Internet Engineering Task Force (IETF)                     H. Tschofenig
Request for Comments: 5687                        Nokia Siemens Networks
Category: Informational                                   H. Schulzrinne
ISSN: 2070-1721                                      Columbia University
                                                             March 2010


           GEOPRIV Layer 7 Location Configuration Protocol:
                  Problem Statement and Requirements

Abstract

  This document provides a problem statement, lists requirements, and
  captures design aspects for a GEOPRIV Layer 7 (L7) Location
  Configuration Protocol (LCP).  This protocol aims to allow an end
  host to obtain location information, by value or by reference, from a
  Location Information Server (LIS) that is located in the access
  network.  The obtained location information can then be used for a
  variety of different protocols and purposes.  For example, it can be
  used as input to the Location-to-Service Translation (LoST) Protocol
  or to convey location within the Session Initiation Protocol (SIP) to
  other entities.

Status of This Memo

  This document is not an Internet Standards Track specification; it is
  published for informational purposes.

  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).  Not all documents
  approved by the IESG are a candidate for any level of Internet
  Standard; see 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/rfc5687.













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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.

Table of Contents

  1. Introduction ....................................................3
  2. Terminology .....................................................3
  3. Scenarios .......................................................4
     3.1. Fixed-Wired Environment ....................................4
     3.2. Mobile Network .............................................7
     3.3. Wireless Access ............................................8
  4. Discovery of the Location Information Server ....................9
  5. Identifier for Location Determination ..........................11
  6. Requirements ...................................................14
  7. Security Considerations ........................................16
  8. Contributors ...................................................17
  9. Acknowledgements ...............................................18
  10. References ....................................................18
     10.1. Normative References .....................................18
     10.2. Informative References ...................................18



















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1.  Introduction

  This document provides a problem statement, lists requirements, and
  captures design aspects for a GEOPRIV Layer 7 (L7) Location
  Configuration Protocol (LCP).  The protocol has two purposes:

  o  It is used by a device to obtain its own location (referred as
     "Location by Value" or LbyV) from a dedicated node, called the
     Location Information Server (LIS).

  o  It enables the device to obtain a reference to location
     information (referred as "Location by Reference" or LbyR).  This
     reference can take the form of a subscription URI, such as a SIP
     presence-based Uniform Resource Identifier (URI), an HTTP/HTTPS
     URI, or another URI.  The requirements related to the task of
     obtaining an LbyR are described in a separate document, see
     [LBYR-REQS].

  The need for these two functions can be derived from the scenarios
  presented in Section 3.

  For this document, we assume that the GEOPRIV Layer 7 LCP runs
  between the device and the LIS.

  This document is structured as follows.  Section 4 discusses the
  challenge of discovering the LIS in the access network.  Section 5
  compares different types of identifiers that can be used to retrieve
  location information.  A list of requirements for the L7 LCP can be
  found in Section 6.

  This document does not describe how the access network provider
  determines the location of the device since this is largely a matter
  of the capabilities of specific link-layer technologies or certain
  deployment environments.

2.  Terminology

  In this document, the key words "MUST", "MUST NOT", "REQUIRED",
  "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
  and "OPTIONAL" are to be interpreted as described in RFC 2119
  [RFC2119], with the qualification that unless otherwise stated these
  words apply to the design of the GEOPRIV Layer 7 Location
  Configuration Protocol.

  The term Location Information Server (LIS) refers to an entity
  capable of determining the location of a device and of providing that
  location information, a reference to it, or both via the Location
  Configuration Protocol (LCP) to the Target.



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  This document also uses terminology from [RFC5012] (such as Internet
  Access Provider (IAP), Internet Service Provider (ISP), and
  Application Service Provider (ASP)).

  With the term "Access Network Provider" we refer to the IAP and the
  ISP) without further distinguishing these two entities, as it is not
  relevant for the purpose of this document.  An additional
  requirements document on LIS-to-LIS protocol [LIS2LIS] shows a
  scenario where the separation between IAP and ISP is important.

