Geopriv H. Tschofenig Internet-Draft Siemens Expires:
January 17,August 16, 2006 F. Adrangi Intel M. Jones A. Lior Bridgewater July 16, 2005February 12, 2006 Carrying Location Objects in RADIUS draft-ietf-geopriv-radius-lo-04.txtdraft-ietf-geopriv-radius-lo-05.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on January 17,August 16, 2006. Copyright Notice Copyright (C) The Internet Society (2005).(2006). Abstract This document describes RADIUS attributes for conveying access network ownership and location information based on a civic and geospatial location format. The distribution of location information is a privacy sensitive task. Dealing with mechanisms to preserve the user's privacy is important and addressed in this document. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 54 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 65 3. Delivery Methods for Location Information . . . . . . . . . . 7 3.16 3.1. Authentication/Authorization Phase Delivery . . . . . . . 7 3.26 3.2. Mid-session Authorization . . . . . . . . . . . . . . . . 89 4. Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4.14.1. Scenario 1 - Use of Location Information in AAA . . . . . 10 4.24.2. Scenario 2 - Use of Location Information for Other Services . . . . . . . . . . . . . . . . . . . . . . . . . 1011 5. Overview . . . . . . . . . . . . . . . . . . . . . . . .Description of Attributes . . . 12 5.1 Operator-Namespace Attribute. . . . . . . . . . . . . . . 12 5.25.1. Operator-Name Attribute . . . . . . . . . . . . . . . . . 12 5.35.2. Location-Information Attribute . . . . . . . . . . . . . . 13 126.96.36.199.1. Civic Location Information . . . . . . . . . . . . . . 13 188.8.131.52.2. Geospatial Location Information . . . . . . . . . . . 15 6. Basic- and Extended-Policy-Rule Attributes . . . . . . . . . . 16 7. Location-TypeRequested-Info Attribute . . . . . . . . . . . . . . . . . . . 17 8. Capability Attribute . . . . . . . . . . . . . . . . . . . . . 18 9.Diameter RADIUS Interoperability . . . . . . . . . . . . . . . 20 10.19 9. Attributes . . . . . . . . . . . . . . . . . . . . . . . . . 21 10.1 Operator-Namespace Attribute . . . . . . . . . . . . . .. 21 10.220 9.1. Operator-Name Attribute . . . . . . . . . . . . . . . . . 21 10.320 9.2. Location-Information Attribute . . . . . . . . . . . . . . 22 10.420 9.3. Basic Policy Rules Attribute . . . . . . . . . . . . . . . 26 10.525 9.4. Extended Policy Rules Attribute . . . . . . . . . . . . . 27 10.6 Location-Type26 9.5. Challenge-Capable Attribute . . . . . . . . . . . . . . . . . 28 10.7 Capability27 9.6. Requested-Info Attribute . . . . . . . . . . . . . . . . . . . 28 11.27 10. Table of Attributes . . . . . . . . . . . . . . . . . . . . . 31 12.11. Matching with Geopriv Requirements . . . . . . . . . . . . . . 32 12.111.1. Distribution of Location Information at the User's Home Network . . . . . . . . . . . . . . . . . . . . . . . 32 12.211.2. Distribution of Location Information at the Visited Network . . . . . . . . . . . . . . . . . . . . . . . . . 33 12.311.3. Requirements matching . . . . . . . . . . . . . . . . . . 34 13.12. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 14.13. Privacy Considerations . . . . . . . . . . . . . . . . . . . . 42 14.113.1. Entity in the visited network . . . . . . . . . . . . . . 42 14.213.2. Entity in the home network . . . . . . . . . . . . . . . . 43 15.14. Security Considerations . . . . . . . . . . . . . . . . . . . 46 16.15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 49 16.115.1. New Registry: Operator Type . . . . . . . . . . . . . . . 49 16.215.2. New Registry: Capabilities . . . . . .Requested-Info attribute . . . . . . . . . . 49 17.50 16. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 51 18.17. References . . . . . . . . . . . . . . . . . . . . . . . . . 52 18.1. 53 17.1. Normative References . . . . . . . . . . . . . . . . . . . 52 18.253 17.2. Informative References . . . . . . . . . . . . . . . . . . 5253 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 55. . 56 Intellectual Property and Copyright Statements . . . . . . . . 56. . 57 1. Introduction Wireless LAN (WLAN) access networks are being deployed in public places such as airports, hotels, shopping malls, and coffee shops by a diverse set of operators such as cellular network operators (GSM and CDMA), Wireless Internet Service Providers (WISPs), and fixed broadband operators. When a user executes the network access authentication procedure to such a network, information about the location and ownership of this network needs to be conveyed to the user's home network to which the user has a contractual relationship. The main intent of this document is to enable location aware billing (e.g., determine the appropriate tariff and taxation in dependence of the location of the access network/user), location aware subscriber authentication and authorization for roaming environments and to enable other location aware services. This document describes AAA attributes that are used by a AAA client or a local AAA server in an access network for conveying location- related information to the user's home AAA server. This document defines attributes for RADIUS . Although the proposed attributes in this draft are intended for wireless LAN deployments, they can also be used in other types of wireless and wired networks whenever location information is required. Location information needs to be protected against unauthorized access and distribution to preserve the user's privacy with regard to location information.  