition to those considerations, this document introduces
   further security considerations relating to the identification of the
   IP address.  It is possible that an attacker could attempt to mislead
   a Device about its IP addresses in an attempt to subvert the rest of
   the process.

   [RFC5389] describes attacks where an attacker is able to ensure that
   a Device receives a falsified reflexive address.  Even if the STUN
   server is trusted, an attacker might be able to ensure that a
   falsified address is provided to the Device.

   This attack is an effective means of denial of service, or a means to
   provide a deliberately misleading service.  Notably, any LIS that is
   identified based on a falsified IP address could still be a valid LIS
   for the given IP address, just not one that is useful for providing
   the Device with location information.  In this case, the LIS provides
   a HELD "notLocatable" error, or an equivalent.  If the falsified IP
   address is under the control of the attacker, it is possible that
   misleading (but verifiable) DNS records could indicate a malicious
   LIS that provides false location information.

   In all cases of falsification, the best remedy is to perform some
   form of independent verification of the result.  No specific
   mechanism is currently available to prevent attacks based on
   falsification of reflexive addresses; it is suggested that Devices
   attempt to independently verify that the reflexive transport address
   provided is accurate.  [[TBD - it's clear why this is called UNSAF.
   What, if any, mechanism is required here.]]

   Use of private address space effectively prevents use of the usual
   set of trust anchors for DNSSEC.  Only a DNS server that is able to
   see the same private address space can provide useful records.  A
   Device that relies on DNS records in the private address space
   portion of the ".in-addr.arpa." or ".ip6.arpa." trees MUST either use
   an alternative trust anchor for these records or rely on other means
   of ensuring the veracity of the DNS records.

7.  IAB Considerations

   The IAB has studied the problem of Unilateral Self-Address Fixing
   (UNSAF) [RFC3424], which is the general process by which a client
   attempts to determine its address in another realm on the other side
   of a NAT through a collaborative protocol reflection mechanism, such
   as STUN.



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   The IAB requires that protocol specifications that define UNSAF
   mechanisms document a set of considerations.

   1.  Precise definition of a specific, limited-scope problem that is
       to be solved with the UNSAF proposal.

       Section 3 describes the limited scope of the problem addressed in
       this document.

   2.  Description of an exit strategy/transition plan.

       [I-D.ietf-geopriv-lis-discovery] describes behaviour that
       residential gateways require in order for this short term
       solution to be rendered unnecessary.  When widespread
       implementation of the recommendations in LIS discovery, this
       UNSAF mechanism can be made obsolete.  Alternatively, this
       mechanism can be made obsolete by widespread use of
       [I-D.ietf-dhc-container-opt].

   3.  Discussion of specific issues that may render systems more
       "brittle".

       A description of the necessary assumptions and limitations of
       this solution are included in Section 4.4.

       Use of STUN for discovery of a reflexive transport address is
       inherently brittle in the presence of multiple NATs or address
       realms.  In particular, brittleness is added by the requirement
       of using a DNS server that is able to view the address realm that
       contains the IP address in question.  If address realms use
       overlapping addressing space, then there is a risk that the DNS
       server provides information that is not useful to the Device.

   4.  Identify requirements for longer term, sound technical solutions;
       contribute to the process of finding the right longer term
       solution.

       A longer term solution is already provided in
       [I-D.ietf-geopriv-lis-discovery].  However, that solution relies
       on widespread deployment.  The UNSAF solution provided here is
       provided as an interim solution that enables LIS access for
       Devices that are not able to benefit from deployment of the
       recommendations in [I-D.ietf-geopriv-lis-discovery].

   5.  Discussion of the impact of the noted practical issues with
       existing deployed NATs and experience reports.

       The UNSAF mechanism depends on the experience in deployment of



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       STUN [RFC5389].  On the whole, existing residential gateway
       devices are able to provide access to STUN and DNS service
       reliably, although support of DNSSEC is largely quite poor
       ([I-D.ietf-dnsext-dnsproxy]).

