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RFC 5580

Proposed STD
Pages: 53
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Carrying Location Objects in RADIUS and Diameter

Part 1 of 2, p. 1 to 28
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Network Working Group                                 H. Tschofenig, Ed.
Request for Comments: 5580                        Nokia Siemens Networks
Category: Standards Track                                     F. Adrangi
                                                                   Intel
                                                                M. Jones
                                                                 A. Lior
                                                             Bridgewater
                                                                B. Aboba
                                                   Microsoft Corporation
                                                             August 2009


            Carrying Location Objects in RADIUS and Diameter

Abstract

   This document describes procedures for conveying access-network
   ownership and location information based on civic and geospatial
   location formats in Remote Authentication Dial-In User Service
   (RADIUS) and Diameter.

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

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (c) 2009 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents in effect on the date of
   publication of this document (http://trustee.ietf.org/license-info).
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.

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Table of Contents

   1. Introduction ....................................................3
   2. Terminology .....................................................3
   3. Delivery Methods for Location Information .......................3
      3.1. Location Delivery Based on Out-of-Band Agreements ..........4
      3.2. Location Delivery Based on Initial Request .................5
      3.3. Location Delivery Based on Mid-Session Request .............6
      3.4. Location Delivery in Accounting Messages ..................10
   4. Attributes .....................................................11
      4.1. Operator-Name Attribute ...................................12
      4.2. Location-Information Attribute ............................14
      4.3. Location-Data Attribute ...................................16
           4.3.1. Civic Location Profile .............................17
           4.3.2. Geospatial Location Profile ........................17
      4.4. Basic-Location-Policy-Rules Attribute .....................18
      4.5. Extended-Location-Policy-Rules Attribute ..................20
      4.6. Location-Capable Attribute ................................21
      4.7. Requested-Location-Info Attribute .........................23
   5. Table of Attributes ............................................28
   6. Diameter RADIUS Interoperability ...............................30
   7. Security Considerations ........................................31
      7.1. Communication Security ....................................31
      7.2. Privacy Considerations ....................................32
           7.2.1. RADIUS Client ......................................33
           7.2.2. RADIUS Server ......................................34
           7.2.3. RADIUS Proxy .......................................34
      7.3. Identity Information and Location Information .............34
   8. IANA Considerations ............................................36
      8.1. New Registry: Operator Namespace Identifier ...............36
      8.2. New Registry: Location Profiles ...........................37
      8.3. New Registry: Location-Capable Attribute ..................38
      8.4. New Registry: Entity Types ................................39
      8.5. New Registry: Privacy Flags ...............................39
      8.6. New Registry: Requested-Location-Info Attribute ...........39
   9. Acknowledgments ................................................40
   10. References ....................................................42
      10.1. Normative References .....................................42
      10.2. Informative References ...................................42
   Appendix A.  Matching with GEOPRIV Requirements ...................45
     A.1.  Distribution of Location Information at the User's
           Home Network ..............................................45
     A.2.  Distribution of Location Information at the Visited
           Network ...................................................46
     A.3.  Requirements Matching .....................................47

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1.  Introduction

   This document defines attributes within RADIUS and Diameter that can
   be used to convey location-related information within authentication
   and accounting exchanges.

   Location information may be useful in a number of scenarios.
   Wireless networks (including wireless LAN) 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, Wireless Internet Service Providers (WISPs), and fixed
   broadband operators.  In these situations, the home network may need
   to know the location of the user in order to enable location-aware
   billing, location-aware authorization, or other location-aware
   services.  Location information can also prove useful in other
   situations (such as wired networks) where operator-network ownership
   and location information may be needed by the home network.

   In order to preserve user privacy, location information needs to be
   protected against unauthorized access and distribution.  Requirements
   for access to location information are defined in [RFC3693].  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.  In Appendix A, the
   requirements for a GEOPRIV using protocol [RFC3693] are compared to
   the functionality provided by this document.

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 [RFC2119].

   RADIUS-specific terminology is borrowed from [RFC2865] and [RFC2866].

   Terminology related to privacy issues, location information, and
   authorization policy rules is taken from [RFC3693].

3.  Delivery Methods for Location Information

   The following exchanges show how location information is conveyed in
   RADIUS.  In describing the usage scenarios, we assume that privacy
   policies allow location to be conveyed in RADIUS; however, as noted
   in Section 6, similar exchanges can also take place within Diameter.
   Privacy issues are discussed in Section 7.2.