defines requirements for a protocol- independent model for the access to geographic location information. The model includes a Location Generator (LG) that creates location information, a Location Server (LS) that authorizes access to location information, a Location Recipient (LR) that requests and receives information, and a Rule Maker (RM) that provides authorization policies to the LS which enforces access control policies on requests to location information. Althougth this document focuses on the use cases of location based authorization, charging, billing and taxation for network access RADIUS might also be used for location-based authorization for application layer services as well. The extensions defined in this document are therefore not only applicable to a network access scenario. A further description of these scenarios is outside the scope of this document.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 . RADIUS specific terminology is borrowed from  and . Terminology related to privacy issues, location information and authorization policy rules is taken from .. Based on today's protocols we assume that the location information is provided by the access network where the end host is attached. As part of the network attachment, which includes the execution of an authentication and authorization protocol exchange,attachment authentication to the home network is accomplished.provided. The authenticated identity canmight refer to a user, a device or something else. Although there might often be a user associated with the authentication process (either directly or indirectly; indirectly when a binding between a device and a user exists) there is no assurance that a particular real-world entity (such as a person) triggered this process. Since location based authorization is executed based on the network access authentication of a particular "user" it might be reasonable to talk about user's privacy within this document even though scenarios exist where this might not apply (and device or network privacy might be the correct term). Furthermore, the authors believe that there is a relationship between the location ofNAS (or other nodes in the networkaccess network) and the location of the entity that triggered the network access authentication.authentication, such as the user. Knowing the location of a network (where the user or end host is attached to) might in many networks also reveal the location of the user or end host. In some networks it is even possible to provide aaccurate location of the user or end host. A similar assumption is also made with regard to the location information obtained via DHCP (see for example ). This information might be used by applications in other protocols (such as SIP  with extensions )) to indicate the location of a particular user even though the location "only" refers to the location of the network or equipment within the network. The assumption here is also that the location of the network has some relationship to the location of the end host (and subsequently to a user). ThisThis assumption might not hold in all scenarios. Nevertheless, itscenarios but seems to be reasonable.reasonable and practicable. Please note that the authors use the terms end host and user interchangably with respect to the used identities as part of the network access authentication. The term 'user' is used whenever the privacy of the user could potentially be compromised. 3. Delivery Methods for Location Information Location Objects, which consist of location information and privacy rules, are transported over the RADIUS protocol from the visited access network to the home AAA server. To embed a Location Object into RADIUS a number of AVPsattribute are used, such as Location-Information AVP,Location- Information attribute, Basic-Policy-Rules AVP, Extended-Policy-Rules AVP, Location-Type AVP, Operator-Namespace AVP andattribute, Extended-Policy- Rules attribute, Operator-Name AVP.attribute. These AVPsattributes can be delivered to the RADIUS server during the authentication/ authorization phase described in Section 3.1, or in the mid-session using the dynamic authorization protocol framework described in Section 3.2. This section describes messages flowflows for both delivery methods. 3.13.1. Authentication/Authorization Phase Delivery Figure 1 shows an example message flow for delivering location information during the network access authentication/authorization procedure. Upon a network authentication request from an access network client, the NAS submits a RADIUS Access-Request message which contains location information attributes among other required attributes. The attributes (including location information) are added based on some criteria, such as local policy and business relationship with subscriber's home network provider. If no location information is attached although required by the aaa server an error message is returned. The authentication and/or authorization procedure is completed based on a number of criteria, including the newly defined Location- Information, Operator-Namespace, Operator-Name, Location-Type, Policy-Information attributes. A RADIUS Accounting Request message may also carry location specific attributes.