8.  Acknowledgements

   The solution in Section 4 can be largely attributed to Ray Bellis,
   who should be listed as an author.

9.  References

9.1.  Normative References

   [RFC1035]                                            Mockapetris, P.,
                                                        "Domain names -
                                                        implementation
                                                        and
                                                        specification",
                                                        STD 13,
                                                        RFC 1035,
                                                        November 1987.

   [RFC2119]                                            Bradner, S.,
                                                        "Key words for
                                                        use in RFCs to
                                                        Indicate
                                                        Requirement
                                                        Levels", BCP 14,
                                                        RFC 2119,
                                                        March 1997.

   [RFC3424]                                            Daigle, L. and
                                                        IAB, "IAB
                                                        Considerations
                                                        for UNilateral
                                                        Self-Address
                                                        Fixing (UNSAF)
                                                        Across Network
                                                        Address
                                                        Translation",
                                                        RFC 3424,
                                                        November 2002.

   [RFC3596]                                            Thomson, S.,
                                                        Huitema, C.,
                                                        Ksinant, V., and
                                                        M. Souissi, "DNS



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                                                        Extensions to
                                                        Support IP
                                                        Version 6",
                                                        RFC 3596,
                                                        October 2003.

   [I-D.ietf-geopriv-http-location-delivery]            Barnes, M.,
                                                        Winterbottom,
                                                        J., Thomson, M.,
                                                        and B. Stark,
                                                        "HTTP Enabled
                                                        Location
                                                        Delivery
                                                        (HELD)", draft-
                                                        ietf-geopriv-
                                                        http-location-
                                                        delivery-14
                                                        (work in
                                                        progress),
                                                        May 2009.

   [I-D.ietf-geopriv-lis-discovery]                     Thomson, M. and
                                                        J. Winterbottom,
                                                        "Discovering the
                                                        Local Location
                                                        Information
                                                        Server (LIS)", d
                                                        raft-ietf-
                                                        geopriv-lis-
                                                        discovery-11
                                                        (work in
                                                        progress),
                                                        May 2009.

9.2.  Informative References

   [RFC1918]                                            Rekhter, Y.,
                                                        Moskowitz, R.,
                                                        Karrenberg, D.,
                                                        Groot, G., and
                                                        E. Lear,
                                                        "Address
                                                        Allocation for
                                                        Private
                                                        Internets",
                                                        BCP 5, RFC 1918,
                                                        February 1996.




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   [RFC2131]                                            Droms, R.,
                                                        "Dynamic Host
                                                        Configuration
                                                        Protocol",
                                                        RFC 2131,
                                                        March 1997.

   [RFC3315]                                            Droms, R.,
                                                        Bound, J., Volz,
                                                        B., Lemon, T.,
                                                        Perkins, C., and
                                                        M. Carney,
                                                        "Dynamic Host
                                                        Configuration
                                                        Protocol for
                                                        IPv6 (DHCPv6)",
                                                        RFC 3315,
                                                        July 2003.

   [RFC3693]                                            Cuellar, J.,
                                                        Morris, J.,
                                                        Mulligan, D.,
                                                        Peterson, J.,
                                                        and J. Polk,
                                                        "Geopriv
                                                        Requirements",
                                                        RFC 3693,
                                                        February 2004.

   [RFC4848]                                            Daigle, L.,
                                                        "Domain-Based
                                                        Application
                                                        Service Location
                                                        Using URIs and
                                                        the Dynamic
                                                        Delegation
                                                        Discovery
                                                        Service (DDDS)",
                                                        RFC 4848,
                                                        April 2007.

   [RFC5389]                                            Rosenberg, J.,
                                                        Mahy, R.,
                                                        Matthews, P.,
                                                        and D. Wing,
                                                        "Session
                                                        Traversal
                                                        Utilities for



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                                                        NAT (STUN)",
                                                        RFC 5389,
                                                        October 2008.