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3.1.  Location Delivery Based on Out-of-Band Agreements

   Figure 1 shows an example message flow for delivering location
   information during the network-access authentication and
   authorization procedure.  Upon a network-authentication request from
   an access-network client, the Network Access Server (NAS) submits a
   RADIUS Access-Request message that contains Location-Information
   Attributes among other required attributes.  In this scenario,
   location information is attached to the Access-Request message
   without an explicit request from the RADIUS server.  Note that such
   an approach with a prior agreement between the RADIUS client and the
   RADIUS server is only applicable in certain environments, such as in
   situations where the RADIUS client and server are within the same
   administrative domain.  The Basic-Location-Policy-Rules Attribute is
   populated based on the defaults described in Section 4.4, unless it
   has been explicitly configured otherwise.

    +---------+             +---------+                   +---------+
    |         |             | Network |                   |  RADIUS |
    | User    |             | Access  |                   |  Server |
    |         |             | Server  |                   |         |
    +---------+             +---------+                   +---------+
        |                       |                              |
        | Authentication phase  |                              |
        | begin                 |                              |
        |---------------------->|                              |
        |                       |                              |
        |                       | Access-Request               |
        |                       | + Location-Information       |
        |                       | + Location-Data              |
        |                       | + Basic-Location-Policy-Rules|
        |                       | + Operator-Name              |
        |                       |----------------------------->|
        |                       |                              |
        |                       | Access-Accept                |
        |                       |<-----------------------------|
        | Authentication        |                              |
        | Success               |                              |
        |<----------------------|                              |
        |                       |                              |

        Figure 1: Location Delivery Based on Out-of-Band Agreements

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3.2.  Location Delivery Based on Initial Request

   If the RADIUS client provides a Location-Capable Attribute in the
   Access-Request, then the RADIUS server MAY request location
   information from the RADIUS client if it requires that information
   for authorization and if location information was not provided in the
   Access-Request.  This exchange is shown in Figure 2.  The inclusion
   of the Location-Capable Attribute in an Access-Request message
   indicates that the NAS is capable of providing location data in
   response to an Access-Challenge.  The subsequent Access-Challenge
   message sent from the RADIUS server to the NAS provides a hint
   regarding the type of desired Location-Information Attributes.  The
   NAS treats the Basic-Location-Policy-Rules and Extended-Location-
   Policy-Rules Attributes as opaque data (e.g., it echoes these rules
   provided by the server within the Access-Challenge back in the
   Access-Request).  In the shown message flow, the location attributes
   are then provided in the subsequent Access-Request message.  When
   evaluating this Access-Request message, the authorization procedure
   at the RADIUS server might be based on a number of criteria,
   including the newly defined attributes listed in Section 4.

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   +---------+             +---------+                       +---------+
   |         |             | Network |                       |  RADIUS |
   | User    |             | Access  |                       |  Server |
   |         |             | Server  |                       |         |
   +---------+             +---------+                       +---------+
       |                       |                                  |
       | Authentication phase  |                                  |
       | begin                 |                                  |
       |---------------------->|                                  |
       |                       |                                  |
       |                       | Access-Request                   |
       |                       | + Location-Capable               |
       |                       |--------------------------------->|
       |                       |                                  |
       |                       | Access-Challenge                 |
       |                       |  + Basic-Location-Policy-Rules   |
       |                       |  + Extended-Location-Policy-Rules|
       |                       |  + Requested-Location-Info       |
       |                       |<---------------------------------|
       |                       |                                  |
       |                       | Access-Request                   |
       |                       |  + Location-Information          |
       |                       |  + Location-Data                 |
       |                       |  + Basic-Location-Policy-Rules   |
       |                       |  + Extended-Location-Policy-Rules|
       |                       |--------------------------------->|
       |                       |                                  |
       :                       :                                  :
       :       Multiple Protocol Exchanges to perform             :
       :    Authentication, Key Exchange, and Authorization       :
       :                  ...continued...                         :
       :                       :                                  :
       |                       |                                  |
       |                       | Access-Accept                    |
       |                       |<---------------------------------|
       | Authentication        |                                  |
       | Success               |                                  |
       |<----------------------|                                  |
       |                       |                                  |

           Figure 2: Location Delivery Based on Initial Request

3.3.  Location Delivery Based on Mid-Session Request

   The on-demand, mid-session location-delivery method utilizes the
   Change-of-Authorization Request (CoA-Request) message and the CoA-NAK
   (CoA-Negative Acknowledgement), defined in [RFC5176].  At any time

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   during the session, the Dynamic Authorization Client MAY send a CoA-
   Request containing session-identification attributes to the NAS
   (i.e., Dynamic Authorization Server).

   In order to enable the on-demand, mid-session location-delivery
   method, the RADIUS server MUST return an instance of the Requested-
   Location-Info Attribute with the 'FUTURE_REQUESTS' flag set and
   instances of the Basic-Location-Policy-Rules and Extended-Location-
   Policy-Rules Attributes in the Access-Accept message for the session.
   Upon receipt of a CoA-Request message containing a Service-Type
   Attribute with value "Authorize Only" for the same session, the NAS
   MUST include location information and echo the previously received
   Basic-Location-Policy-Rules and Extended-Location-Policy-Rules
   Attributes in the subsequent Access-Request message.