+---------+ +---------+ +---------+ | Network | | Network | | AAA | | Access | | Access | | Server | | Client | | Server | | | +---------+ +---------+ +---------+ | | | | Authentication phase | | | begin | | |---------------------->| | | | | | | | | |RADIUS | | | Access-Request | | | + Location-Information | | | attributes | ||----------------------------->| | | | : : : : Multiple Protocol Exchanges to perform : : Authentication, Key Exchange and Authorization : : ...continued... : : : :| | RADIUS | | | Access-Accept | | | + Rule set Information | ||<-----------------------------| | Authentication | | | AcceptSuccess | | |<----------------------| | | | | | | RADIUS | | | Accounting RequestAccounting-Request | | | + Location-Information | | | attributes | ||----------------------------->| | | | Figure 1: Message Flow: Authentication/Authorization PhaseLocation Delivery 3.2 Mid-session Authorization The mid-session delivery method uses the Change of Authorization (COA) message as defined in . At anytime duringbased on out-of-band Agreements If no location information is provided by the sessionRADIUS client although it is required by the AAARADIUS server MAY send a COA message containing session identification attributesto compute an authorization decision then the access network. The COA message may instructRADIUS server challenges the access network to generate an Authorize-Only Access-Request (Access- Request with Service-Type set to "Authorize-Only")RADIUS client. This exchange is shown in which case the NAS MUST includeFigure 2. The Access-Challenge thereby provides a hint to Network Access Server regarding the type of location infromationinformation attributes that are desired. In the shown message flow these attributes are then provided in the subsequent Access-Request message. When receiving this Access-Request. Figure 2 showsAccess-Request message the approach graphically. +---------+authorization procedure at the RADIUS server might be based on a number of criteria, including the newly defined Location-Information and Operator-Name attributes. +---------+ +---------+ +---------+ | Network | | Network | | AAA | | Access | | Access | | Server | | Client | | Server | | | +---------+ +---------+ +---------+ | | | | Authentication phase | | | begin | | |---------------------->| | | | | | | RADIUS | | | Access-Request | | | + Challenge-Capable | | |----------------------------->| | | | | | RADIUS | | | Access-Challenge | | | + Rule set Information | | | + Requested-Info | | |<-----------------------------| | | | | | RADIUS | | | Access-Request | | | + Location-Information | | |----------------------------->| | | | : : : : Multiple Protocol Exchanges to perform : : Authentication, Key Exchange and Authorization : : ...continued... : : : : | | | | | RADIUS | | | Access-Accept | | | + Requested-Info | | |<-----------------------------| | Authentication | | | Success | | |<----------------------| | | | | | | RADIUS | | | Accounting-Request | | | + Location-Information | | |----------------------------->| | | | Figure 2: Location Delivery based on dynamic Request If the AAA server needs to obtain location information also in accounting messages then it needs to include a Requested-Info attribute to the Access-Accept to express that is desired. The Network Access Server SHOULD then include location information to the RADIUS accounting messages. 3.2. Mid-session Authorization The mid-session delivery method uses the Change of Authorization (COA) message as defined in . At anytime during the session the RADIUS server MAY send a COA message containing session identification attributes to the access network. The COA message MAY instruct the RADIUS client to generate an Authorize-Only Access- Request (Access-Request with Service-Type set to "Authorize-Only") in which case the RADIUS client MUST include location information in this Access-Request if it included location information is previous Access-Request messages. Figure 3 shows the approach graphically. +---------+ +---------+ | AAA | | AAA | | Client | | Server | | (NAS) | | | +---------+ +---------+ | | | COA + Service-Type "Authorize Only" | |<----------------------------------------------| | | | COA NAK + Service-Type "Authorize Only" | | + Error-Cause "Request Initiated" | |---------------------------------------------->| | | | Access-Request + Service-Type "Authorize Only"| | + Location Information attributesLocation-Information | | + Location Information policyPolicy-Rules | |---------------------------------------------->| | | | Access-Accept | |<----------------------------------------------| | | Figure 2: Message Flow:3: Mid-session Authorization Upon receiving the Authorize-Only message from the access network, the AAARADIUS server MUST respond with either an Access-Accept messageor an Access-Reject message. 