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Versions: (draft-tschofenig-geopriv-radius-lo) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 RFC 5580

Geopriv                                                    H. Tschofenig
Internet-Draft                                                   Siemens
Expires: January 17, 2006                                     F. Adrangi
                                                                   Intel
                                                                M. Jones
                                                                 A. Lior
                                                             Bridgewater
                                                           July 16, 2005


                  Carrying Location Objects in RADIUS
                  draft-ietf-geopriv-radius-lo-04.txt

Status of this Memo

   By submitting this Internet-Draft, each author represents that any
   applicable patent or other IPR claims of which he or she is aware
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   This Internet-Draft will expire on January 17, 2006.

Copyright Notice

   Copyright (C) The Internet Society (2005).

Abstract

   This document describes RADIUS attributes for conveying access
   network ownership and location information based on a civic and
   geospatial location format.




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   The distribution of location information is a privacy sensitive task.
   Dealing with mechanisms to preserve the user's privacy is important
   and addressed in this document.
















































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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  5
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  6
   3.  Delivery Methods for Location Information  . . . . . . . . . .  7
     3.1   Authentication/Authorization Phase Delivery  . . . . . . .  7
     3.2   Mid-session Authorization  . . . . . . . . . . . . . . . .  8
   4.  Scenarios  . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     4.1   Scenario 1 - Use of Location Information in AAA  . . . . . 10
     4.2   Scenario 2 - Use of Location Information for Other
           Services . . . . . . . . . . . . . . . . . . . . . . . . . 10
   5.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
     5.1   Operator-Namespace Attribute . . . . . . . . . . . . . . . 12
     5.2   Operator-Name Attribute  . . . . . . . . . . . . . . . . . 12
     5.3   Location-Information Attribute . . . . . . . . . . . . . . 13
       5.3.1   Civic Location Information . . . . . . . . . . . . . . 13
       5.3.2   Geospatial Location Information  . . . . . . . . . . . 15
   6.  Basic- and Extended-Policy-Rule Attributes . . . . . . . . . . 16
   7.  Location-Type Attribute  . . . . . . . . . . . . . . . . . . . 17
   8.  Capability Attribute . . . . . . . . . . . . . . . . . . . . . 18
   9.  Diameter RADIUS Interoperability . . . . . . . . . . . . . . . 20
   10.   Attributes . . . . . . . . . . . . . . . . . . . . . . . . . 21
     10.1  Operator-Namespace Attribute . . . . . . . . . . . . . . . 21
     10.2  Operator-Name Attribute  . . . . . . . . . . . . . . . . . 21
     10.3  Location-Information Attribute . . . . . . . . . . . . . . 22
     10.4  Basic Policy Rules Attribute . . . . . . . . . . . . . . . 26
     10.5  Extended Policy Rules Attribute  . . . . . . . . . . . . . 27
     10.6  Location-Type Attribute  . . . . . . . . . . . . . . . . . 28
     10.7  Capability Attribute . . . . . . . . . . . . . . . . . . . 28
   11.   Table of Attributes  . . . . . . . . . . . . . . . . . . . . 31
   12.   Matching with Geopriv Requirements . . . . . . . . . . . . . 32
     12.1  Distribution of Location Information at the User's
           Home Network . . . . . . . . . . . . . . . . . . . . . . . 32
     12.2  Distribution of Location Information at the Visited
           Network  . . . . . . . . . . . . . . . . . . . . . . . . . 33
     12.3  Requirements matching  . . . . . . . . . . . . . . . . . . 34
   13.   Example  . . . . . . . . . . . . . . . . . . . . . . . . . . 40
   14.   Privacy Considerations . . . . . . . . . . . . . . . . . . . 42
     14.1  Entity in the visited network  . . . . . . . . . . . . . . 42
     14.2  Entity in the home network . . . . . . . . . . . . . . . . 43
   15.   Security Considerations  . . . . . . . . . . . . . . . . . . 46
   16.   IANA Considerations  . . . . . . . . . . . . . . . . . . . . 49
     16.1  New Registry: Operator Type  . . . . . . . . . . . . . . . 49
     16.2  New Registry: Capabilities . . . . . . . . . . . . . . . . 49
   17.   Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . 51
   18.   References . . . . . . . . . . . . . . . . . . . . . . . . . 52
     18.1  Normative References . . . . . . . . . . . . . . . . . . . 52
     18.2  Informative References . . . . . . . . . . . . . . . . . . 52



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       Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 55
       Intellectual Property and Copyright Statements . . . . . . . . 56

















































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1.  Introduction

   Wireless LAN (WLAN) access networks are being deployed in public
   places such as airports, hotels, shopping malls, and coffee shops by
   a diverse set of operators such as cellular network operators (GSM
   and CDMA), Wireless Internet Service Providers (WISPs), and fixed
   broadband operators.

   When a user executes the network access authentication procedure to
   such a network, information about the location and ownership of this
   network needs to be conveyed to the user's home network to which the
   user has a contractual relationship.  The main intent of this
   document is to enable location aware billing (e.g., determine the
   appropriate tariff and taxation in dependence of the location of the
   access network/user), location aware subscriber authentication and
   authorization for roaming environments and to enable other location
   aware services.

   This document describes AAA attributes that are used by a AAA client
   or a local AAA server in an access network for conveying location-
   related information to the user's home AAA server.  This document
   defines attributes for RADIUS [1].

   Although the proposed attributes in this draft are intended for
   wireless LAN deployments, they can also be used in other types of
   wireless and wired networks whenever location information is
   required.

   Location information needs to be protected against unauthorized
   access and distribution to preserve the user's privacy with regard to
   location information. [11] defines requirements for a protocol-
   independent model for the access to geographic location information.
   The model includes a Location Generator (LG) that creates location
   information, a Location Server (LS) that authorizes access to
   location information, a Location Recipient (LR) that requests and
   receives information, and a Rule Maker (RM) that provides
   authorization policies to the LS which enforces access control
   policies on requests to location information.

   Althougth this document focuses on the use cases of location based
   authorization, charging, billing and taxation for network access
   RADIUS might also be used for location-based authorization for
   application layer services as well.  The extensions defined in this
   document are therefore not only applicable to a network access
   scenario.  A further description of these scenarios is outside the
   scope of this document.





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2.  Terminology

   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 [2].

   RADIUS specific terminology is borrowed from [1] and [3].

   Terminology related to privacy issues, location information and
   authorization policy rules is taken from [11].

   Based on today's protocols we assume that the location information is
   provided by the access network where the end host is attached.  As
   part of the network attachment, which includes the execution of an
   authentication and authorization protocol exchange, authentication is
   accomplished.  The authenticated identity can refer to a user, a
   device or something else.  Although there might often be a user
   associated with the authentication process (either directly or
   indirectly; indirectly when a binding between a device and a user
   exists) there is no assurance that a particular real-world entity
   (such as a person) triggered this process.  Since location based
   authorization is executed based on the network access authentication
   of a particular "user" it might be reasonable to talk about user's
   privacy within this document even though scenarios exist where this
   might not apply (and device or network privacy might be the correct
   term).  Furthermore, the authors believe that there is a relationship
   between the location of the network and the location of the entity
   that triggered the network access authentication.  Knowing the
   location of a network (where the user or end host is attached to)
   might in many networks also reveal the location of the user or end
   host.  In some networks it is even possible to provide a accurate
   location of the user or end host.  A similar assumption is also made
   with regard to the location information obtained via DHCP (see for
   example [4]).  This information might be used by applications in
   other protocols (such as SIP [12] with extensions [13]) to indicate
   the location of a particular user even though the location "only"
   refers to the location of the network or equipment within the
   network.  The assumption here is also that the location of the
   network has some relationship to the location of the end host (and
   subsequently to a user).  This assumption might not hold in all
   scenarios.  Nevertheless, it seems to be reasonable.

   Please note that the authors use the terms end host and user
   interchangably with respect to the used identities as part of the
   network access authentication.  The term 'user' is used whenever the
   privacy of the user could potentially be compromised.





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3.  Delivery Methods for Location Information

   Location Objects, which consist of location information and privacy
   rules, are transported over the RADIUS protocol from visited access
   network to the home AAA server.  To embed a Location Object into
   RADIUS a number of AVPs are used, such as Location-Information AVP,
   Basic-Policy-Rules AVP, Extended-Policy-Rules AVP, Location-Type AVP,
   Operator-Namespace AVP and Operator-Name AVP.  These AVPs can be
   delivered to the RADIUS server during the authentication/
   authorization phase described in Section 3.1, or in the mid-session
   using the dynamic authorization protocol framework described in
   Section 3.2.  This section describes messages flow for both delivery
   methods.

3.1  Authentication/Authorization Phase Delivery

   Figure 1 shows an example message flow for delivering location
   information during the network access authentication/authorization
   procedure.  Upon a network authentication request from an access
   network client, the NAS submits a RADIUS Access-Request message which
   contains location information attributes among other required
   attributes.  The attributes (including location information) are
   added based on some criteria, such as local policy and business
   relationship with subscriber's home network provider.  If no location
   information is attached although required by the aaa server an error
   message is returned.

   The authentication and/or authorization procedure is completed based
   on a number of criteria, including the newly defined Location-
   Information, Operator-Namespace, Operator-Name, Location-Type,
   Policy-Information attributes.  A RADIUS Accounting Request message
   may also carry location specific attributes.



