   Upon receiving the Access-Request message containing the Service-Type
   Attribute with a value of Authorize-Only from the NAS, the RADIUS
   server responds with either an Access-Accept or an Access-Reject
   message.

   The use of dynamic authorization [RFC5176] is necessary when location
   information is needed on-demand and cannot be obtained from
   accounting information in a timely fashion.

   Figure 3 shows the above-described approach graphically.

  +---------------+                        +---------------+    +------+
  | Dynamic       |                        | Dynamic       |    |RADIUS|
  | Authorization |                        | Authorization |    |Server|
  | Server/NAS    |                        | Client        |    |      |
  +---------------+                        +---------------+    +------+
      |                                             |              |
      |  Access-Request                             |              |
      |  + Location-Capable                         |              |
      |----------------------------------------------------------->|
      |                                             |              |
      |  Access-Challenge                           |              |
      |   + Basic-Location-Policy-Rules             |              |
      |   + Extended-Location-Policy-Rules          |              |
      |   + Requested-Location-Info                 |              |
      |<-----------------------------------------------------------|
      |                                             |              |
      |  Access-Request                             |              |
      |   + Location-Information                    |              |
      |   + Location-Data                           |              |
      |   + Basic-Location-Policy-Rules             |              |
      |   + Extended-Location-Policy-Rules          |              |
      |----------------------------------------------------------->|

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      |                                             |              |
      |                                             |              |
      :                                             |              :
      :       Multiple Protocol Exchanges to perform               :
      :    Authentication, Key Exchange, and Authorization         :
      :                  ...continued...            |              :
      :                                             |              :
      |                                             |              |
      |                                             |              |
      |  Access-Accept                              |              |
      |      + Requested-Location-Info              |              |
               (FUTURE_REQUESTS,...)                |              |
      |      + Basic-Location-Policy-Rules          |              |
      |      + Extended-Location-Policy-Rules       |              |
      |<-----------------------------------------------------------|
      |                                             |              |
      :                                             :              :
      :                <<Some time later>>          :              :
      :                                             :              :
      |                                             |              |
      | CoA + Service-Type "Authorize Only" + State |              |
      |<--------------------------------------------|              |
      |                                             |              |
      |  CoA NAK + Service-Type "Authorize Only"    |              |
      |          + State                            |              |
      |          + Error-Cause  "Request Initiated" |              |
      |-------------------------------------------->|              |
      |                                             |              |
      |  Access-Request                             |              |
      |          + Service-Type "Authorize Only"    |              |
      |          + State                            |              |
      |          + Location-Information             |              |
      |          + Location-Data                    |              |
      |          + Basic-Location-Policy-Rules      |              |
      |          + Extended-Location-Policy-Rules   |              |
      |----------------------------------------------------------->|
      |  Access-Accept                              |              |
      |<-----------------------------------------------------------|
      |                                             |              |

               Figure 3: Location Delivery Based on CoA with
                       Service-Type 'Authorize Only'

   When the Dynamic Authorization Client wants to change the values of
   the requested location information, or set the values of the
   requested location information for the first time, it may do so
   without triggering a reauthorization.  Assuming that the NAS had
   previously sent an Access-Request containing a Location-Capable

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   Attribute, the Dynamic Authorization Client (DAC) can send a CoA-
   Request to the NAS without a Service-Type Attribute, but include the
   NAS identifiers and session identifiers as per [RFC5176] and the
   Requested-Location-Info, Basic-Location-Policy-Rules, and Extended-
   Location-Policy-Rules Attributes.  The Requested-Location-Info,
   Basic-Location-Policy-Rules, and Extended-Location-Policy-Rules
   Attributes MUST NOT be used for session identification.

   Figure 4 shows this approach graphically.

  +---------------+                        +---------------+    +------+
  | Dynamic       |                        | Dynamic       |    |RADIUS|
  | Authorization |                        | Authorization |    |Server|
  | Server/NAS    |                        | Client        |    |      |
  +---------------+                        +---------------+    +------+
      |                                             |              |
      |                                             |              |
      |  Access-Request                             |              |
      |  + Location-Capable                         |              |
      |----------------------------------------------------------->|
      |                                             |              |
      |  Access-Challenge                           |              |
      |   + Basic-Location-Policy-Rules             |              |
      |   + Extended-Location-Policy-Rules          |              |
      |   + Requested-Location-Info                 |              |
      |<-----------------------------------------------------------|
      |                                             |              |
      |  Access-Request                             |              |
      |   + Location-Information                    |              |
      |   + Location-Data                           |              |
      |   + Basic-Location-Policy-Rules             |              |
      |   + Extended-Location-Policy-Rules          |              |
      |----------------------------------------------------------->|
      |                                             |              |
      |                                             |              |
      :                                             |              :
      :       Multiple Protocol Exchanges to perform               :
      :    Authentication, Key Exchange, and Authorization         :
      :                  ...continued...            |              :
      :                                             |              :
      |                                             |              |
      |                                             |              |
      |  Access-Accept                              |              |
      |      + Requested-Location-Info              |              |
      |      + Basic-Location-Policy-Rules          |              |
      |      + Extended-Location-Policy-Rules       |              |
      |<-----------------------------------------------------------|