   [I-D.ietf-geopriv-l7-lcp-ps]                         Tschofenig, H.
                                                        and H.
                                                        Schulzrinne,
                                                        "GEOPRIV Layer 7
                                                        Location
                                                        Configuration
                                                        Protocol;
                                                        Problem
                                                        Statement and
                                                        Requirements", d
                                                        raft-ietf-
                                                        geopriv-l7-lcp-
                                                        ps-09 (work in
                                                        progress),
                                                        February 2009.

   [I-D.ietf-ecrit-requirements]                        Schulzrinne, H.
                                                        and R. Marshall,
                                                        "Requirements
                                                        for Emergency
                                                        Context
                                                        Resolution with
                                                        Internet
                                                        Technologies", d
                                                        raft-ietf-ecrit-
                                                        requirements-13
                                                        (work in
                                                        progress),
                                                        March 2007.

   [I-D.ietf-sip-location-conveyance]                   Polk, J. and B.
                                                        Rosen, "Location
                                                        Conveyance for
                                                        the Session
                                                        Initiation
                                                        Protocol", draft
                                                        -ietf-sip-
                                                        location-
                                                        conveyance-13
                                                        (work in
                                                        progress),
                                                        March 2009.

   [UPnP-IGD-WANIPConnection1]                          UPnP Forum,



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                                                        "Internet
                                                        Gateway Device
                                                        (IGD)
                                                        Standardized
                                                        Device Control
                                                        Protocol V 1.0:
                                                        WANIPConnection:
                                                        1 Service
                                                        Template Version
                                                        1.01 For UPnP
                                                        Version 1.0",
                                                        DCP 05-001,
                                                        Nov 2001.

   [I-D.cheshire-nat-pmp]                               Cheshire, S.,
                                                        "NAT Port
                                                        Mapping Protocol
                                                        (NAT-PMP)", draf
                                                        t-cheshire-nat-
                                                        pmp-03 (work in
                                                        progress),
                                                        April 2008.

   [I-D.cheshire-dnsext-multicastdns]                   Cheshire, S. and
                                                        M. Krochmal,
                                                        "Multicast DNS",
                                                        draft-cheshire-
                                                        dnsext-
                                                        multicastdns-07
                                                        (work in
                                                        progress),
                                                        September 2008.

   [I-D.winterbottom-geopriv-held-identity-extensions]  Thomson, M.,
                                                        Tschofenig, H.,
                                                        Barnes, R., and
                                                        J. Winterbottom,
                                                        "Use of Target
                                                        Identity in
                                                        HTTP-Enabled
                                                        Location
                                                        Delivery
                                                        (HELD)", draft-
                                                        winterbottom-
                                                        geopriv-held-
                                                        identity-
                                                        extensions-09
                                                        (work in



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                                                        progress),
                                                        February 2009.

   [I-D.ietf-dnsext-dnsproxy]                           Bellis, R., "DNS
                                                        Proxy
                                                        Implementation
                                                        Guidelines", dra
                                                        ft-ietf-dnsext-
                                                        dnsproxy-05
                                                        (work in
                                                        progress),
                                                        April 2009.

   [I-D.ietf-dhc-container-opt]                         Droms, R.,
                                                        "Container
                                                        Option for
                                                        Server
                                                        Configuration",
                                                        draft-ietf-dhc-
                                                        container-opt-05
                                                        (work in
                                                        progress),
                                                        March 2009.

Authors' Addresses

   Martin Thomson
   Andrew Corporation
   PO Box U40
   Wollongong University Campus, NSW  2500
   AU

   Phone: +61 2 4221 2915
   EMail: martin.thomson@andrew.com
   URI:   http://www.andrew.com/


   Ray Bellis
   Nominet UK
   Edmund Halley Road
   Oxford  OX4 4DQ
   United Kingdom

   Phone: +44 1865 332211
   EMail: ray.bellis@nominet.org.uk
   URI:   http://www.nominet.org.uk/





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