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    +---------+             +---------+                   +---------+
    | Network |             | Network |                   |   AAA   |
    | Access  |             | Access  |                   |  Server |
    | Client  |             | Server  |                   |         |
    +---------+             +---------+                   +---------+
        |                       |                              |
        | Authentication phase  |                              |
        | begin                 |                              |
        |---------------------->|                              |
        |                       |                              |
        |                       |                              |
        |                       | RADIUS                       |
        |                       | Access-Request               |
        |                       | + Location-Information       |
        |                       |   attributes                 |
        |                       |----------------------------->|
        |                       |                              |
        :                       :                              :
        :       Multiple Protocol Exchanges to perform         :
        :    Authentication, Key Exchange and Authorization    :
        :                  ...continued...                     :
        :                       :                              :
        |                       | RADIUS                       |
        |                       | Access-Accept                |
        |                       |  + Rule set Information      |
        |                       |<-----------------------------|
        | Authentication        |                              |
        | Accept                |                              |
        |<----------------------|                              |
        |                       |                              |
        |                       | RADIUS                       |
        |                       | Accounting Request           |
        |                       | + Location-Information       |
        |                       |   attributes                 |
        |                       |----------------------------->|
        |                       |                              |

    Figure 1: Message Flow: Authentication/Authorization Phase Delivery


3.2  Mid-session Authorization

   The mid-session delivery method uses the Change of Authorization
   (COA) message as defined in [5].  At anytime during the session the
   AAA server MAY send a COA message containing session identification
   attributes to the access network.  The COA message may instruct the
   access network to generate an Authorize-Only Access-Request (Access-
   Request with Service-Type set to "Authorize-Only") in which case the



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   NAS MUST include the location infromation in this Access-Request.

   Figure 2 shows the approach graphically.


    +---------+                                    +---------+
    |   AAA   |                                    |   AAA   |
    |  Client |                                    |  Server |
    |  (NAS)  |                                    |         |
    +---------+                                    +---------+
        |                                               |
        |  COA  + Service-Type "Authorize Only"         |
        |<----------------------------------------------|
        |                                               |
        |  COA NAK + Service-Type "Authorize Only"      |
        |          + Error-Cause  "Request Initiated"   |
        |---------------------------------------------->|
        |                                               |
        | Access-Request + Service-Type "Authorize Only"|
        |             + Location Information attributes |
        |             + Location Information policy     |
        |---------------------------------------------->|
        |                                               |
        | Access-Accept                                 |
        |<----------------------------------------------|
        |                                               |

             Figure 2: Message Flow: Mid-session Authorization

   Upon receiving the Authorize-Only message from the access network,
   the AAA server MUST respond with either an Access-Accept message or
   an Access-Reject message.



















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4.  Scenarios

   In the following subsections we describe two scenarios for use of
   location information.  The location information may refer to the
   (visited) network or to the user.  How the network obtains the user's
   location information is out of the scope of this document.  There are
   two consumers of location information: the AAA server and location-
   based services.  The privacy implications of these scenarios are
   described in Section 14.

4.1  Scenario 1 - Use of Location Information in AAA

   The home network operator requires location information for
   authorization and billing purposes.  The operator may deny service if
   location information is not available, or it may offer limited
   service.  The NAS delivers location information to the home AAA
   server.

   The user's location is transferred from the NAS to the RADIUS server.
   The NAS and intermediaries (if any) are not allowed to use that
   information other than to forward it to the home network.

   The RADIUS server authenticates and authorizes the user requesting
   access to the network.  If the user's location policies are available
   to the RADIUS server, the RADIUS server must deliver those policies
   in an Access Accept to the RADIUS client.  This information may be
   needed if intermediaries or other elements want to act as Location
   Servers (see Section 4.2).  If intermediaries do not receive these
   policies then they MUST NOT make any use of the location information
   other than forwarding it to the home network.

   Location Information may also be reported in accounting messages.
   Accounting messages are generated when the session starts, stops and
   periodically.  Accounting messages may also be generated when the
   user roams during handoff.  This information may be needed by the
   billing system to calculate the user's bill.  For example, there may
   be different rates applied based on the location and there may be
   different tax rates applied based on the location.  Unless otherwise
   specified by authorization rules, location information in the
   accounting stream MUST NOT be transmitted to third parties.

   The location information in the accounting stream MUST only be sent
   in the proxy chain to the home network (unless specified otherwise).

4.2  Scenario 2 - Use of Location Information for Other Services

   Location Servers are entities that receive the user's location
   information and transmit it to other entities.  In this second



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   scenario, Location Servers comprise also the NAS and the RADIUS
   server.  The RADIUS servers are in the home network, in the visited
   network, or in broker networks.

   Unless explicitly authorized by the user's location policy, location
   information MUST NOT be transmitted to other parties outside the
   proxy chain between the NAS and the Home RADIUS server.

   Upon authentication and authorization, the home RADIUS server must
   transmit the ruleset (if available) in an Access-Accept.  The RADIUS
   client, intermediate proxies are allowed to share location
   information if they received ruleset indicates that it is allowed.

   Note that the NAS is the source of all location information that is
   disseminated by RADIUS.  The NAS tags the location information with
   the policy rules or a reference to the policy rules received in an
   Access-Accept.  All location information in the accounting stream
   will also be tagged.

































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5.  Overview

   Location information and ownership of the access network is conveyed
   in the following RADIUS attributes: Operator-Namespace, Operator-
   Name, Location-Information and Location-Type.  Furthermore, the
   Basic-Policy-Rules and the Extended-Policy-Rules attributes are
   attached to the Location-Information attribute turning location
   information into a Location Object as defined in [11].

5.1  Operator-Namespace Attribute

   This attribute contains the description of an operator namespace
   which combined with the Operator-Name attribute serves to uniquely
   identify the owner of an access network.  The attribute value is a
   non-NULL terminated string whose Length MUST NOT exceed 253 bytes.
   This document defines three values for this attribute: GSM, CDMA, and
   REALM.  Additional namespaces require IANA registration and MUST be
   associated with an organization responsible for assigning and
   managing the operator namespace.

   The GSM operator namespace can be used to indicate operator names
   based on GSMA TADIG codes.  The TADIG Working Group within the GSM
   Association is the authority responsible for issuing unique Operator-
   Name values for operators of this type.

   The CDMA operator namespace can be used to indicate operator names
   based on the Home Network Identifier (HNI).  The HNI is the
   concatenation of the 3-digit Mobile Country Code (MCC) and 3-digit
   Mobile Network Code (MNC).  The IMSI Oversight Council (IOC) is the
   authority responsible for issuing unique Operator-Name values for
   operators of this type.

   The REALM operator namespace can be used to indicate operator names
   based on any registered domain name.  Such names are required to be
   unique and the rights to use a given realm name are obtained
   coincident with acquiring the rights to use a particular Fully
   Qualified Domain Name (FQDN).

5.2  Operator-Name Attribute

   This attribute contains an operator name which combined with the
   Operator-Namespace attribute serves to uniquely identifies the owner
   of an access network.  The attribute value is a non-NULL terminated
   string whose Length MUST NOT exceed 253 bytes.  The attribute value
   uniquely identifies the operator name within the scope of the
   operator type.





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5.3  Location-Information Attribute

   This document describes two formats for conveying location
   information: civic and geospatial location information.
   Section 5.3.1 defines the civic location information format.
   Section 5.3.2 defines the geospatial location information format.

   Additionally, the following fields provide more details about the
   transmitted location information.

   Entity: With the help of the 'Entity' field it is possible to
      differentiate whether the described Location Object refers to
      either the user's client device (as estimated by the network) or
      to the location of the AAA client (such as NAS).

   Method: The 'Method' field describes the method for obtaining
      location information.  GPS or manual configuration are possible
      methods for obtaining location information.  The inclusion of this
      field should help the user's home network to deduce further
      information about the accuracy and to provide an easier
      translation into a Location Object for transmission to third party
      entities (e.g., using SIP).  Note that the values for this field
      are taken from [14].


5.3.1  Civic Location Information

   Civic location is a popular way to describe the location of an
   entity.  Using an unstructured (as a text string) or a custom format
   for civic location format would limit automatic processing
   capabilities are limited.

   For this document, we take the civic location format defined in [4].

   The civic location format includes a number of fields, including the
   country (expressed as a two-letter ISO 3166 code) and the
   administrative units A1 through A6 of [4] .  This designation offers
   street-level precision.