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      |                                             |              |
      :                                             :              :
      :                <<Some time later>>          :              :
      :                                             :              :
      |                                             |              |
      |  CoA                                        |              |
      |      + Requested-Location-Info              |              |
      |      + Basic-Location-Policy-Rules          |              |
      |      + Extended-Location-Policy-Rules       |              |
      |<--------------------------------------------|              |
      |                                             |              |
      |  CoA ACK                                    |              |
      |-------------------------------------------->|              |
      |                                             |              |
      :                                             :              :
      :           <<Further exchanges later>>       :              :
      :                                             :              :

                 Figure 4: Location Delivery Based on CoA

3.4.  Location Delivery in Accounting Messages

   Location information may also be reported in accounting messages.
   Accounting messages are generated when the session starts, when the
   session stops, and periodically during the lifetime of the session.
   Accounting messages may also be generated when the user roams during
   handoff.

   Accounting information may be needed by the billing system to
   calculate the user's bill.  For example, there may be different
   tariffs or tax rates applied based on the location.

   If the RADIUS server needs to obtain location information in
   accounting messages, then it needs to include a Requested-Location-
   Info Attribute with the Access-Accept message.  The Basic-Location-
   Policy-Rules and the Extended-Location-Policy-Rules Attributes are to
   be echoed in the Accounting-Request if indicated in the Access-
   Accept.

   Figure 5 shows the message exchange.

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   +---------+             +---------+                       +---------+
   |         |             | Network |                       | RADIUS  |
   | User    |             | Access  |                       | Server  |
   |         |             | Server  |                       |         |
   +---------+             +---------+                       +---------+
       |                       |                                  |
       :                       :                                  :
       :          Initial Protocol Interaction                    :
       :          (details omitted)                               :
       :                       :                                  :
       |                       |                                  |
       |                       | Access-Accept                    |
       |                       |  + Requested-Location-Info       |
       |                       |  + Basic-Location-Policy-Rules   |
       |                       |  + Extended-Location-Policy-Rules|
       |                       |<---------------------------------|
       | Authentication        |                                  |
       | Success               |                                  |
       |<----------------------|                                  |
       |                       |                                  |
       |                       | Accounting-Request               |
       |                       |  + Location-Information          |
       |                       |  + Location-Data                 |
       |                       |  + Basic-Location-Policy-Rules   |
       |                       |  + Extended-Location-Policy-Rules|
       |                       |--------------------------------->|
       |                       |                                  |
       |                       | Accounting-Response              |
       |                       |<---------------------------------|
       |                       |                                  |

            Figure 5: Location Delivery in Accounting Messages

4.  Attributes

   It is important to note that the location-specific parts of the
   attributes defined below are not meant to be processed by the RADIUS
   server.  Instead, a location-server-specific component used in
   combination with the RADIUS server is responsible for receiving,
   processing, and further distributing location information (in
   combination with proper access control and privacy protection).  As
   such, from a RADIUS server point of view, location information is
   treated as opaque data.

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4.1.  Operator-Name Attribute

   This attribute carries the operator namespace identifier and the
   operator name.  The operator name is combined with the namespace
   identifier to uniquely identify the owner of an access network.  The
   value of the Operator-Name is a non-NULL terminated text whose length
   MUST NOT exceed 253 bytes.

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

   A summary of the Operator-Name 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     |            Text              ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |       Text (cont.)                                           ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type:

      126 - Operator-Name

   Length:

      >= 4

   Text:

      The format is shown below.  The data type of this field is a text.
      All fields are transmitted from left to right:

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Namespace ID  | Operator-Name                                ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Operator-Name                                                ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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   Namespace ID:

      The value within this field contains the operator namespace
      identifier.  The Namespace ID value is encoded in ASCII.

      Example: '1' (0x31) for REALM

   Operator-Name:

      The text field of variable length contains an Access Network
      Operator Name.  This field is a RADIUS-based data type of Text.

   The Namespace ID field provides information about the operator
   namespace.  This document defines four values for this attribute,
   which are listed below.  Additional namespace identifiers must be
   registered with IANA (see Section 8.1) and must be associated with an
   organization responsible for managing the namespace.