3.  Scenarios

  This section describes a few network scenarios where the L7 LCP may
  be used.  Note that this section does not aim to exhaustively list
  all possible deployment environments.  Instead, we focus on the
  following environments:

  o  DSL/Cable networks, WiMAX-like (Worldwide Interoperability for
     Microwave Access) fixed access

  o  Airport, city, campus wireless networks, such as 802.11a/b/g,
     802.16e/WiMAX

  o  3G networks

  o  Enterprise networks

  Note that we use the term 'host' instead of device for better
  readability.

3.1.  Fixed-Wired Environment

  Figure 1 shows a Digital Subscriber Line (DSL) network scenario with
  the Access Network Provider and the customer premises.  The Access
  Network Provider operates link- and network-layer devices
  (represented as a node) and the LIS.















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  +---------------------------+
  |                           |
  |  Access Network Provider  |
  |                           |
  |   +--------+              |
  |   | Node   |              |
  |   +--------+ +----------+ |
  |       |  |   | LIS      | |
  |       |  +---|          | |
  |       |      +----------+ |
  |       |                   |
  +-------+-------------------+
          | Wired Network
  <----------------> Access Network Provider demarc
          |
  +-------+-------------------+
  |       |                   |
  |   +-------------+         |
  |   | NTE         |         |
  |   +-------------+         |
  |       |                   |
  |       |                   |
  |   +--------------+        |
  |   | Device with  | Home   |
  |   | NAPT and     | Router |
  |   | DHCP server  |        |
  |   +--------------+        |
  |       |                   |
  |       |                   |
  |    +------+               |
  |    | Host |               |
  |    +------+               |
  |                           |
  |Customer Premises Network  |
  |                           |
  +---------------------------+

  Figure 1: Fixed-Wired Scenario

  The customer premises network consists of a router with a Network
  Address Translator with Port Address Translation (NAPT) and a DHCP
  server as used in most Customer Premises Networks (CPNs) and the
  Network Termination Equipment (NTE) where Layer 1 and sometimes Layer
  2 protocols are terminated.  The router in the home network (e.g.,
  broadband router, cable or DSL router) typically runs a NAPT and a
  DHCP server.  The NTE is a legacy device and in many cases cannot be
  modified for the purpose of delivering location information to the
  host.  The same is true of the device with the NAPT and DHCP server.



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  It is possible for the NTE and the home router to physically be in
  the same box, or for there to be no home router, or for the NTE and
  host to be in the same physical box (with no home router).  An
  example of this last case is where Ethernet service is delivered to
  customers' homes, and the Ethernet network interface card (NIC) in
  their PC serves as the NTE.

  Current CPN deployments generally fall into one of the following
  classifications:

  1.  Single PC

      1.  with Ethernet network interface card (NIC), with Point-to-
          Point Protocol Over Ethernet (PPPoE), or Dynamic Host
          Configuration Protocol (DHCP) on PC; there may be a bridged
          DSL or cable modem as the NTE, or the Ethernet NIC might be
          the NTE.

      2.  with USB-based DSL access or a cable modem access using
          Point-to-Point Protocol over ATM (PPPoA), PPPoE, or DHCP on
          PC.

      Note that the device with NAPT and DHCP of Figure 1 is not
      present in such a scenario.

  2.  One or more hosts with at least one router (DHCP client or PPPoE,
      DHCP server in router; Voice over IP (VoIP) can be a soft client
      on a PC, a stand-alone VoIP device, or an Analog Terminal Adaptor
      (ATA) function embedded in a router):

      1.  combined router and NTE.

      2.  separate router with NTE in bridged mode.

      3.  separate router with NTE (NTE/router does PPPoE or DHCP to
          WAN, router provides DHCP server for hosts in LAN; double
          NAT).

  The majority of fixed-access broadband customers use a router.  The
  placement of the VoIP client is mentioned to describe what sorts of
  hosts may need to be able to request location information.  Soft
  clients on PCs are frequently not launched until long after
  bootstrapping is complete, and are not able to control any options
  that may be specified during bootstrapping.  They also cannot control
  whether a VPN client is running on the end host.