   For completeness we include more detailed information from [4] with
   regard to the defined civic location elements:










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   +----------------------+----------------------+---------------------+
   | Label                | Description          | Example             |
   +----------------------+----------------------+---------------------+
   | country              | The country is       | US                  |
   |                      | identified by the    |                     |
   |                      | two-letter ISO 3166  |                     |
   |                      | code.                |                     |
   |                      |                      |                     |
   | A1                   | national             | New York            |
   |                      | subdivisions (state, |                     |
   |                      | region, province,    |                     |
   |                      | prefecture)          |                     |
   |                      |                      |                     |
   | A2                   | county, parish, gun  | King's County       |
   |                      | (JP), district (IN)  |                     |
   |                      |                      |                     |
   | A3                   | city, township, shi  | New York            |
   |                      | (JP)                 |                     |
   |                      |                      |                     |
   | A4                   | city division,       | Manhattan           |
   |                      | borough, city        |                     |
   |                      | district, ward, cho  |                     |
   |                      | (JP)                 |                     |
   |                      |                      |                     |
   | A5                   | neighborhood, block, | Morningside Heights |
   |                      | chome (JP)           |                     |
   |                      |                      |                     |
   | A6                   | street, banchi and   | Broadway            |
   |                      | gou (JP)             |                     |
   |                      |                      |                     |
   | AC                   | Additional code, JIS | 13203000003         |
   |                      | address code (JP)    |                     |
   |                      |                      |                     |
   | PRD                  | Leading street       | N, W                |
   |                      | direction            |                     |
   |                      |                      |                     |
   | POD                  | Trailing street      | SW                  |
   |                      | suffix               |                     |
   |                      |                      |                     |
   | STS                  | Street suffix        | Avenue, Street      |
   |                      |                      |                     |
   | HNO                  | House number,        | 123                 |
   |                      | numeric part only.   |                     |
   |                      |                      |                     |
   | HNS                  | House number suffix  | A, 1/2              |
   |                      |                      |                     |
   | LMK                  | Landmark or vanity   | Low Library         |
   |                      | address              |                     |



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   | LOC                  | Additional location  | Room 543            |
   |                      | information          |                     |
   |                      |                      |                     |
   | FLR                  | Floor                | 5                   |
   |                      |                      |                     |
   | NAM                  | Name (residence,     | Joe's Barbershop    |
   |                      | business or office   |                     |
   |                      | occupant)            |                     |
   |                      |                      |                     |
   | PC                   | Postal code          | 10027-0401          |
   +----------------------+----------------------+---------------------+

                                  Table 1

   More description of these civic location elements can be found in
   Section 3.4 of [4].  These elements can be used to express further
   information about the location, language specific settings via the
   'language' item and encoding information via the 'script' item.
   Section 13 shows usage examples of this attribute.

   All attributes are optional and can appear in any order.  The values
   are encoded using UTF-8 [6].

5.3.2  Geospatial Location Information

   This document reuses geospatial location information from [7] which
   defines latitude, longitude, and altitude, with resolution indicators
   for each.  The value in the Altitude field either indicates meters or
   floors (via the Altitude Type field).  As a coordinate reference
   system Section 2.1 of [7] defines (via extensible mechanism using
   IANA registration) three values in the 'Datum' field: WGS 84, NAD 83
   (with the associated vertical datum for the North American Vertical
   Datum of 1988), NAD 83 (with the associated vertical datum for the
   Mean Lower Low Water (MLLW).  WGS 84 is used by the GPS system.

   During a protocol run it is possible to return Location-Information
   attributes which provide both types of location information elements.
   If only one location information element is provided then civic
   location SHOULD be included in the request.












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6.  Basic- and Extended-Policy-Rule Attributes

   In some environments it is possible for the user to attach
   information about its privacy preferences.  These preferences allow
   the visited network, intermediate RADIUS proxies and the home network
   to authorize the distribution of the user's location information.

   Without the user providing authorization information two approaches
   are possible:

   o  The user hides its location information from the access network
      and from intermediate networks using the appropriate network
      access authentication mechanism.  Section 14 discusses these
      issues in more details.

   o  The access network attaches default authorization policies which
      indicates that intermediate networks and the home network should
      not distribute the location information to other entities.
      Additionally, the home network might have authorization policies
      which control distribution of location information.  Users can
      dynamically change their policies using the authroization
      framework defined in [15] and [16].

   With regard to authorization policies this document reuses work done
   in [14] and encodes it in an non-XML format.  Two fields ('sighting
   time' and 'time-to-live') are additionally included in the Location-
   Information attribute to conform to the Geopriv Requirements [11],
   Section 2.7.  Two RADIUS attributes are used for this purpose: Basic-
   Policy-Rule and Extended-Policy-Rule attribute.  The Basic-Policy-
   Rule attribute contains a fixed set of privacy relevant fields
   whereas the Extended-Policy-Rule attribute contains a reference to a
   more extensive authorization rule set.



















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7.  Location-Type Attribute

   This document uses the values defined in the location type registry
   [8].

   By using these location types it is possible to define more accurate
   location information.  Note that multiple values can be specified in
   this attribute.











































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8.  Capability Attribute

   The capability attribute allows the RADIUS client to indicate whether
   civic and/or geospatial location information can be provided to the
   RADIUS server.  This is useful to avoid sending location information
   with every request if no further out-of-band arrangements are made
   with regard to the transport of location information.  The AAA server
   uses the capability attribute to indicate that the AAA client has to
   provide civic and/or geospatial location information as part of this
   particular protocol exchange.  If the AAA server does not send a
   capability attribute then the AAA client MUST NOT return location
   information.  The user's authorization policies MUST be consulted by
   the AAA server before requesting location information delivery from
   the AAA client.  If the AAA server encounters that the AAA client
   does not support the desired location information it might respond
   with an Access-Reject with the corresponding error cause attribute
   (with the Location-Info-Required error code).

   Figure 3 shows a simple protocol exchange where the AAA client
   indicates that it is able to provide civic and geospatial location
   information and the AAA server indicates that that civic location
   information is desired for this particular exchange.





























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    +---------+                    +---------+
    |   AAA   |                    |   AAA   |
    |  Client |                    |  Server |
    |         |                    |         |
    +---------+                    +---------+
         |                              |
         |                              |
         | RADIUS                       |
         | Access-Request               |
         | + Capability                 |
         |   ('CIVIC_LOCATION',         |
         |    'GEO_LOCATION')           |
         |----------------------------->|
         |                              |
         | RADIUS                       |
         | Access-Challenge             |
         | + Capability                 |
         |   ('CIVIC_LOCATION')         |
         |<-----------------------------|
         |                              |
         | RADIUS                       |
         | Access-Request               |
         | + Location-Information       |
         |   (civic-location)           |
         |----------------------------->|
         |                              |
         |        ....                  |

                   Figure 3: Capability Exchange Example






















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9.  Diameter RADIUS Interoperability

   In deployments where RADIUS clients communicate with DIAMETER servers
   or DIAMETER clients communicate with RADIUS servers then a
   translation agent will be deployed and operate.  The NASREQ
   specification [17] provides translation services.  Furthermore, the
   RADIUS attributes specified in this document are also applicable for
   deployments where DIAMETER clients talk with DIAMETER servers.
   DIAMETER AVP Code numbers for corresponding RADIUS attributes are
   allocated as specified in DIAMETER Base Protocol specification
   Section 4.1 [9].








































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10.  Attributes

   This section defines the Operator-Namespace AVP, Operator-Name AVP,
   Location-Information AVP, Basic Policy Rules AVP, Extended Policy
   Rules AVP, Location-Type AVP and the Capability AVP.

10.1  Operator-Namespace Attribute

   Operator-Namespace Attribute SHOULD be sent in Access-Request, and
   Accounting-Request records where the Acc-Status-Type is set to Start,
   Interim, or Stop.

   A summary of the Operator-Namespace Attribute is shown below.

       0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Type          | Length        | Operator-Namespace           ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Type:
       To Be Assigned by IANA  - Operator-Namespace

     Length:
       >= 3 Bytes

     Operator-Namespace:
       The text field contains an Access Network Operator Type.
       Example: REALM


10.2  Operator-Name Attribute

   Operator-Name Attribute SHOULD be sent in Access-Request, and
   Accounting-Request records where the Acc-Status-Type is set to Start,
   Interim, or Stop.

   A summary of the Operator-Name Attribute is shown below.













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       0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Type          | Length        | Operator-Name                ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Type:
       To Be Assigned by IANA - Operator-Name

     Length:
       >= 3 Bytes

     Operator-Name:
       The text field contains an Access Network Operator Name.
       Example: anyisp.com


10.3  Location-Information Attribute

   Location-Information attribute SHOULD be sent in Access-Request, and
   Accounting-Request records where the Acc-Status-Type is set to Start,
   Interim or Stop if available.

   The Location-Information Attribute has two variations depending on
   civic or geospatial location information.  The format is shown below.


       0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   Type        |  Length       | Code          |  Entity       |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Sighting Time                                                 ~
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Sighting Time                                                 |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Time-to-Live                                                  ~
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Time-to-Live                                                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   Method      |    Location-Info                             ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+









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     Type (8 bits):
       To Be Assigned by IANA  - Location-Information

     Length (8 bits):
       >= 3 Bytes

     Code (8 bits):
       Describes the location format that is carried in this attribute:
       (0) describes civic location information
       (1) describes geospatial location information

     Entity (8 bits):
       Describes which location this attribute refers to:
       (0) describes the location of the user's client device
       (1) describes the location of the AAA client

     Sighting Time (64 bits):
       NTP timestamp for the 'sighting time' field.

     Time-to-Live (64 bits):
       NTP timestamp for the 'time-to-live' field.

     Method (8 bits):
       Describes the way that the location information was
       derived or discovered. The following values are defined:
       (0) Global Positioning System (GPS)
       (1) GPS with assistance (A-GPS)
       (2) Manual configured information
       (3) Provided by DHCP
       (4) Triangulation: triangulated from time-of-arrival,
           signal strength or similar measurements
       (5) Cell: location of the cellular radio antenna
       (6) IEEE 802.11 WLAN access point

     Location-Info (variable):
       Contains either civic or
       geospatial location information attributes.