   TADIG ('0' (0x30)):

      This namespace can be used to indicate operator names based on
      Transferred Account Data Interchange Group (TADIG) codes, as
      defined in [GSM].  TADIG codes are assigned by the TADIG Working
      Group within the Global System for Mobile Communications (GSM)
      Association.  The TADIG code consists of two fields, with a total
      length of five ASCII characters consisting of a three-character
      country code and a two-character alphanumeric operator (or
      company) ID.

   REALM ('1' (0x31)):

      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).  Since this
      operator is limited to ASCII, any registered domain name that
      contains non-ASCII characters must be converted to ASCII.  The
      Punycode encoding [RFC3492] is used for this purpose.

   E212 ('2' (0x32)):

      The E212 namespace can be used to indicate operator names based on
      the Mobile Country Code (MCC) and Mobile Network Code (MNC)
      defined in [ITU212].  The MCC/MNC values are assigned by the
      Telecommunications Standardization Bureau (TSB) within the ITU-T

Top      ToC       Page 14 
      and by designated administrators in different countries.  The E212
      value consists of three ASCII digits containing the MCC, followed
      by two or three ASCII digits containing the MNC.

   ICC ('3' (0x33)):

      The ICC namespace can be used to indicate operator names based on
      International Telecommunication Union (ITU) Carrier Codes (ICC)
      defined in [ITU1400].  ICC values are assigned by national
      regulatory authorities and are coordinated by the
      Telecommunication Standardization Bureau (TSB) within the ITU
      Telecommunication Standardization Sector (ITU-T).  When using the
      ICC namespace, the attribute consists of three uppercase ASCII
      characters containing a three-letter alphabetic country code, as
      defined in [ISO], followed by one to six uppercase alphanumeric
      ASCII characters containing the ICC itself.

4.2.  Location-Information Attribute

   The Location-Information Attribute MAY be sent in the Access-Request
   message, the Accounting-Request message, both of these messages, or
   no message.  For the Accounting-Request message, the Acc-Status-Type
   may be set to Start, Interim, or Stop.

   The Location-Information Attribute provides meta-data about the
   location information, such as sighting time, time-to-live, location-
   determination method, etc.

   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     |            String            ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |       String (cont.)                                         ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type:

      127 - Location-Information

   Length:

      >= 23

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   String:

      The format is shown below.  The data type of this field is a
      string.  All fields are transmitted from left to right:

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   Index                       | Code          |  Entity       |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Sighting Time                                                 ~
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Sighting Time                                                 |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Time-to-Live                                                 ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Time-to-Live                                                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   Method                                                     ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Index (16 bits):

      The 16-bit unsigned integer value allows this attribute to provide
      information relating to the information included in the Location-
      Data Attribute to which it refers (via the Index).

   Code (8 bits):

      This field indicates the content of the location profile carried
      in the Location-Data Attribute.  Two profiles are defined in this
      document -- namely, a civic location profile (see Section 4.3.1)
      that uses value (0) and a geospatial location profile (see
      Section 4.3.2) that uses the value (1).

   Entity (8 bits):

      This field encodes which location this attribute refers to as an
      unsigned 8-bit integer value.  Location information can refer to
      different entities.  This document registers two entity values,
      namely:

         Value (0) describes the location of the user's client device.

         Value (1) describes the location of the RADIUS client.

      The registry used for these values is established by this
      document, see Section 8.4.

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   Sighting Time (64 bits)

      This field indicates when the location information was accurate.
      The data type of this field is a string, and the content is
      expressed in the 64-bit Network Time Protocol (NTP) timestamp
      format [RFC1305].

   Time-to-Live (64 bits):

      This field gives a hint regarding for how long location
      information should be considered current.  The data type of this
      field is a string and the content is expressed in the 64-bit
      Network Time Protocol (NTP) timestamp format [RFC1305].  Note that
      the Time-to-Live field is different than the Retention Expires
      field used in the Basic-Location-Policy-Rules Attribute, see
      Section 4.4.  The Retention Expires field indicates the time the
      recipient is no longer permitted to possess the location
      information.

   Method (variable):

      Describes the way that the location information was determined.
      This field MUST contain the value of exactly one IANA-registered
      'method' token [RFC4119].

   The length of the Location-Information Attribute MUST NOT exceed 253
   octets.

4.3.  Location-Data Attribute

   The Location-Data Attribute MAY be sent in Access-Request and
   Accounting-Request messages.  For the Accounting-Request message, the
   Acc-Status-Type may be set to Start, Interim, or Stop.

   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     |            String            ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |       String (cont.)                                         ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type:

      128 - Location-Data

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   Length:

      >= 5

   String:

      The format is shown below.  The data type of this field is a
      string.  All fields are transmitted from left to right:

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   Index                       |  Location                    ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Location                                                    ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Index (16 bits):

      The 16-bit unsigned integer value allows this attribute to
      associate the Location-Data Attribute with the Location-
      Information Attributes.

