RFC 5580
Carrying Location Objects in RADIUS and Diameter
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 DiameterAbstract
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.
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
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.
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
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.
+---------+ +---------+ +---------+ | | | 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 Request3.3. 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
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 | | |----------------------------------------------------------->|
| | | | | | : | : : 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
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 | | |<-----------------------------------------------------------|
| | | : : : : <<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 CoA3.4. 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.
+---------+ +---------+ +---------+ | | | 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 Messages4. 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.
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 ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
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
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.
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
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
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
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].
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.) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
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
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.
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.
+---------+ +---------+ | 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.) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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'.
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.
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)