   The following two fields need some explanation:

   sighting time: This field indicates when the Location Information was
      accurate.  The data type of this field is a string and the format
      is a 64 bit NTP timestamp [18].

   time-to-live: This field gives a hint until when location information
      should be considered current.  Note that the time-to-live field is
      different than retention-expires, which indicates the time the
      recipient is no longer permitted to possess the location



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      information and its encapsulating Location Object.  The data type
      of this field is a string and the format is a 64 bit NTP timestamp
      [18].

   For civic location information the Location-Info field in the above
   structure is defined as followed:


       0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |          Countrycode          |  Civic address elements      ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Countrycode (16 bits):
       Two-letter ISO 3166 country code in capital ASCII letters.

     Civic address elements (variable):
       The text field contains location information element.

   The format of the civic address elements is described in Section 3.3
   of [4] with a TLV pair (whereby the Type and Length fields are one
   octet long).  An example is given in Section 13.

   For geospatial location information the Location-Info field is
   defined as follows:

























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        0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   LaRes   |     Latitude                                      +
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Latitude      |    LoRes  |  Longitude                        +
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Longitude                 |  AT   |  AltRes   | Altitude  +
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                   Altitude                    |    Datum      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     LaRes (6 bits):
       Latitude resolution

     Latitude (34 bits)

     LoRes (6 bits):
       Longitude resolution.

     Longitude (34 bits)

     Altitude (30 bits)

     AltRes (6 bits):
       Altitude resolution

     AT (4 bits):
       Altitude Type for altitude. The following codes are defined:

       (1) Meters
       (2) Floors

    Datum (8 bits):
      Coordinate reference system
      The following codes for the this field are defined:

      (1) WGS 84
      (2) NAD 83 (with the associated vertical datum for
                  the North American Vertical Datum of 1988)
      (3) NAD 83 (with the associated vertical datum for
                  the Mean Lower Low Water (MLLW))

   The length of the Location-Information Attribute MUST NOT exceed 253
   octets.  The length of the geospatial location information format is
   fixed with 16 bytes plus a four byte header.

   The 'Datum' field contains an identifier for the coordinate system



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   used to interpret the values of Latitude, Longitude and Altitude.
   The field with value (2) and the value (3) both represent the NAD 83
   coordinate reference system but they differ from each other with
   regard to their vertical datum representation as briefly noted in
   Section 5.3.2 and described in more detail in [7].

10.4  Basic Policy Rules Attribute

   The Basic-Policy-Rules attribute MUST be sent in Access-Accept,
   Access-Challenge, Access-Request, Access-Reject and Accounting-
   Request messages if location information is transmitted with this
   exchange.  If authorization policy rules are available to the RADIUS
   client then the Access-Request MUST carry the Basic-Policy-Rules
   attribute to to the RADIUS server.

   A summary of the Basic-Policy-Rules attribute is shown below.

       0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Type          | Length        |R|  Flags                      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Retention Expires                                            ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Retention Expires                                             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Note Well                                                    ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Type :
       To Be Assigned by IANA  - Basic-Policy-Rules

     Length:
       > 3 Bytes

     Flag (16 bits):
       Only the first bit (R) is defined an corresponds to the
       retransmission-allowed field. All other bits are reserved.

     Retention Expires (64 bits):
       NTP timestamp for the 'retention-expires' field.

     Note Well (variable):
       This field contains a URI which points to
       human readable privacy instructions.

   This document reuses fields of the 'usage-rules' element, described
   in [14].  These fields have the following meaning:



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   retransmission-allowed: When the value of this element is '0', then
      the recipient of this Location Object is not permitted to share
      the enclosed location information, or the object as a whole, with
      other parties.  The value of '1' allows to share the location
      information with other parties by considering the extended policy
      rules.

   retention-expires: This field specifies an absolute date at which
      time the Recipient is no longer permitted to possess the location
      information.  The data type of this field is a string and the
      format is a 64 bit NTP timestamp [18].

   note-well: This field contains a URI which points to human readable
      privacy instructions.  This field is useful when location
      information is distributed to third party entities, which can
      include humans in a location based service.  RADIUS entities are
      not supposed to process this field.

      Whenever a Location Object leaves the AAA system the URI in the
      note-well attribute MUST be expanded to the human readable text.
      For example, when the Location Object is transferred to a SIP
      based environment then the human readable text is placed in the
      text is put into the 'note-well' attribute inside the 'usage-
      rules' element inside the PIDF-LO document (see [14]).


10.5  Extended Policy Rules Attribute

   The Extended-Policy-Rules attribute SHOULD be sent in Access-Accept,
   Access-Challenge, Access-and Access-Reject messages if location
   information is transmitted with this exchange.  If authorization
   policy rules are available to the RADIUS client then the Access-
   Request MUST carry the Basic-Policy-Rules attribute to to the RADIUS
   server.

   Ruleset reference field of this attribute is of variable length.  It
   contains a URI that indicates where a richer ruleset is available.
   The full ruleset SHOULD be fetched using Transport Layer Security
   (TLS).  As a deviation from [14] this field only contains a reference
   and does not carry an attached rule set.  This modification is
   motivated by the size limitations imposed by RADIUS.

   A summary of the Extended-Policy-Rules attribute is shown below.








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       0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Type          | Length        | Ruleset reference            ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Type :
       To Be Assigned by IANA  - Extended-Policy-Rules

     Length:
       > 3 Bytes

     Ruleset reference:
       The text field contains a URI which points to policy rules.


10.6  Location-Type Attribute

   Location-Type Attribute SHOULD be sent in Access-Request, and
   Accounting-Request records where the Acc-Status-Type is set to Start,
   Interim, or Stop if available.

   A summary of the Location-Type Attribute is shown below.

       0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Type          | Length        | Loc-Type                      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Type (8 bits):
       To Be Assigned by IANA - Location-Name

     Length (8 bits):
       4 Bytes

     Loc-Type (16 bits):
       The content of this field corresponds to the integer codes for
       access network location type.

   These integer codes for the location type can be found in Section 7.

10.7  Capability Attribute

   The Capability attribute SHOULD be sent in the Access-Request and the
   Access-Challenge messages.

   A summary of the Capability attribute is shown below.



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       0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Type          | Length        | Capabilities                ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Type:
       To Be Assigned by IANA - Operator-Name

     Length:
       >= 3 Bytes

     Capabilities (128 bits):
       This text field contains a numerical value that encodes the
       corresponding capabilities.
       Each value represents a bit position.

   Currently the following capabilities are specified:

   Capability Name:

      CIVIC_LOCATION


   Description:

      In the direction from the AAA client to the AAA server this
      capability refers to the ability to sent civic location
      information.  In the direction from the AAA server to the AAA
      client this capability refers to the desire of the AAA server to
      receive civic location.


   Numerical Value:

      A numerical value of this attribute is '0'.


   Capability Name:

      GEO_LOCATION


   Description:

      In the direction from the AAA client to the AAA server this
      capability refers to the ability to sent geospatial location
      information.  In the direction from the AAA server to the AAA



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      client this capability refers to the desire of the AAA server to
      receive geospatial location.


   Numerical Value:

      A numerical value of this attribute is '2'.












































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11.  Table of Attributes

   The following table provides a guide which attributes may be found in
   which RADIUS messages, and in what quantity.

   Request Accept Reject Challenge Accounting  #  Attribute
                                   Request
   0-1     0      0      0         0-1        TBD  Operator-Name
   0-1     0      0      0         0-1        TBD  Operator-Namespace
   0+      0      0      0         0+         TBD  Location-Information
   0-1     0-1    0-1    0-1       0-1        TBD  Basic-Policy-Rules
   0-1     0-1    0-1    0-1       0-1        TBD  Extended-Policy-Rules
   0-1     0      0      0         0-1        TBD  Location-Type
   0-1     0      0      0-1       0          TBD  Capability

   The Location-Information attribute may appear more than once.  This
   is useful if the size of one Location-Information attribute exceeds
   the maximum size of an AVP.  This might happen in case of civic
   location information that has a variable number of fields.  The
   individual fields used for representing civic location information
   inside the Location-Information AVP (see Section 5.3.1 MUST NOT
   appear more than once.  For example, it is not allowed to have a
   CAtype of 3 (indicating the name of the city) to appear more than
   once.

   The next table shows the occurrence of the error-cause attribute.

   Request Accept Reject Challenge Accounting #  Attribute
                                   Request
   0       0       0-1     0-1      0-1      TBD Location-Info-Required
   0       0       0-1     0        0        101 Error-Cause




















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12.  Matching with Geopriv Requirements

   This section compares the Geopriv requirements described in [11] and
   the approach of distributing Location Objects with RADIUS.

   The main usage scenario aimed for Location Object transport in RADIUS
   assumes that the Location Server and the Location Recipient are co-
   located at a single entity with regard to location based network
   access authorization, taxation and billing.  In Section 12.1 and
   Section 12.2 we discuss privacy implications when RADIUS is not used
   according to these usage scenario.

   In Section 12.3 Geopriv requirements are matched against these two
   scenarios.