   Location (variable):

      The format of the location data depends on the location profile.
      This document defines two location profiles.  Details of the
      location profiles are described below.

4.3.1.  Civic Location Profile

   Civic location is a popular way to describe the location of an
   entity.  This section defines the civic location-information profile
   corresponding to the value (0) indicated in the Code field of the
   Location-Information Attribute.  The location format is based on the
   encoding format defined in Section 3.1 of [RFC4776], whereby the
   first 3 octets are not put into the Location field of the above-
   described RADIUS Location-Data Attribute (i.e., the code for the DHCP
   option, the length of the DHCP option, and the 'what' element are not
   included).

4.3.2.  Geospatial Location Profile

   This section defines the geospatial location-information profile
   corresponding to the value (1) indicated in the Code field of the
   Location-Information Attribute.  Geospatial location information is
   encoded as an opaque object, and the format is based on the Location

Top      ToC       Page 18 
   Configuration Information (LCI) format defined in Section 2 of
   [RFC3825] but starts with the third octet (i.e., the code for the
   DHCP option and the length field is not included).

4.4.  Basic-Location-Policy-Rules Attribute

   The Basic-Location-Policy-Rules Attribute MAY be sent in Access-
   Request, Access-Accept, Access-Challenge, Change-of-Authorization,
   and Accounting-Request messages.

   Policy rules control the distribution of location information.  In
   order to understand and process the Basic-Location-Policy-Rules
   Attribute, RADIUS clients are obligated to utilize a default value of
   Basic-Location-Policy-Rules, unless explicitly configured otherwise,
   and to echo the Basic-Location-Policy-Rules Attribute that they
   receive from a server.  As a default, the Note Well field does not
   carry a pointer to human-readable privacy policies, the
   retransmission-allowed is set to zero (0), i.e., further distribution
   is not allowed, and the Retention Expires field is set to 24 hours.

   With regard to authorization policies, this document reuses work done
   in [RFC4119] and encodes those policies in a 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 [RFC3693], Section 2.7.

   The format of the Basic-Location-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     |            String            ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |       String (cont.)                                         ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type:

      129 - Basic-Location-Policy-Rules

   Length:

      >= 12

Top      ToC       Page 19 
   String:

      The format is shown below.  The data type of this field is a
      string.  All fields are transmitted from left to right:

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Flags                        | Retention Expires            ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Retention Expires                                            ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Retention Expires             | Note Well                    ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Note Well                                                    ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   This document reuses fields from the RFC 4119 [RFC4119] 'usage-rules'
   element.  These fields have the following meaning:

   Flags (16 bits):

      The Flags field is a bit mask.  Only the first bit (R) is defined
      in this document, and it corresponds to the Retransmission Allowed
      field:

        0                   1
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |R|o o o o o o o o o o o o o o o|
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

       R = Retransmission Allowed
       o = reserved.

   All reserved bits MUST be zero.  When the value of the Retransmission
   Allowed field is set to zero (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 this attribute to share the location information with other
   parties by considering the extended policy rules.

   Retention Expires (64 bits):

      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 [RFC1305].

Top      ToC       Page 20 
   Note Well (variable):

      This field contains a URI that points to human-readable privacy
      instructions.  The data type of this field is a string.  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 RADIUS ecosystem, 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 into
      the 'note-well' element of the 'usage-rules' element contained in
      the PIDF-LO (Presence Information Data Format - Location Object)
      document (see [RFC4119]).  The Note Well field may be empty.

4.5.  Extended-Location-Policy-Rules Attribute

   The Extended-Location-Policy-Rules Attribute MAY be sent in Access-
   Request, Access-Accept, Access-Challenge, Access-Reject, Change-of-
   Authorization, and Accounting-Request messages.

   The Ruleset Reference field of this attribute is of variable length.
   It contains a URI that indicates where the richer ruleset can be
   found.  This URI SHOULD use the HTTPS URI scheme.  As a deviation
   from [RFC4119], this field only contains a reference and does not
   carry an attached, extended ruleset.  This modification is motivated
   by the size limitations imposed by RADIUS.

   In order to understand and process the Extended-Location-Policy-Rules
   Attribute, RADIUS clients are obligated to attach the URI to the
   Extended-Location-Policy-Rules Attribute when they are explicitly
   configured to do so, and to echo the Extended-Location-Policy-Rules
   Attribute that they receive from a server.  There is no expectation
   that RADIUS clients will need to retrieve data at the URL specified
   in the attribute or to parse the XML policies.

   The format of the Extended-Location-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     |            String            ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |       String (cont.)                                         ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Top      ToC       Page 21 
   Type:

      130 - Extended-Location-Policy-Rules

   Length:

      >= 3

   String:

      This field is at least two octets in length, and the format is
      shown below.  The data type of this field is a string.  The fields
      are transmitted from left to right:

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |    Ruleset Reference                                         ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Ruleset Reference:

      This field contains a URI that points to the policy rules.