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3.2.  Mobile Network

  One example of a moving network is a WiMAX-fixed wireless scenario.
  This also applies to "pre-WiMAX" and "WiMAX-like" fixed wireless
  networks.  In implementations intended to provide broadband service
  to a home or other stationary location, the customer-side antenna/NTE
  tends to be rather small and portable.  The LAN-side output of this
  device is an Ethernet jack, which can be used to feed a PC or a
  router.  The PC or router then uses DHCP or PPPoE to connect to the
  access network, the same as for wired access networks.  Access
  providers who deploy this technology may use the same core network
  (including network elements that terminate PPPoE and provide IP
  addresses) for DSL, fiber to the premises (FTTP), and fixed wireless
  customers.

  Given that the customer antenna is portable and can be battery-
  powered, it is possible for a user to connect a laptop to it and move
  within the coverage area of a single base antenna.  This coverage
  area can be many square kilometers in size.  In this case, the laptop
  (and any SIP client running on it) would be completely unaware of
  their mobility.  Only the user and the network are aware of the
  laptop's mobility.

  Further examples of moving networks (where end devices may not be
  aware that they are moving) can be found in busses, trains, and
  airplanes.

  Figure 2 shows an example topology for a moving network.























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  +--------------------------+
  | Wireless                 |
  | Access Network Provider  |
  |                          |
  |              +----------+|
  |      +-------+ LIS      ||
  |      |       |          ||
  |  +---+----+  +----------+|
  |  | Node   |              |
  |  |        |              |
  |  +---+----+              |
  |      |                   |
  +------+-------------------+
         | Wireless Interface
         |
  +------+-------------------+
  |      |    Moving Network |
  |  +---+----+              |
  |  | NTE    |   +--------+ |
  |  |        +---+ Host   | |
  |  +-+-----++   |  B     | |
  |    |     \    +--------+ |
  |    |      \              |
  |+---+----+  \  +---+----+ |
  || Host   |   \ | Host   | |
  ||  A     |    \+  B     | |
  |+--------+     +--------+ |
  +--------------------------+

  Figure 2: Moving Network

3.3.  Wireless Access

  Figure 3 shows a wireless access network where a moving host obtains
  location information or references to location information from the
  LIS.  The access equipment uses, in many cases, link-layer devices.
  Figure 3 represents a hotspot network found, for example, in hotels,
  airports, and coffee shops.  For editorial reasons we only describe a
  single access point and do not depict how the LIS obtains location
  information since this is very deployment specific.











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  +--------------------------+
  | Access Network Provider  |
  |                          |
  |              +----------+|
  |      +-------| LIS      ||
  |      |       |          ||
  |  +--------+  +----------+|
  |  | Access |              |
  |  | Point  |              |
  |  +--------+              |
  |      |                   |
  +------+-------------------+
         |
     +------+
     | Host |
     +------+

  Figure 3: Wireless Access Scenario

4.  Discovery of the Location Information Server

     Note that this section lists mechanisms that were discussed in the
     GEOPRIV Layer 7 Location Configuration Protocol design team.  They
     are included to show challenges in the problem space and are
     listed for completeness reasons.  They do not in any way mean that
     there is consensus about any of the mechanisms or that the IETF
     recommends any of the procedures described in this section.

  When a device wants to retrieve location information from the LIS, it
  first needs to discover it.  Based on the problem statement of
  determining the location of the device, which is known best by
  entities close to the device itself, we assume that the LIS is
  located in the local subnet or in the access network.  Several
  procedures have been investigated that aim to discover the LIS in
  such an access network.

  DHCP-based Discovery:

     In some environments, the Dynamic Host Configuration Protocol
     (DHCP) might be a good choice for discovering the fully-qualified
     domain name (FQDN) or the IP address of the LIS.  In environments
     where DHCP can be used, it is also possible to use the already
     defined location extensions.  In environments with legacy devices,
     such as the one shown in Section 3.1, a DHCP-based discovery
     solution may not be possible.