4. Scenarios In the following subsections we describe two scenarios for use of location information. The location information may refer to the (visited) network or to the user. How the network obtains the user's location information is out of the scope of this document. There are two potential consumers of location information: the AAA server and location- basedlocation-based services. The privacy implications of these scenarios are described in Section 14. 4.113. 4.1. Scenario 1 - Use of Location Information in AAA The home network operator requires location information for authorization and billing purposes. The operator may deny service if location information is not available, or it may offer limited service. The NAS delivers location information to the home AAA server. The user'slocation of the AAA client and/or the end host is transferred from the NAS to the RADIUS server.server (based on a pre-established agreement or if the RADIUS server asks for it). The NAS and intermediaries (if any) are not allowed to use that information other than to forward it to the home network. The RADIUS server authenticates and authorizes the user requesting access to the network. If the user's location policies are available to the RADIUS server, the RADIUS server mustMUST deliver those policies in an Access Accept to the RADIUS client. This information mayMAY be needed if intermediaries or other elements want to act as Location Servers (see Section 4.2). If the NAS or intermediaries do not receive thesepolicies from the RADIUS server (or the end host itself) then they MUST NOT make any use of the location information other than forwarding it to the user's home network. Location Information may also be reported in accounting messages. Accounting messages are generated when the session starts, stops and periodically. Accounting messages may also be generated when the user roams during handoff. This information may be needed by the billing system to calculate the user's bill. For example, there may be different rates applied based on the location and there may be different tax rates applied based on the location. Unless otherwise specified by authorization rules, location information in the accounting stream MUST NOT be transmitted to third parties. The location information in the accounting stream MUST only be sent in the proxy chain to the home network (unless specified otherwise). 4.24.2. Scenario 2 - Use of Location Information for Other Services Location Servers are entities that receive the user's location information and transmit it to other entities. In this second scenario, Location Servers comprise also the NAS and the RADIUS server. The RADIUS servers are in the home network, in the visited network, or in broker networks. Unless explicitly authorized by the user's location policy, location information MUST NOT be transmitted to other parties outside the proxy chain between the NAS and the Home RADIUS server. Upon authentication and authorization, the home RADIUS server mustMUST transmit the ruleset (if available) in an Access-Accept. The RADIUS client, intermediate proxies are allowed to share location information if they received ruleset indicates that it is allowed. Note that the NAS is the source of all location information that is disseminated by RADIUS. The NAS tags the location information with the policy rules or a reference to the policy rules received in an Access-Accept. All location information in the accounting stream will also be tagged.5. OverviewDescription of Attributes Location information and ownership of the access network is conveyed in the following RADIUS attributes: Operator-Namespace, Operator- Name, Location-InformationOperator-Name and Location-Type.Location- Information. Furthermore, the Basic-Policy-Rules and the Extended-Policy-RulesExtended- Policy-Rules attributes are attached to the Location-Information attribute turning location information into a Location Object as defined in . 5.1 Operator-Namespace. 5.1. Operator-Name Attribute This attribute contains the description of anoperator namespace whichand the operator name. The operator name is combined with the Operator-Name attribute servesNamespace to uniquely identify the owner of an access network. The attributevalue of the Operator-Name is a non-NULL terminated string whose Lengthlength MUST NOT exceed 253 bytes. The attribute value uniquely identifies the operator name within the scope of the operator namespace This Namespace field within the Operator-Name attribute provides information about the operator namespace. This document defines threefour values for this attribute: GSM, CDMA, REALM and REALM.ITU. Additional namespaces require IANA registration and MUST be associated with an organization responsible for assigning and managing the operator namespace. GSM (0): The GSM operator namespace can be used to indicate operator names based on GSMA TADIG codes. The TADIG Working Group within the GSM Association is the authority responsible for issuing unique Operator- NameOperator-Name values for operators of this type. CDMA (1): The CDMA operator namespace can be used to indicate operator names based on the Home Network Identifier (HNI). The HNI is the concatenation of the 3-digit Mobile Country Code (MCC) and 3-digit Mobile Network Code (MNC). The IMSI Oversight Council (IOC) is the authority responsible for issuing unique Operator-Name values for operators of this type. REALM (2): The REALM operator namespace can be used to indicate operator names based on any registered domain name. Such names are required to be unique and the rights to use a given realm name are obtained coincident with acquiring the rights to use a particular Fully Qualified Domain Name (FQDN). 