12.1  Distribution of Location Information at the User's Home Network

   This section focuses on location information transport from the local
   AAA server (acting as the Location Generator) to the home AAA server
   (acting as the Location Server).  To use a more generic scenario we
   assume that the visited AAA and the home AAA server belong to
   different administrative domains.  The Location Recipient obtains
   location information about a particular Target via protocols
   specified outside the scope this document (e.g., SIP, HTTP or an
   API).

   Please note that the main usage scenario defined in this document
   assumes that the Location Server and the Location Recipient are co-
   located into a single entity with regard to location based network
   access authorization, taxation and billing.

   The subsequent figure shows the interacting entities graphically.



















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    visited network    |        home network
                       |
                       |        +----------+
                       |        |  Rule    |
                       |        | Holder   |
                       |        |          |
                       |        +----+-----+
                       |             |
                       |         rule|interface
                       |             V
     +----------+      |        +----------+               +----------+
     |Location  |  publication  | Location |  notification |Location  |
     |Generator |<------------->| Server   |<------------->|Recipient |
     |          |  interface    |          |  interface    |          |
     +----------+      |        +----------+               +----------+
                       |
     Local AAA      RADIUS       Home AAA     SIP/HTTP/API/etc.
     Server            |         Server
                       |

              Figure 16: Location Server at the Home Network

   The term 'Rule Holder' in Figure 16 denotes the entity which creates
   the authorization ruleset.

12.2  Distribution of Location Information at the Visited Network

   This section describes a scenario where Location Information is
   distributed by the visited network.

   In order for this scenario to be applicable the following two
   assumptions must hold:

   o  The visited network deploys a Location Server and wants to
      distribute Location Objects of a user

   o  The visited network is able to learn the user's identity

   The visited network provides location information to a Location
   Recipient (e.g., via SIP or HTTP).  During the network access
   authentication procedure the visited network is able to retrieve the
   user's authorization policies from the home AAA server.  This should
   ensure that the visited network acts according to the user's
   policies.

   The subsequent figure shows the interacting entities graphically.
   The transport of the Location Object is not shown in this figure
   since this aspect is already covered in the previous paragraph.



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    visited network    |        home network
                       |
     +----------+      |
     |Location  |      |
     |Recipient |      |
     |          |      |
     +----------+      |
          ^            |        +----------+
          |            |        |  Rule    |
          |            |        | Holder   |
      notification     |        |          |
       interface       |        +----+-----+
          |            |             |
          |            |         rule|interface
          v            |             V
     +----------+      |        +----------+
     |Location  | Rule Transport| Home AAA |
     |Generator |<------------->| Server   |
     |& Server  |   RADIUS      |          |
     +----------+      |        +----------+
                       |

             Figure 17: Location Server at the Visited Network


12.3  Requirements matching

   Section 7.1 of [11] details the requirements of a "Location Object".

   There are:


   Req. 1.  (Location Object generalities):

      *  Regarding requirement 1.1, the Location Object has to be
         understood by the RADIUS server (and possibly a Diameter server
         in case of interworking between the two) as defined in this
         document.  Due to the encoding of the Location Object it is
         possible to convert it to the format used in GMLv3 [19].  The
         same civic location information format is used in PIDF-LO [14]
         and this document.

      *  Regarding requirement 1.2, some fields of the Location Object
         defined in this document are optional.  See Section 5.3.1 as an
         example.

      *  Regarding requirement 1.3, the inclusion of the Location-Type
         attribute which gives a further classification of the location.



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         This attribute can be seen as an extension.

      *  Regarding requirement 1.4, the Location Object is extensible in
         the same fashion as RADIUS is extensible.

      *  Regarding requirement 1.5, the Location Object is useful for
         both receiving and sending location information as described in
         this document.

      *  Regarding requirement 1.6, the Location Object contains both
         location information and privacy rules.  Location information
         is described in Section 5.3 and the corresponding privacy rules
         are detailed in Section 10.4 and in Section 10.5.

      *  Regarding requirement 1.7, the Location Object is usable in a
         variety of protocols.  The format of the object is reused from
         other documents as detailed in the respective sections (see
         Section 5.3, Section 10.4 and in Section 10.5).

      *  Regarding requirement 1.8, the encoding of the Location Object
         has an emphasis on a lightweight encoding format.  As such it
         is useable on constrained devices.


   Req. 2.  (Location Object fields):

      *  Regarding requirement 2.1, the Target Identifier is carried
         within the network access authentication protocol (e.g., within
         the EAP-Identity Response when EAP is used and/or within the
         EAP method itself).  As described in Section 14 it has a number
         of advantages if this identifier is not carried in clear text.
         This is possible with certain EAP methods whereby the identity
         in the EAP-Identity Response only contains information relevant
         for routing the response to the user's home network.  The user
         identity is protected by the authentication and key exchange
         protocol.

      *  Regarding requirement 2.2, the Location Recipient is in the
         main scenario the home AAA server.  For a scenario where the
         Location Recipient is obtaining Location Information from the
         Location Server via HTTP or SIP the respective mechanisms
         defined in these protocols are used to identify the recipient.
         The Location Generator cannot, a priori, know the recipients if
         they are not defined in this protocol.

      *  Regarding requirement 2.3, the credentials of the Location
         Recipient are known to the RADIUS entities based on the
         security mechanisms defined in the RADIUS protocol itself.



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         Section 15 describes these security mechanisms offered by the
         RADIUS protocol.  The same is true for requirement 2.4.

      *  Regarding requirement 2.5, Section 5.3 describes the content of
         the Location Field.  Motion and direction vectors as listed in
         requirement 2.6 are not provided as attributes.  It is,
         however, possible to deduce the motion and direction of an
         entity via the Mid-session Delivery mechanism as shown in
         Figure 2.

      *  Regarding requirement 2.6, this document only describes one
         Location Data Type for civic and for geospatial location
         information, respectively.  No negotiation needs to take place.

      *  Regarding requirement 2.7, timing information is provided with
         'sighting time' and 'time-to-live' field defined in
         Section 10.4.

      *  Regarding requirement 2.8, a reference to an external (more
         detailed ruleset) is provided with the Section 10.5 attribute.

      *  Regarding requirement 2.9, security headers and trailers are
         provided as part of the RADIUS protocol or even as part of
         IPsec.

      *  Regarding requirement 2.10, a version number in RADIUS is
         provided with the IANA registration of the attributes.  New
         attributes are assigned a new IANA number.


   Req. 3.  (Location Data Types):

      *  Regarding requirement 3.1, this document defines two Location
         Data Types as described in Section 5.3.

      *  With the support of civic and geospatial location information
         support requirement 3.2 is fulfilled.

      *  Regarding requirement 3.3, the geospatial location information
         as defined in this document only refers to absolute
         coordinates.  However, the granularity of the location
         information can be reduced with the help of the AltRes, LoRes,
         LaRes fields described in the Location-Information attribute
         (see Section 10.3).

      *  Regarding requirement 3.4, further Location Data Types can be
         added via new coordinate reference systems (CRSs) (see Datum
         field in the Location-Information attribute of Section 5.3),



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         extensions to existing fields (e.g., new location types as
         shown in Section 7) or via additional attributes.

   Section 7.2 of [11] details the requirements of a "Using Protocol".
   These requirements are listed below:


   Req. 4.: The using protocol has to obey the privacy and security
      instructions coded in the Location Object and in the corresponding
      Rules regarding the transmission and storage of the LO.  This
      document requires, that RADIUS entities sending or receiving
      location MUST obey such instructions.


   Req. 5.: The using protocol will typically facilitate that the keys
      associated with the credentials are transported to the respective
      parties, that is, key establishment is the responsibility of the
      using protocol.  Section 15 specifies how security mechanisms are
      used in RADIUS and how they can be reused to provide security
      protection for the Location Object.  Additionally, the privacy
      considerations (see Section 14) are also relevant for this
      requirement.


   Req. 6.  (Single Message Transfer): In particular, for tracking of
      small target devices, the design should allow a single message/
      packet transmission of location as a complete transaction.  The
      encoding of the Location Object is specifically tailored towards
      the inclusion into a single message that even respects the (Path)
      MTU size.  The concept of a transaction is not immediately
      applicable to RADIUS.

   Section 7.3 of [11] details the requirements of a "Rule based
   Location Data Transfer".  These requirements are listed below:


   Req. 7.  (LS Rules): With the scenario shown in Figure 16 the
      decision of a Location Server to provide a Location Recipient
      access to location information is based on Rule Maker-defined
      Privacy Rules which are stored at the home network or are
      accessible for the home network.  With regard to the scenario
      shown in Figure 17 the Rule Maker-defined Privacy Rules are sent
      from the home network to the visited network as part of the
      Policy-Information attribute (see Section 10.4, Section 10.5 and
      Section 14 for more details).






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   Req. 8.  (LG Rules): For mid-session delivery it is possible to
      enforce the user's privacy rules for the transfer of the Location
      Object.  For the initial transmission of a Location Object the
      user would have to use network access authentication methods which
      provide user identity confidentiality which would render the
      Location Object completely useless for the visited network.  For
      the scenario shown in Figure 16 the visited network is already in
      possession of the users location information prior to the
      authentication and authorization of the user.  A correlation
      between the location and the user identity might, however, still
      not be possible for the visited network (as explained in
      Section 14).  The visited network MUST evaluate ruleset provided
      by the home AAA server as soon as possible.