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  DNS-based Discovery:

     Before a Domain Name System (DNS) lookup can be started, it is
     necessary to learn the domain name of the access network that runs
     an LIS.  Several ways to learn the domain name exist.  For
     example, the end host obtains its own public IP address via Simple
     Traversal of the UDP Protocol through NAT (STUN) [RFC5389], and
     performs a reverse DNS lookup (assuming the data is provisioned
     into the DNS).  Then, the DNS Service (SRV) record or the DNS
     Naming Authority Pointer (NAPTR) record for that domain is
     retrieved.  A more detailed description of this approach can be
     found in [LIS-DISC].

  Redirect Rule:

     A redirect rule at an entity in the access network could be used
     to redirect the L7 LCP signaling messages (destined to a specific
     port) to the LIS.  The device could then discover the LIS by
     sending a packet with a specific (registered) port number to
     almost any address as long as the destination IP address does not
     target an entity in the local network.  The packet would be
     redirected to the respective LIS being configured.  The same
     procedure is used by captive portals whereby any HTTP traffic is
     intercepted and redirected.

     To some extent, this approach is similar to packets that are
     marked with a Router Alert option [RFC2113] and intercepted by
     entities that understand the specific marking.  In the above-
     mentioned case, however, the marking is provided via a registered
     port number instead of relying on a Router Alert option.

     This solution approach would require a deep packet inspection
     capability at an entity in the access provider's networks that
     scans for the occurrence of particular destination port numbers.

  Multicast Query:

     A device could also discover an LIS by sending a DNS query to a
     well-known address.  An example of such a mechanism is multicast
     DNS (see [RFC4795] and [mDNS]).  Unfortunately, these mechanisms
     only work on the local link.










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  Anycast:

     With this solution, an anycast address is defined (for IPv4 and
     IPv6) in the style of [RFC3068] that allows the device to route
     discovery packets to the nearest LIS.  Note that this procedure
     would be used purely for discovery and is therefore similar to the
     local Teredo server discovery approach outlined in Section 4.2 of
     [TEREDO-SEL].

  The LIS discovery procedure raises deployment and security issues.
  The access network needs to be designed to prevent man-in-the-middle
  adversaries from presenting themselves as an LIS to devices.  When a
  device discovers an LIS, it needs to ensure (and be able to ensure)
  that the discovered entity is indeed an authorized LIS.

5.  Identifier for Location Determination

     Note that this section lists mechanisms that were discussed in the
     GEOPRIV Layer 7 Location Configuration Protocol design team.  They
     are included to show challenges in the problem space and are
     listed for completeness reasons.  They do not in any way mean that
     there is consensus about any of the mechanisms or that the IETF
     recommends any of the procedures described in this section.

  The LIS returns location information to the device when it receives a
  request.  Some form of identifier is therefore needed to allow the
  LIS to retrieve the device's current location, or a good
  approximation, from a database.

  The chosen identifier needs to have the following properties:

  Ability for Device to learn or know the identifier:

     The device MUST know or MUST be able to learn of the identifier
     (explicitly or implicitly) in order to send it to the LIS.
     Implicitly refers to the situation where a device along the path
     between the device and the LIS modifies the identifier, as it is
     done by a NAT when an IP address based identifier is used.

  Ability to use the identifier for location determination:

     The LIS MUST be able to use the identifier (directly or
     indirectly) for location determination.  Indirectly refers to the
     case where the LIS uses other identifiers internally for location
     determination, in addition to the one provided by the device.






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  Security properties of the identifier:

     Misuse needs to be minimized whereby an off-path adversary MUST
     NOT be able to obtain location information of other devices.  An
     on-path adversary in the same subnet SHOULD NOT be able to spoof
     the identifier of another device in the same subnet.

  The following list discusses frequently mentioned identifiers and
  their properties:

  Media Access Control (MAC) Address:

     The MAC address is known to the device itself, but not carried
     beyond a single IP hop and therefore not accessible to the LIS in
     most deployment environments (unless carried in the L7 LCP
     itself).