4.6.  Location-Capable Attribute

   The Location-Capable Attribute allows an NAS (or client function of a
   proxy server) to indicate support for the functionality specified in
   this document.  The Location-Capable Attribute with the value for
   'Location Capable' MUST be sent with the Access-Request messages, if
   the NAS supports the functionality described in this document and is
   capable of sending location information.  A RADIUS server MUST NOT
   challenge for location information unless the Location-Capable
   Attribute has been sent to it.

      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        | Integer                       |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |       Integer (cont.)         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type:

      131 - Location-Capable Attribute

Top      ToC       Page 22 
   Length:

      6

   Integer:

      The content of the Integer field encodes the requested
      capabilities.  Each capability value represents a bit position.

   This document specifies the following capabilities.

   Name:

      CIVIC_LOCATION

   Description:

      The RADIUS client uses the CIVIC_LOCATION to indicate that it is
      able to return civic location based on the location profile
      defined in Section 4.3.1.

   Numerical Value:

      A numerical value of this token is '1'.

   Name:

      GEO_LOCATION

   Description:

      The RADIUS client uses the GEO_LOCATION to indicate that it is
      able to return geodetic location based on the location profile
      defined in Section 4.3.2.

   Numerical Value:

      A numerical value of this token is '2'.

   Name:

      USERS_LOCATION

Top      ToC       Page 23 
   Description:

      The numerical value representing USERS_LOCATION indicates that the
      RADIUS client is able to provide a Location-Information Attribute
      with the Entity Attribute expressing the value of zero (0), i.e.,
      the RADIUS client is capable of returning the location information
      of the user's client device.

   Numerical Value:

      A numerical value of this token is '4'.

   Name:

      NAS_LOCATION

   Description:

      The numerical value representing NAS_LOCATION indicates that the
      RADIUS client is able to provide a Location-Information Attribute
      that contains location information with the Entity Attribute
      expressing the value of one (1), i.e., the RADIUS client is
      capable of returning the location information of the NAS.

   Numerical Value:

      A numerical value of this token is '8'.

4.7.  Requested-Location-Info Attribute

   The Requested-Location-Info Attribute allows the RADIUS server to
   indicate which location information about which entity it wants to
   receive.  The latter aspect refers to the entities that are indicated
   in the Entity field of the Location-Information Attribute.

   The Requested-Location-Info Attribute MAY be sent in an Access-
   Accept, Access-Challenge, or Change-of-Authorization packet.

   If the RADIUS server wants to dynamically decide on a per-request
   basis to ask for location information from the RADIUS client, then
   the following cases need to be differentiated.  If the RADIUS client
   and the RADIUS server have agreed out-of-band to mandate the transfer
   of location information for every network-access authentication
   request, then the processing listed below is not applicable.

Top      ToC       Page 24 
   o  If the RADIUS server requires location information for computing
      the authorization decision and the RADIUS client does not provide
      it with the Access-Request message, then the Requested-Location-
      Info Attribute is attached to the Access-Challenge with a hint
      about what is required.

   o  If the RADIUS server does not receive the requested information in
      response to the Access-Challenge (including the Requested-
      Location-Info Attribute), then the RADIUS server may respond with
      an Access-Reject message with an Error-Cause Attribute (including
      the "Location-Info-Required" value).

   o  If the RADIUS server would like location information in the
      Accounting-Request message but does not require it for computing
      an authorization decision, then the Access-Accept message MUST
      include a Required-Info Attribute.  This is typically the case
      when location information is used only for billing.  The RADIUS
      client SHOULD attach location information, if available, to the
      Accounting-Request (unless authorization policies dictate
      something different).

   If the RADIUS server does not send a Requested-Location-Info
   Attribute, then the RADIUS client MUST NOT attach location
   information to messages towards the RADIUS server.  The user's
   authorization policies, if available, MUST be consulted by the RADIUS
   server before requesting location information delivery from the
   RADIUS client.

   Figure 6 shows a simple protocol exchange where the RADIUS server
   indicates the desire to obtain location information, namely civic
   location information of the user, to grant access.  Since the
   Requested-Location-Info Attribute is attached to the Access-
   Challenge, the RADIUS server indicates that location information is
   required for computing an authorization decision.