5.2 Operator-Name Attribute This attribute contains anITU (3): The ITU operator name which combined with the Operator-Namespace attribute servesnamespace can be used to uniquely identifies the owner of an access network. The attribute value is a non-NULL terminated string whose Length MUST NOT exceed 253 bytes. The attribute value uniquely identifies theindicate operator namenames based on ITU Carrier codes. The Telecommunication Standardization Bureau (TSB) within the scope ofITU-T is the operatorauthority responsible for the repository. Each national regulatory authority is responsible for issuing unique Operator-Name values for operators of this type. 5.35.2. Location-Information Attribute This document describes two formats for conveying location information: civic and geospatial location information. Section 184.108.40.206.1 defines the civic location information format. Section 220.127.116.11.2 defines the geospatial location information format. Additionally, the following fields provide more details about the transmitted location information. Entity: With the help of the 'Entity' field it is possible to differentiate whether the described Location Object refers to eitherthe user's client device (as estimated by the network) or to the location of the AAA client (such as NAS).client. Method: The 'Method' field describes the method for obtaining location information. GPS or manual configuration are possible methods for obtaining location information. The inclusion of this field should help the user's home network to deduce further information about the accuracy and to provide an easier translation into a Location Object for transmission to third party entities (e.g., using SIP). Note that the values for this field are taken from . 5.3.1. 5.2.1. Civic Location Information Civic location is a popular way to describe the location of an entity. Using anAn unstructured (as a text string) or a custom format for civiclocation format would limitlimits automatic processing capabilities are limited.by the RADIUS server. For this document, we taketherefore reuse the civic location format defined in . The civic location format includes a number of fields, including the country (expressed as a two-letter ISO 3166 code) and the administrative units A1 through A6 of  . This designation offers street-level precision. For completeness we include more detailed information from  with regard to the defined civic location elements: +----------------------+----------------------+---------------------++---------+-----------------------------------------+---------------+ | Label | Description | Example | +----------------------+----------------------+---------------------++---------+-----------------------------------------+---------------+ | country | The country is | US | | |identified by the | US | | | two-letter ISO 3166 | | | |code. | | | | | | | A1 | national | New York | | |subdivisions (state, | | | |region, province,| New York | | | province, prefecture) | | | | | | | A2 | county, parish, gun | King's County | | |(JP), district (IN) | King's County | | | | | | A3 | city, township, shi (JP) | New York | | | (JP) | | | || | | A4 | city division, | Manhattan | | |borough, city district, | Manhattan | | | district,ward, cho | | | |(JP) | | | | | | | A5 | neighborhood, block, chome (JP) | Morningside Heights| | | chome (JP)| Heights | | | | | | A6 | street, banchi and | Broadway | | |gou (JP) | Broadway | | | | | | AC | Additional code, JIS | 13203000003 | | |address code (JP) | 13203000003 | | | | | | PRD | Leading street direction | N, W | | | direction | | | || | | POD | Trailing street | SW | | |suffix | SW | | | | | | STS | Street suffix | Avenue, Street| | | | Street | | HNO| House number,| 123| | HNO | House number, numeric part only. | 123 | | | | | | HNS | House number suffix | A, 1/2 | | | | | | LMK | Landmark or vanity address | Low Library | | | address| | | LOC | Additional location information | Room 543 | | | information | | | || | | FLR | Floor | 5 | | | | | | NAM | Name (residence, | Joe's Barbershop | | |business or office | Joe's | | | occupant) | Barbershop | | | | | | PC | Postal code | 10027-0401 | +----------------------+----------------------+---------------------++---------+-----------------------------------------+---------------+ Table 1 More description of these civic location elements can be found in Section 3.4 of . These elements can be used to express further information about the location, language specific settings via the 'language' item and encoding information via the 'script' item. Section 1312 shows usage examples of this attribute. All attributes are optional and can appear in any order. The values are encoded using UTF-8 . 