  Asynchronous Transfer Mode (ATM) Virtual Path Identifier / Virtual
     Circuit Identifier (VPI/VCI):

     The VCI/VPI is generally only seen by the DSL modem.  Almost all
     routers in the United States use 1 of 2 VPI/VCI value pairs: 0/35
     and 8/35.  This VC is terminated at the digital subscriber line
     access multiplexer (DSLAM), which uses a different VPI/VCI (per
     end customer) to connect to the ATM switch.  Only the network
     provider is able to map VPI/VCI values through its network.  With
     the arrival of Very high rate Digital Subscriber Line (VDSL), ATM
     will slowly be phased out in favor of Ethernet.

  Ethernet Switch (Bridge)/Port Number:

     This identifier is available only in certain networks, such as
     enterprise networks, typically available via the IEEE 802.1AB
     protocol [802.1AB] or proprietary protocols like the Cisco
     Discovery Protocol (CDP) [CDP].

  Cell ID:

     This identifier is available in cellular data networks and the
     cell ID may not be visible to the device.











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  Host Identifier:

     The Host Identifier introduced by the Host Identity Protocol (HIP)
     [RFC5201] allows identification of a particular host.
     Unfortunately, the network can only use this identifier for
     location determination if the operator already stores a mapping of
     host identities to location information.  Furthermore, there is a
     deployment problem since the host identities are not used in
     today's networks.

  Cryptographically Generated Address (CGA):

     The concept of a Cryptographically Generated Address (CGA) was
     introduced by [RFC3972].  The basic idea is to put the truncated
     hash of a public key into the interface identifier part of an IPv6
     address.  In addition to the properties of an IP address, it
     allows a proof of ownership.  Hence, a return routability check
     can be omitted.  It is only available for IPv6 addresses.

  Network Access Identifiers:

     A Network Access Identifier [RFC4282] is used during the network
     access authentication procedure, for example, in RADIUS [RFC2865]
     and Diameter [RFC3588].  In DSL networks, the user credentials
     are, in many cases, only known by the home router and not
     configured at the device itself.  To the network, the
     authenticated user identity is only available if a network access
     authentication procedure is executed.  In case of roaming, the
     user's identity might not be available to the access network since
     security protocols might offer user identity confidentiality and
     thereby hide the real identity of the user allowing the access
     network to only see a pseudonym or a randomized string.

  Unique Client Identifier

     The Broadband Forum has defined that all devices that expect to be
     managed by the TR-069 interface, see [TR069], have to be able to
     generate an identifier that uniquely identifies the device.  It
     also has a requirement that routers that use DHCP to the WAN use
     RFC 4361 [RFC4361] to provide the DHCP server with a unique client
     identifier.  This identifier is, however, not visible to the
     device when legacy NTE devices are used.









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  IP Address:

     The device's IP address may be used for location determination.
     This IP address is not visible to the LIS if the device is behind
     one or multiple NATs.  This may not be a problem since the
     location of a device that is located behind a NAT cannot be
     determined by the access network.  The LIS would in this case only
     see the public IP address of the NAT binding allocated by the NAT,
     which is the expected behavior.  The property of the IP address
     for a return routability check is attractive to return location
     information only to the address that submitted the request.  If an
     adversary wants to learn the location of a device (as identified
     by a particular IP address), then it does not see the response
     message (unless it is on the subnetwork or at a router along the
     path towards the LIS).

     On a shared medium, an adversary could ask for location
     information of another device.  The adversary would be able to see
     the response message since it is sniffing on the shared medium
     unless security mechanisms, such as link-layer encryption, are in
     place.  With a network deployment as shown in Section 3.1 with
     multiple devices in the Customer Premises being behind a NAT, the
     LIS is unable to differentiate the individual devices.  For WLAN
     deployments as found in hotels, as shown in Section 3.3, it is
     possible for an adversary to eavesdrop data traffic and
     subsequently to spoof the IP address in a query to the LIS to
     learn more detailed location information (e.g., specific room
     numbers).  Such an attack might, for example, compromise the
     privacy of hotel guests.