   Req. 9.  (Viewer Rules): The Rule Maker might define (via mechanisms
      outside the scope of this document) which policy rules are
      disclosed to other entities.


   Req. 10.  (Full Rule language): Geopriv has defined a rule language
      capable of expressing a wide range of privacy rules which is
      applicable in the area of the distribution of Location Objects.  A
      basic ruleset is provided with the Basic-Policy-Rules attribute
      Section 10.4.  A reference to the extended ruleset is carried in
      Section 10.5.  The format of these rules are described in [15] and
      [16].


   Req. 11.  (Limited Rule language): A limited (or basic) ruleset is
      provided by the Policy-Information attribute Section 10.4 (and as
      introduced with PIDF-LO [14]).

   Section 7.4 of [11] details the requirements of a "Location Object
   Privacy and Security".  These requirements are listed below:


   Req. 12 (Identity Protection): Support for unlinkable pseudonyms is
      provided by the usage of a corresponding authentication and key
      exchange protocol.  Such protocols are available, for example,
      with the support of EAP as network access authentication methods.
      Some EAP methods support passive user identity confidentiality
      whereas others even support active user identity confidentiality.
      This issue is further discussed in Section 15.  The importance for
      user identity confidentiality and identity protection has already
      been recognized (see for example a document on 'EAP Method
      Requirements for Wireless LANs' [20]).




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   Req. 13.  (Credential Requirements): As described in Section 15
      RADIUS signaling messages can be protected with IPsec.  This
      allows a number of authentication and key exchange protocols to be
      used as part of IKE, IKEv2 or KINK.


   Req. 14.  (Security Features): Geopriv defines a few security
      requirements for the protection of Location Objects such as mutual
      end-point authentication, data object integrity, data object
      confidentiality and replay protection.  As described in Section 15
      these requirements are fulfilled with the usage of IPsec if the
      mutual authentication refers to the RADIUS entities (acting as
      various Geopriv entities) which directly communicate with each
      other.


   Req. 15.  (Minimal Crypto): A minimum of security mechanisms are
      mandated by the usage of RADIUS.  Communication security for
      Location Objects between AAA infrastructure elements is provided
      by the RADIUS protocol (including IPsec and its dynamic key
      management framework) rather than on relying on object security
      via S/SIME (which is not available with RADIUS).





























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13.  Example

   This section provides an example for a civic location information
   format within the Location-Information attribute.  The size of the
   geo-spatial location information object is fixed and well-described
   examples can be found in the Appendix of [7].

   Due to the size limitations of the RADIUS attributes we give a more
   detailed example borrowed from Section 4 of [4].


                +-------------+-----------+-------------------+
                | Type        | Length    | Value             |
                +-------------+-----------+-------------------+
                | Type        | 8 bits    | TBD               |
                | Length      | 8 bits    | --total length--  |
                | Code        | 16 bits   | 1                 |
                | Precision   | 8 bits    | 2                 |
                | Countrycode | 16 bits   | DE                |
                | CAtype      | 8 bits    | 1                 |
                | CAlength    | 8 bits    | 7                 |
                | CAvalue     | 7 bytes   | Bavaria           |
                | CAtype      | 8 bits    | 3                 |
                | CAlength    | 8 bits    | 6                 |
                | CAvalue     | 6 byte    | Munich            |
                | CAtype      | 8 bits    | 6                 |
                | CAlength    | 8 bits    | 11                |
                | CAvalue     | 11 bytes  | Marienplatz       |
                | CAtype      | 8 bits    | 19                |
                | CAlength    | 8 bits    | 1                 |
                | CAvalue     | 1 byte    | 8                 |
                | CAtype      | 8 bits    | 24                |
                | CAlength    | 8 bits    | 5                 |
                | CAvalue     | 5 bytes   | 80331             |
                +-------------+-----------+-------------------+

   The Length element provides the length of the entire payload minus
   the length of the initial 'Type', the 'Length' and the 'Code'
   attribute.  The 'Entity' field has a value of '2' which refers to the
   location of the user's client.  The 'CountryCode' field is set to
   'DE'.  Note that the subsequent attributes are in Type-Length-Value
   format.  Type '1' indicates the region of 'Bavaria', '3' refers to
   the city 'Munich', '6' to the street 'Marienplatz', the house number
   '8' is indicated by the type '19' and the zip code of '80331' is of
   type '24'.

   The length of the elements need to consider the fact that all CAvalue
   elements are UTF-8 encoded.



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   The following example illustrates a civic address in Japan.

                +-------------+-----------+-------------------+
                | Type        | Length    | Value             |
                +-------------+-----------+-------------------+
                | Type        | 8 bits    | TBD               |
                | Length      | 8 bits    | --total length--  |
                | Code        | 16 bits   | 1                 |
                | Precision   | 8 bits    | 2                 |
                | Countrycode | 16 bits   | JP                |
                | CAtype      | 8 bits    | 1                 |
                | CAlength    | 8 bits    | 5                 |
                | CAvalue     | 7 bytes   | Tokyo             |
                | CAtype      | 8 bits    | 3                 |
                | CAlength    | 8 bits    | 13                |
                | CAvalue     | 6 byte    | Musashino-shi     |
                | CAtype      | 8 bits    | 5                 |
                | CAlength    | 8 bits    | 7                 |
                | CAvalue     | 11 bytes  | 3-chome           |
                | CAtype      | 8 bits    | 30                |
                | CAlength    | 8 bits    | 8                 |
                | CAvalue     | 1 byte    | 180-8585          |
                | CAtype      | 8 bits    | 32                |
                | CAlength    | 8 bits    | 11                |
                | CAvalue     | 5 bytes   | 13203000003       |
                +-------------+-----------+-------------------+

   Please note that the CAtype 32 ("additional code" item) provides an
   additional, country-specific code identifying the location, such as
   the Japan Industry Standard (JIS) address code.





















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14.  Privacy Considerations

   This section discusses privacy implications for the distribution of
   location information within RADIUS.

   In many cases the location information of the network also reveals
   the current location of the user with a certain degree of precision
   depending on the mechanism used, the positioning system, update
   frequency, where the location was generated, size of the network and
   other mechanisms (such as movement traces or interpolation).

   Two entities might act as Location Servers as shown in Section 4, in
   Figure 16 and in Figure 17:

14.1  Entity in the visited network

   In this scenario it is difficult to obtain authorization policies
   from the end host (or user) immediately when the user attaches to the
   network.  In this case we have to assume that the visited network
   does not allow unrestricted distribution of location information to
   other than the intended recipients (e.g., to third party entities).

   The visited network MUST behave according to the following
   guidelines:

   o  Per default only the home network is allowed to receive location
      information.  The visited network MUST NOT distribute location
      information to third parties without seeing the user's privacy
      rule se.

   o  If the home network provides the Basic-Policy-Rules attribute
      either as part of the Access-Accept, the Access-Reject or the
      Access-Challenge message then the visited network MUST follow the
      guidance given with these rules.

   o  If the home network provides the Extended-Policy-Rules attributes
      either as part of the Access-Accept, the Access-Reject or the
      Access-Challenge message then the visited network MUST fetch the
      full ruleset at the indicated URL and MUST follow the guidance
      given with these rules.

   o  If the RADIUS client in the visited network learns the basic rule
      set or a reference to the extended rule set by means outside the
      RADIUS protocol (e.g., provided by the end host) then it MUST
      include the Basic-Policy-Rules and the Extended-Policy-Rules
      attribute in the Access-Request message towards the home AAA
      server.  Furthermore, the visited network MUST evaluate these
      rules prior to the transmission of location information either to



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      the home network or a third party.  The visited network MUST
      follow the guidance given with these rules.

   o  If the RADIUS client in the visited network receives the Basic-
      Policy-Rules attribute with Access-Accept or the Access-Challenge
      message then the Basic-Policy-Rules MUST be attach in subsequent
      RADIUS messages which contain the Location-Information attribute
      (such as interim accounting messages).

   o  If the RADIUS client in the visited network receives the Extended-
      Policy-Rules attribute with Access-Accept or the Access-Challenge
      message then the Basic-Policy-Rules attribute MUST be attach in
      subsequent RADIUS messages which contain the Location-Information
      attribute (such as interim accounting messages).


14.2  Entity in the home network

   The AAA server in the home network might be an ideal place for
   storing authorization policies.  The user typically has a contractual
   relationship with his home network and hence the trust relationship
   between them is stronger.  Once the infrastructure is deployed and
   useful applications are available there might be a strong desire to
   use location information for other purposes as well (such as location
   aware applications).  Authorization policy rules described in [16]
   and in [15] are tailored for this environment.  These policies might
   be useful for limiting further distribution of the user's location to
   other location based services.  The home AAA server (or a similar
   entity) thereby acts as a location server for access to location
   services.