Top      ToC       Page 25 
    +---------+                        +---------+
    | RADIUS  |                        | RADIUS  |
    | Client  |                        | Server  |
    +---------+                        +---------+
         |                                  |
         |                                  |
         | Access-Request                   |
         | + Location-Capable               |
         |   ('CIVIC_LOCATION',             |
         |    'GEO_LOCATION',               |
         |    'NAS_LOCATION',               |
         |    'USERS_LOCATION')             |
         |--------------------------------->|
         |                                  |
         | Access-Challenge                 |
         | + Requested-Location-Info        |
         |   ('CIVIC_LOCATION',             |
         |    'USERS_LOCATION')             |
         | + Basic-Location-Policy-Rules    |
         | + Extended-Location-Policy-Rules |
         |<---------------------------------|
         |                                  |
         | Access-Request                   |
         | + Location-Information           |
         | + Location-Data                  |
         | + Basic-Location-Policy-Rules    |
         | + Extended-Location-Policy-Rules |
         |--------------------------------->|
         |                                  |
         |        ....                      |

          Figure 6: RADIUS Server Requesting Location Information

   The Requested-Location-Info Attribute MUST be sent by the RADIUS
   server, in the absence of an out-of-band agreement, if it wants the
   RADIUS client to return location information and if authorization
   policies permit it.  This Requested-Location-Info Attribute MAY
   appear in the Access-Accept or in the Access-Challenge message.

   A summary of the 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     |            Integer           ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |       Integer (cont.)         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Top      ToC       Page 26 
   Type:

      132 - Requested-Location-Info Attribute

   Length:

      6

   Integer:

      The content of the Integer field encodes the requested information
      attributes.  Each capability value represents a bit position.

   This document specifies the following capabilities:

   Name:

      CIVIC_LOCATION

   Description:

      The RADIUS server uses the Requested-Location-Info Attribute with
      the value set to CIVIC_LOCATION to request specific location
      information from the RADIUS client.  The numerical value
      representing CIVIC_LOCATION requires the RADIUS client to attach
      civic location attributes.  CIVIC_LOCATION refers to the location
      profile defined in Section 4.3.1.

   Numerical Value:

      A numerical value of this token is '1'.

   Name:

      GEO_LOCATION

   Description:

      The RADIUS server uses the Requested-Location-Info Attribute with
      the value set to GEO_LOCATION to request specific location
      information from the RADIUS client.  The numerical value
      representing GEO_LOCATION requires the RADIUS client to attach
      geospatial location attributes.  GEO_LOCATION refers to the
      location profile described in Section 4.3.2.

   Numerical Value:

      A numerical value of this token is '2'.

Top      ToC       Page 27 
   Name:

      USERS_LOCATION

   Description:

      The numerical value representing USERS_LOCATION indicates that the
      RADIUS client MUST send a Location-Information Attribute with the
      Entity Attribute expressing the value of zero (0).  Hence, there
      is a one-to-one relationship between the USERS_LOCATION token and
      the value of zero (0) of the Entity Attribute inside the Location-
      Information Attribute.  A value of zero indicates that the
      location information in the Location-Information Attribute refers
      to the user's client device.

   Numerical Value:

      A numerical value of this token is '4'.

   Name:

      NAS_LOCATION

   Description:

      The numerical value representing NAS_LOCATION indicates that the
      RADIUS client MUST send a Location-Information Attribute that
      contains location information with the Entity Attribute expressing
      the value of one (1).  Hence, there is a one-to-one relationship
      between the NAS_LOCATION token and the value of one (1) of the
      Entity Attribute inside the Location-Information Attribute.  A
      value of one indicates that the location information in the
      Location-Information Attribute refers to the RADIUS client.

   Numerical Value:

      A numerical value of this token is '8'.

   Name:

      FUTURE_REQUESTS

   Description:

      The numerical value representing FUTURE_REQUESTS indicates that
      the RADIUS client MUST provide future Access-Requests for the same
      session with the same type of information as returned in the
      initial Access-Request message.

Top      ToC       Page 28 
   Numerical Value:

      A numerical value of this token is '16'.

   Name:

      NONE

   Description:

      The RADIUS server uses this token to request that the RADIUS
      client stop sending location information.

   Numerical Value:

      A numerical value of this token is '32'.

   If neither the NAS_LOCATION nor the USERS_LOCATION bit is set, then
   per-default the location of the user's client device is returned (if
   authorization policies allow it).  If both the NAS_LOCATION and the
   USERS_LOCATION bits are set, then the returned location information
   has to be put into separate attributes.  If neither the
   CIVIC_LOCATION nor the GEO_LOCATION bit is set in the Requested-
   Location-Info Attribute, then no location information is returned.
   If both the CIVIC_LOCATION and the GEO_LOCATION bits are set, then
   the location information has to be put into separate attributes.  The
   value of NAS_LOCATION and USERS_LOCATION refers to the location
   information requested via CIVIC_LOCATION and GEO_LOCATION.

   As an example, if the bits for NAS_LOCATION, USERS_LOCATION, and
   GEO_LOCATION are set, then the location information of the RADIUS
   client and the users' client device are returned in a geospatial-
   location format.



(page 28 continued on part 2)

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