6.  Requirements

  The following requirements and assumptions have been identified:

  Requirement L7-1: Identifier Choice

     The L7 LCP MUST be able to carry different identifiers or MUST
     define an identifier that is mandatory to implement.  Regarding
     the latter aspect, such an identifier is only appropriate if it is
     from the same realm as the one for which the location information
     service maintains identifier-to-location mapping.










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RFC 5687            GEOPRIV L7 LCP: Problem Statement         March 2010


  Requirement L7-2: Mobility Support

     The L7 LCP MUST support a broad range of mobility from devices
     that can only move between reboots, to devices that can change
     attachment points with the impact that their IP address is
     changed, to devices that do not change their IP address while
     roaming, to devices that continuously move by being attached to
     the same network attachment point.

  Requirement L7-3: ASP and Access Network Provider Relationship

     The design of the L7 LCP MUST NOT assume that a business or trust
     relationship between the Application Service Provider (ASP) and
     the Access Network Provider.  Requirements for resolving a
     reference to location information are not discussed in this
     document.

  Requirement L7-4: Layer 2 and Layer 3 Provider Relationship

     The design of the L7 LCP MUST assume that there is a trust and
     business relationship between the L2 and the L3 provider.  The L3
     provider operates the LIS that the device queries.  It, in turn,
     needs to obtain location information from the L2 provider since
     this one is closest to the device.  If the L2 and L3 provider for
     the same device are different entities, they cooperate for the
     purposes needed to determine locations.

  Requirement L7-5: Legacy Device Considerations

     The design of the L7 LCP MUST consider legacy devices, such as
     residential NAT devices and NTEs in a DSL environment, that cannot
     be upgraded to support additional protocols, for example, to pass
     additional information towards the device.

  Requirement L7-6: Virtual Private Network (VPN) Awareness

     The design of the L7 LCP MUST assume that at least one end of a
     VPN is aware of the VPN functionality.  In an enterprise scenario,
     the enterprise side will provide the LIS used by the device and
     can thereby detect whether the LIS request was initiated through a
     VPN tunnel.










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RFC 5687            GEOPRIV L7 LCP: Problem Statement         March 2010


  Requirement L7-7: Network Access Authentication

     The design of the L7 LCP MUST NOT assume that prior network access
     authentication.

  Requirement L7-8: Network Topology Unawareness

     The design of the L7 LCP MUST NOT assume that devices are aware of
     the access network topology.  Devices are, however, able to
     determine their public IP address(es) via mechanisms, such as
     Simple Traversal of User Datagram Protocol (UDP) Through Network
     Address Translators (NATs) (STUN) [RFC5389] or Next Steps in
     Signaling (NSIS) NAT/Firewall NSIS Signaling Layer Protocol (NSLP)
     [NSLP].

  Requirement L7-9: Discovery Mechanism

     The L7 LCP MUST define a mandatory-to-implement LIS discovery
     mechanism.

  Requirement L7-10: PIDF-LO Creation

     When an LIS creates a Presence Information Data Format (PIDF)
     Location Object (LO) [RFC4119], then it MUST put the <geopriv>
     element into the <device> element of the presence document (see
     [RFC4479]).  This ensures that the resulting PIDF-LO document,
     which is subsequently distributed to other entities, conforms to
     the rules outlined in [RFC5491].

7.  Security Considerations

  By using a Geolocation L7 Location Configuration Protocol, the device
  (and a human user of such a device, if applicable) exposes themselves
  to a privacy risk whereby an unauthorized entity receives location
  information.  Providing confidentiality protected location to the
  requestor depends on the success of four steps:

  1.  The client MUST have a means to discover a LIS.

  2.  The client MUST authenticate the discovered LIS.

  3.  The LIS MUST be able to determine location and return it to the
      authorized entity.

  4.  The LIS MUST securely exchange messages without intermediaries
      eavesdropping or tampering with them.





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RFC 5687            GEOPRIV L7 LCP: Problem Statement         March 2010


  This document contains various security-related requirements
  throughout the document addressing the above-mentioned steps.  For a
  broader security discussion of the overall geolocation privacy
  architecture, the reader is referred to [GEOPRIV-ARCH].

