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RFC 5580

Carrying Location Objects in RADIUS and Diameter

Pages: 53
Proposed Standard
Errata
Updated by:  8559
Part 1 of 2 – Pages 1 to 28
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Top   ToC   RFC5580 - Page 1
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.
Top   ToC   RFC5580 - Page 2

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
Top   ToC   RFC5580 - Page 3

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.
Top   ToC   RFC5580 - Page 4

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
Top   ToC   RFC5580 - Page 5

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.
Top   ToC   RFC5580 - Page 6
   +---------+             +---------+                       +---------+
   |         |             | 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
Top   ToC   RFC5580 - Page 7
   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          |              |
      |----------------------------------------------------------->|
Top   ToC   RFC5580 - Page 8
      |                                             |              |
      |                                             |              |
      :                                             |              :
      :       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
Top   ToC   RFC5580 - Page 9
   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       |              |
      |<-----------------------------------------------------------|
Top   ToC   RFC5580 - Page 10
      |                                             |              |
      :                                             :              :
      :                <<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.
Top   ToC   RFC5580 - Page 11
   +---------+             +---------+                       +---------+
   |         |             | 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.
Top   ToC   RFC5580 - Page 12

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 ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Top   ToC   RFC5580 - Page 13
   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   RFC5580 - 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
Top   ToC   RFC5580 - Page 15
   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.
Top   ToC   RFC5580 - Page 16
   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
Top   ToC   RFC5580 - Page 17
   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   RFC5580 - 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   RFC5580 - 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   RFC5580 - 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   RFC5580 - 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   RFC5580 - 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   RFC5580 - 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   RFC5580 - 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   RFC5580 - 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   RFC5580 - 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   RFC5580 - 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   RFC5580 - 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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