   The home network MUST behave according to the following guidelines:

   o  As a default policy the home network MUST NOT distribute the
      user's location information to third party entities.

   o  If a user provides basic authorization policies then these rules
      MUST be returned to the visited network in the Access-Accept, the
      Access-Reject or the Access-Challenge message.

   o  If a user provides basic authorization policies then these rules
      MUST be returned to the visited network in the Access-Accept, the
      Access-Reject or the Access-Challenge message.

   o  If a user provides extended authorization policies then they MUST
      be accessible for the visited networking using a reference to
      these rule set.  The Extended-Policy-Rules attribute MUST include
      the reference and they MUST be sent to the visited network in the



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      Access-Accept, the Access-Reject or the Access-Challenge message.

   o  The home network MUST follow the user provided rule set for both
      local storage and for further distribution.  With regard to the
      usage of these rules the home network MUST ensure that the users
      preferences are taken care of within the given boundaries (such as
      legal regulations or operational considerations).  For example, a
      user might not want the home network to store information about
      its location information beyond a indicated time frame.  However,
      a user might on the other hand want to ensure that disputes
      concerning the billed amount can be resolved. location information
      might help to resolve the dispute.  The user might, for example,
      be able to show that he has never been at the indicated place.

   o  If the policy rules provided by the user indicate that location
      information must not be distributed at all then the home network
      MUST provide the Basic-Policy-Rules to the RADIUS entity in the
      visited network via an Access-Accept, the Access-Reject and the
      Access-Challenge message.  The RADIUS server in the user's home
      network would set the 'Retention-Expires' and the 'Retransmission-
      allowed' field to the user indicated value.

   For the envisioned usage scenarios, the identity of the user and his
   device is tightly coupled to the transfer of location information.
   If the identity can be determined by the visited network or AAA
   brokers, then it is possible to correlate location information with a
   particular user.  As such, it allows the visited network and brokers
   to learn movement patterns of users.

   The identity of the user can "leak" to the visited network or AAA
   brokers in a number of ways:

   o  The user's device may employ a fixed MAC address, or base its IP
      address on such an address.  This enables the correlation of the
      particular device to its different locations.  Techniques exist to
      avoid the use of an IP address that is based on MAC address [21].
      Some link layers make it possible to avoid MAC addresses or change
      them dynamically.

   o  Network access authentication procedures such as PPP CHAP [22] or
      EAP [23] may reveal the user's identity as a part of the
      authentication procedure.  Techniques exist to avoid this problem
      in EAP, for instance by employing private Network Access
      Identifiers (NAIs) in the EAP Identity Response message [24] and
      by method-specific private identity exchange in the EAP method
      (e.g., [25], [26], [27]).  Support for identity privacy within
      CHAP is not available.




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   o  AAA protocols may return information from the home network to the
      visited in a manner that makes it possible to either identify the
      user or at least correlate his session with other sessions, such
      as the use of static data in a Class attribute [1] or in some
      accounting attribute usage scenarios [28].

   o  Mobility mechanisms may reveal some permanent identifier (such as
      a home address) in cleartext in the packets relating to mobility
      signaling.

   o  Application protocols may reveal other permanent identifiers.

   Note that to prevent the correlation of identities with location
   information it is necessary to prevent leakage of identity
   information from all sources, not just one.

   Unfortunately, most users are not educated about the importance of
   identity confidentiality and there is a lack of support for it in
   many protocols.  This problem is made worse by the fact that the
   users may be unable to choose particular protocols, as the choice is
   often dictated by the type of network they wish to access, the kind
   of equipment they have, or the type of authentication method they are
   using.

   A scenario where the user is attached to the home network is, from a
   privacy point of view, simpler than a scenario where a user roams
   into a visited network since the NAS and the home AAA are in the same
   administrative domain.  No direct relationship between the visited
   and the home network operator may be available and some AAA brokers
   need to be consulted.  With subscription-based network access as used
   today the user has a contractual relationship with the home network
   provider which could allow higher privacy considerations to be
   applied (including policy rules stored at the home network itself for
   the purpose of restricting further distribution).

   In many cases it is necessary to secure the transport of location
   information along the RADIUS infrastructure.  Mechanisms to achieve
   this functionality are discussed in Section 15.













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15.  Security Considerations

   Requirements for the protection of a Location Object are defined in
   [11]: Mutual end-point authentication, data object integrity, data
   object confidentiality and replay protection.  The distribution of
   location information can be restricted with the help of authorization
   policies.  Basic authorization policies are attached to the location
   information itself, in the same fashion as described in [14].  It is
   possible that the user was already able to transfer some
   authorization policies to the access network to restrict the
   distribution of location information.  This is, however, rather
   unlikely in case of roaming users.  Hence, it will be primarily the
   NAS creating the Location Object which also sets the authorization
   policies.  If no authorization information is provided by the user
   then the visited network MUST set the authorization policies to only
   allow the home AAA server to use the provided location information.
   Other entities, such as the visited network and possibly AAA brokers
   MUST NOT use the location information for a purpose other than
   described in this document.  More extensible authorization policies
   can be stored at the user's home network.  These policies are useful
   when location information is distributed to other entities in a
   location-based service.  This scenario is, however, outside the scope
   of this document.

   It is necessary to use authorization policies to limit the
   unauthorized distribution of location information.  The security
   requirements which are created based on [11] are inline with threats
   which appear in the relationship with disclosure of location
   information as described in [29].  PIDF-LO [14] proposes S/MIME to
   protect the Location Object against modifications.  S/SIME relies on
   public key cryptography which raises performance, deployment and size
   considerations.  Encryption would require that the local AAA server
   or the NAS knows the recipient's public key (e.g., the public key of
   the home AAA server).  Knowing the final recipient of the location
   information is in many cases difficult for RADIUS entities.  Some
   sort of public key infrastructure would be required to obtain the
   public key and to verify the digital signature (at the home network).
   Providing per-object cryptographic protection is, both at the home
   and at the visited network, computationally expensive.

   If no authentication, integrity and replay protection between the
   participating RADIUS entities is provided then an adversaries can
   spoof and modify transmitted AVPs.  Two security mechanisms are
   proposed for RADIUS:

   o  [1] proposes the usage of a static key which might raise some
      concerns about the lack dynamic key management.




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   o  RADIUS over IPsec [30] allows to run standard key management
      mechanisms, such as KINK [31], IKE and IKEv2 [32], to establish
      IPsec security associations.  Confidentiality protection MUST be
      used to prevent eavesdropper gaining access to location
      information.  Confidentiality protection is not only a property
      required by this document, it is also required for the transport
      of keying material in the context of EAP authentication and
      authorization.  Hence, this requirement is, in many environments,
      already fulfilled.  Mutual authentication must be provided between
      the local AAA server and the home AAA server to prevent man-in-
      the-middle attacks from being successful.  This is another
      requirement raised in the area of key transport with RADIUS and
      does not represent a deployment obstacle.  The performance
      advantages superior compared to the usage of S/MIME and object
      security since the expensive authentication and key exchange
      protocol run needs to be provided only once (for a long time).
      Symmetric channel security with IPsec is highly efficient.  Since
      IPsec protection is suggested as a mechanism to protect RAIDUS
      already no additional considerations need to be addressed beyond
      those described in [30].  Where an untrusted AAA intermediary is
      present, the Location Object MUST NOT be provided to the
      intermediary.

   In case that IPsec protection is not available for some reason and
   RADIUS specific security mechanisms have to be used then the
   following considerations apply.  The Access-Request message is not
   integrity protected.  This would allow an adversary to change the
   contents of the Location Object or to insert and modify attributes
   and fields or to delete attributes.  To address these problems the
   Message-Authenticator (80) can be used to integrity protect the
   entire Access-Request packet.  The Message-Authenticator (80) is also
   required when EAP is used and hence is supported by many modern
   RADIUS servers.

   Access-Request packets including Location attribute(s) without a
   Message-Authenticator(80) attribute SHOULD be silently discarded by
   the RADIUS server.  A RADIUS server supporting the Location
   attributes MUST calculate the correct value of the Message-
   Authenticator(80) and MUST silently discard the packet if it does not
   match the value sent.

   Access-Accept, including Location attribute(s) without a Message-
   Authenticator(80) attribute SHOULD be silently discarded by the NAS.
   A NAS supporting the Location attribute MUST calculate the correct
   value of a received Message-Authenticator(80) and MUST silently
   discard the packet if it does not match the value sent.

   RADIUS and DIAMETER make some assumptions about the trust between



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   traversed AAA entities in sense that object level security is not
   provided by neither RADIUS nor DIAMETER.  Hence, some trust has to be
   placed on the AAA entities to behave according to the defined rules.
   Furthermore, the AAA protocols do not involve the user in their
   protocol interaction except for tunneling authentication information
   (such as EAP messages) through their infrastructure.  RADIUS and
   DIAMETER have even become a de-facto protocol for key distribution.
   Hence, in the past there were some concerns about the trust placed
   into the infrastructure particularly from the security area when it
   comes to keying.  The EAP keying infrastructure is described in [33].









































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16.  IANA Considerations

   The authors request that the Attribute Types, and Attribute Values
   defined in this document be registered by the Internet Assigned
   Numbers Authority (IANA) from the RADIUS name spaces as described in
   the "IANA Considerations" section of RFC 2865 [1], in accordance with
   BCP 26 [10].  Additionally, the Attribute Type should be registered
   in the Diameter name space.

   This document defines the following AVPs:

         Operator-Name
         Operator-Namespace
         Location-Information
         Basic-Policy-Rules
         Extended-Policy-Rules
         Location-Name
         Capability

   Please refer to Section 11 for the registered list of numbers.