8.  Contributors

  This contribution is a joint effort of the GEOPRIV Layer 7 Location
  Configuration Requirements Design Team of the IETF GEOPRIV Working
  Group.  The contributors include Henning Schulzrinne, Barbara Stark,
  Marc Linsner, Andrew Newton, James Winterbottom, Martin Thomson,
  Rohan Mahy, Brian Rosen, Jon Peterson, and Hannes Tschofenig.

  We would like to thank the GEOPRIV Working Group Chairs, Andy Newton,
  Randy Gellens, and Allison Mankin, for creating the design team.
  Furthermore, we would like thank Andy Newton for his support during
  the design team mailing list, for setting up Jabber chat conferences,
  and for participating in the phone conference discussions.

  The design team members can be reached at:

  Marc Linsner:  [email protected]

  Rohan Mahy:  [email protected]

  Andrew Newton:  [email protected]

  Jon Peterson:  [email protected]

  Brian Rosen:  [email protected]

  Henning Schulzrinne:  [email protected]

  Barbara Stark:  [email protected]

  Martin Thomson:  [email protected]

  Hannes Tschofenig:  [email protected]

  James Winterbottom:  [email protected]











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RFC 5687            GEOPRIV L7 LCP: Problem Statement         March 2010


9.  Acknowledgements

  We would also like to thank Murugaraj Shanmugam, Ted Hardie, Martin
  Dawson, Richard Barnes, James Winterbottom, Tom Taylor, Otmar Lendl,
  Marc Linsner, Brian Rosen, Roger Marshall, Guy Caron, Doug Stuard,
  Eric Arolick, Dan Romascanu, Jerome Grenier, Martin Thomson, Barbara
  Stark, Michael Haberler, and Mary Barnes for their WGLC review
  comments.

  The authors would like to thank NENA for their work on [NENA] as it
  helped to provide some of the initial thinking.

  The authors would also like to thank Cullen Jennings for his feedback
  as part of the IESG processing.  Additionally, we would like to thank
  Alexey Melnikov, Dan Romascanu, and Robert Sparks.

10.  References

10.1.  Normative References

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

  [RFC5012]       Schulzrinne, H. and R. Marshall, "Requirements for
                  Emergency Context Resolution with Internet
                  Technologies", RFC 5012, January 2008.

10.2.  Informative References

  [802.1AB]       "IEEE 802.1AB-2005 IEEE Standard for Local and
                  Metropolitan Area Networks Station and Media Access
                  Control Connectivity Discovery", May 2005, <http://
                  standards.ieee.org/getieee802/download/
                  802.1AB-2005.pdf>.

  [CDP]           Wikipedia, "Cisco Discovery Protocol (CDP)", <http://
                  en.wikipedia.org/wiki/Cisco_Discovery_Protocol>.

  [GEOPRIV-ARCH]  Barnes, R., Lepinski, M., Cooper, A., Morris, J.,
                  Tschofenig, H., and H. Schulzrinne, "An Architecture
                  for Location and Location Privacy in Internet
                  Applications", Work in Progress, October 2009.

  [LBYR-REQS]     Marshall, R., Ed., "Requirements for a Location-by-
                  Reference Mechanism", Work in Progress,
                  November 2009.





Tschofenig & Schulzrinne      Informational                    [Page 18]

RFC 5687            GEOPRIV L7 LCP: Problem Statement         March 2010


  [LIS-DISC]      Thomson, M. and J. Winterbottom, "Discovering the
                  Local Location Information Server (LIS)", Work
                  in Progress, February 2010.