   This document also instructs IANA to assign a new value for the
   Error-Cause attribute [5], of "Location-Info-Required" TBA.

   Additionally, IANA is requested to create the following new
   registries:

16.1  New Registry: Operator Type

   This document also defines a registry for the Operator-Namespace
   attribute.  Initially, IANA is requested to register the following
   values and associated registry owners for the operator namespace:

          +--------------------+----------------------------+
          | Operator-Namespace | Registry Owner             |
          +--------------------+----------------------------+
          | GSM                | GSM Association: TADIG WG  |
          | CDMA               | IMSI Oversight Council     |
          | REALM              | IANA or delegate           |
          +--------------------+----------------------------+

   Following the policies outline in [10] new Operator-Namespaces will
   be assigned after Expert Review by the Geopriv working group or its
   designated successor.

16.2  New Registry: Capabilities

   This document creates a new IANA registry for capabilities.



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   Currently two capabilities are defined as shown in Section 10.7

   Following the policies outline in RFC 2434 [10], these tokens are
   assigned on a 'First Come First Served' policy.  Each registration
   must include the name of the capability, a brief description and a
   numerical value respresenting a bit in the capability bit-string:

   Capability Name:

      Identifier of the capability


   Description:

      Brief description indicating the meaning of the capability.


   Numerical Value:

      A numerical value that is placed into the Capability attribute.































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17.  Acknowledgments

   The authors would like to thank the following people for their help
   with a previous version of this draft and for their input:

      Chuck Black

      Paul Congdon

      Jouni Korhonen

      Sami Ala-luukko

      Farooq Bari

      Ed Van Horne

      Mark Grayson

      Jukka Tuomi

      Jorge Cuellar

      Christian Guenther

   Henning Schulzrinne provided the civic location information content
   found in this draft.  The geospatial location information format is
   based on work done by J. Polk, J. Schnizlein and M. Linsner.  The
   authorization policy format is based on the work done by Jon
   Peterson.

   The authors would like to thank Victor Lortz, Jose Puthenkulam,
   Bernrad Aboba, Jari Arkko, Parviz Yegani, Serge Manning, Kuntal
   Chowdury, Pasi Eronen, Blair Bullock and Eugene Chang for their
   feedback to an initial version of this draft.  We would like to thank
   Jari Arkko for his text contributions.  Lionel Morand provided
   detailed feedback on numerous issues.  His comments helped to improve
   the quality of this document.  Jouni Korhonen and John Loughney
   helped us with the Diameter RADIUS interoperability.  Finally,
   Andreas Pashalidis reviewed the final document and provided a number
   of comments.

   This document is based on the discussions within the IETF GEOPRIV
   working group.  Therefore, the authors thank Henning Schulzrinne,
   James Polk, John Morris, Allison Mankin, Randall Gellens, Andrew
   Newton, Ted Hardie, Jon Peterson for their time to discuss a number
   of issues with us.  We thank Stephen Hayes for aligning this work
   with 3GPP activities.



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18.  References

18.1  Normative References

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

   [2]   Bradner, S., "Key words for use in RFCs to Indicate Requirement
         Levels", March 1997.

   [3]   Rigney, C., "RADIUS Accounting", RFC 2866, June 2000.

   [4]   Schulzrinne, H., "Dynamic Host Configuration Protocol (DHCPv4
         and DHCPv6) Option for Civic  Addresses Configuration
         Information", draft-ietf-geopriv-dhcp-civil-06 (work in
         progress), May 2005.

   [5]   Chiba, M., Dommety, G., Eklund, M., Mitton, D., and B. Aboba,
         "Dynamic Authorization Extensions to Remote Authentication Dial
         In User Service (RADIUS)", RFC 3576, July 2003.

   [6]   Yergeau, F., "UTF-8, a transformation format of ISO 10646",
         STD 63, RFC 3629, November 2003.

   [7]   Polk, J., Schnizlein, J., and M. Linsner, "Dynamic Host
         Configuration Protocol Option for Coordinate-based Location
         Configuration Information", RFC 3825, July 2004.

   [8]   Schulzrinne, H. and H. Tschofenig, "Location Types Registry",
         draft-ietf-geopriv-location-types-registry-01 (work in
         progress), July 2005.

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

   [10]  Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
         Considerations Section in RFCs", BCP 26, RFC 2434,
         October 1998.

18.2  Informative References

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

   [12]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A.,
         Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP:
         Session Initiation Protocol", RFC 3261, June 2002.



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   [13]  Polk, J. and B. Rosen, "Session Initiation Protocol Location
         Conveyance", draft-ietf-sip-location-conveyance-00 (work in
         progress), June 2005.

   [14]  Peterson, J., "A Presence-based GEOPRIV Location Object
         Format", draft-ietf-geopriv-pidf-lo-03 (work in progress),
         September 2004.

   [15]  Schulzrinne, H., "A Document Format for Expressing Privacy
         Preferences", draft-ietf-geopriv-common-policy-04 (work in
         progress), February 2005.

   [16]  Schulzrinne, H., "A Document Format for Expressing Privacy
         Preferences for Location  Information",
         draft-ietf-geopriv-policy-05 (work in progress), November 2004.

   [17]  Calhoun, P., Zorn, G., Spence, D., and D. Mitton, "Diameter
         Network Access Server Application",
         draft-ietf-aaa-diameter-nasreq-17 (work in progress),
         July 2004.

   [18]  Mills, D., "Network Time Protocol (Version 3) Specification,
         Implementation", RFC 1305, March 1992.

   [19]  "Open Geography Markup Language (GML) Implementation
         Specification", OGC 02-023r4,
         http://www.opengis.org/techno/implementation.htm",  ,
         January 2003.

   [20]  Stanley, D., Walker, J., and B. Aboba, "Extensible
         Authentication Protocol (EAP) Method Requirements for Wireless
         LANs", RFC 4017, March 2005.

   [21]  Narten, T. and R. Draves, "Privacy Extensions for Stateless
         Address Autoconfiguration in IPv6", RFC 3041, January 2001.

   [22]  Simpson, W., "PPP Challenge Handshake Authentication Protocol
         (CHAP)", RFC 1994, August 1996.

   [23]  Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H.
         Levkowetz, "Extensible Authentication Protocol (EAP)",
         RFC 3748, June 2004.

   [24]  Aboba, B., "The Network Access Identifier",
         draft-ietf-radext-rfc2486bis-05 (work in progress),
         February 2005.

   [25]  Arkko, J. and H. Haverinen, "Extensible Authentication Protocol



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         Method for 3rd Generation Authentication  and Key Agreement
         (EAP-AKA)", draft-arkko-pppext-eap-aka-15 (work in progress),
         December 2004.

   [26]  Josefsson, S., Palekar, A., Simon, D., and G. Zorn, "Protected
         EAP Protocol (PEAP) Version 2",
         draft-josefsson-pppext-eap-tls-eap-10 (work in progress),
         October 2004.

   [27]  Tschofenig, H., "EAP IKEv2 Method (EAP-IKEv2)",
         draft-tschofenig-eap-ikev2-06 (work in progress), May 2005.

   [28]  Adrangi, F., "Chargeable User Identity",
         draft-ietf-radext-chargeable-user-id-05 (work in progress),
         May 2005.

   [29]  Danley, M., "Threat Analysis of the Geopriv Protocol",
         RFC 3694, September 2003.

   [30]  Aboba, B. and P. Calhoun, "RADIUS (Remote Authentication Dial
         In User Service) Support For Extensible Authentication Protocol
         (EAP)", RFC 3579, September 2003.

   [31]  Sakane, S., "Kerberized Internet Negotiation of Keys (KINK)",
         draft-ietf-kink-kink-08 (work in progress), July 2005.

   [32]  Kaufman, C., "Internet Key Exchange (IKEv2) Protocol",
         draft-ietf-ipsec-ikev2-17 (work in progress), October 2004.

   [33]  Aboba, B., "Extensible Authentication Protocol (EAP) Key
         Management Framework", draft-ietf-eap-keying-06 (work in
         progress), April 2005.

   [34]  Schulzrinne, H., "RPID: Rich Presence Extensions to the
         Presence Information Data Format  (PIDF)",
         draft-ietf-simple-rpid-07 (work in progress), June 2005.

   [35]  Adrangi, F., "Access Network Bandwidth Capability",
         draft-adrangi-radius-bandwidth-capability-01 (work in
         progress), July 2004.

   [36]  Aboba, B., "The Network Access Identifier",
         draft-arkko-roamops-rfc2486bis-02 (work in progress),
         July 2004.







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Authors' Addresses

   Hannes Tschofenig
   Siemens
   Otto-Hahn-Ring 6
   Munich, Bavaria  81739
   Germany

   Email: Hannes.Tschofenig@siemens.com


   F. Adrangi
   Intel Corporatation
   2111 N.E. 25th Avenue
   Hillsboro OR
   USA

   Email: farid.adrangi@intel.com


   Mark Jones
   Bridgewater Systems Corporation
   303 Terry Fox Drive
   Ottawa, Ontario  K2K 3J1
   CANADA

   Email: mark.jones@bridgewatersystems.com


   Avi Lior
   Bridgewater Systems Corporation
   303 Terry Fox Drive
   Ottawa, Ontario  K2K 3J1
   CANADA

   Email: avi@bridgewatersystems.com















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