  [LIS2LIS]       Winterbottom, J. and S. Norreys, "LIS to LIS Protocol
                  Requirements", Work in Progress, November 2007.

  [NENA]          "NENA 08-505, Issue 1, 2006 (December 21, 2006), NENA
                  Recommended Method(s) for Location Determination to
                  Support IP-Based Emergency Services - Technical
                  Information Document (TID)", December 2006, <http://
                  www.nena.org/sites/default/files/
                  08-505_20061221.pdf>.

  [NSLP]          Stiemerling, M., Tschofenig, H., Aoun, C., and E.
                  Davies, "NAT/Firewall NSIS Signaling Layer Protocol
                  (NSLP)", Work in Progress, February 2010.

  [RFC2113]       Katz, D., "IP Router Alert Option", RFC 2113,
                  February 1997.

  [RFC2865]       Rigney, C., Willens, S., Rubens, A., and W. Simpson,
                  "Remote Authentication Dial In User Service
                  (RADIUS)", RFC 2865, June 2000.

  [RFC3068]       Huitema, C., "An Anycast Prefix for 6to4 Relay
                  Routers", RFC 3068, June 2001.

  [RFC3588]       Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and
                  J. Arkko, "Diameter Base Protocol", RFC 3588,
                  September 2003.

  [RFC3972]       Aura, T., "Cryptographically Generated Addresses
                  (CGA)", RFC 3972, March 2005.

  [RFC4119]       Peterson, J., "A Presence-based GEOPRIV Location
                  Object Format", RFC 4119, December 2005.

  [RFC4282]       Aboba, B., Beadles, M., Arkko, J., and P. Eronen,
                  "The Network Access Identifier", RFC 4282,
                  December 2005.

  [RFC4361]       Lemon, T. and B. Sommerfeld, "Node-specific Client
                  Identifiers for Dynamic Host Configuration Protocol
                  Version Four (DHCPv4)", RFC 4361, February 2006.

  [RFC4479]       Rosenberg, J., "A Data Model for Presence", RFC 4479,
                  July 2006.



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RFC 5687            GEOPRIV L7 LCP: Problem Statement         March 2010


  [RFC4795]       Aboba, B., Thaler, D., and L. Esibov, "Link-local
                  Multicast Name Resolution (LLMNR)", RFC 4795,
                  January 2007.

  [RFC5201]       Moskowitz, R., Nikander, P., Jokela, P., and T.
                  Henderson, "Host Identity Protocol", RFC 5201,
                  April 2008.

  [RFC5389]       Rosenberg, J., Mahy, R., Matthews, P., and D. Wing,
                  "Session Traversal Utilities for NAT (STUN)",
                  RFC 5389, October 2008.

  [RFC5491]       Winterbottom, J., Thomson, M., and H. Tschofenig,
                  "GEOPRIV Presence Information Data Format Location
                  Object (PIDF-LO) Usage Clarification, Considerations,
                  and Recommendations", RFC 5491, March 2009.

  [TEREDO-SEL]    Ward, N., "Teredo Server Selection", Work
                  in Progress, July 2007.

  [TR069]         "TR-069, CPE WAN Management Protocol v1.1, Version:
                  Issue 1 Amendment 2", December 2007, <http://
                  www.broadband-forum.org/technical/download/
                  TR-069_Amendment-2.pdf>.

  [mDNS]          Cheshire, S. and M. Krochmal, "Multicast DNS", Work
                  in Progress, September 2009.
























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RFC 5687            GEOPRIV L7 LCP: Problem Statement         March 2010


Authors' Addresses

  Hannes Tschofenig
  Nokia Siemens Networks
  Linnoitustie 6
  Espoo  02600
  Finland

  Phone: +358 (50) 4871445
  EMail: [email protected]
  URI:   http://www.tschofenig.priv.at


  Henning Schulzrinne
  Columbia University
  Department of Computer Science
  450 Computer Science Building
  New York, NY  10027
  US

  Phone: +1 212 939 7004
  EMail: [email protected]
  URI:   http://www.cs.columbia.edu




























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