5.3.2The usage of the type of place element (CAtype 29). The values in this element defined for usage are definded with the location type registry . By using these location types it is possible to define more accurate location information. The type of place element (CAtype 29) may appear more than once. The content of this value will not be displayed to the user but rather used for authorization decisions. As such, internationalization support is not required. If multiple type of place elements are used then no specific semantic is associated regarding the order. Example values for location types are 'aircraft', 'airport', 'cafe', 'classroom', 'convention-center', 'restaurant', 'office' etc. 5.2.2. Geospatial Location Information This document reuses geospatial location information from  which defines latitude, longitude, and altitude,altitude with resolution indicators for each. The value in the Altitude field either indicates meters or floors (via the Altitude Type field). As a coordinate reference system Section 2.1 of  defines (via extensible mechanism using IANA registration) three values in the 'Datum' field: WGS 84, NAD 83 (with the associated vertical datum for the North American Vertical Datum of 1988), NAD 83 (with the associated vertical datum for the Mean Lower Low Water (MLLW). WGS 84 is used by the GPS system. During a protocol run it is possible toThe NAS might return Location-Information attributes which provide both types of location information elements. If only onecivic and geospatial location information element is provided theninformation. Per default civic location SHOULD be included in the request.added. 6. Basic- and Extended-Policy-Rule Attributes In some environments it is possible for the user to attach information about its privacy preferences.preferences available to the network. These preferences allow the visited network, intermediate RADIUS proxies and the home network to authorize the distribution of the user's location information. The home network will typically possess the user's authorization policies. Without the user providing authorization information two approaches are possible: o The user hides its locationidentity information from the access network and from intermediate networks using the appropriate network access authentication mechanism. Section 1413 discusses these issues in more details. o The access network attaches default authorization policies which indicates that intermediate networks and the home network should not distribute the location information to other entities. If the user is able to provide authorization policies to the NAS then these policies will be attached. Additionally, the home network might have authorization policies which control distribution of location information. These policies are sent from the RADIUS server to the RADIUS client. Users can dynamically change their policies using the authroization framework defined in  and .. With regard to authorization policies this document reuses work done in  and encodes it in an non-XML format. Two fields ('sighting time' and 'time-to-live') are additionally included in the Location- Information attribute to conform to the Geopriv Requirements ,, Section 2.7. Two RADIUS attributes are used for this purpose: Basic- Policy-Rule and Extended-Policy-Rule attribute. The Basic-Policy- Rule attribute contains a fixed set of privacy relevant fields whereas the Extended-Policy-Rule attribute contains a reference to a more extensive authorization rule set. 7. Location-TypeRequested-Info Attribute This document usesThe Requested-Info attribute allows the RADIUS server to indicate whether it needs civic and/or geospatial location information of the NAS or the end host (i.e., the entities that are indicated in the Entity field of the Location-Information attribute). 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 AAA client and the AAA server have agreed out-of-band to mandate the transfer of location information for every network access authentication request then the issues listed below are not applicable. o The RADIUS server requires location information for computing the authorization decision. If the RADIUS client does not provide location information with the Access-Request message then the Requested-Info attribute is attached to the Access-Challenge to indicate what is required. Two cases can be differentiated: 1. If the RADIUS client sends the requested information then the RADIUS server can process the location-based attributes. 2. If the RADIUS server does not receive the requested information in response to the Access-Challenge (including the Requested-Info attribute) then the values defined inRADIUS server responds with an Access-Reject with an Error-Cause attribute (including the location type registry . By using these location types it is possible to define more accurate location information."Location-Info-Required" error value). Note that multiple values canan Access- Reject message SHOULD only be specified in this attribute. 8. Capability Attribute The capability attribute allowssent if the RADIUS client to indicate whether civic and/or geospatialserver MUST use location information can be provided tofor returning a positive access control decision. o If the RADIUS server. This is useful to avoid sendingserver would like location information with every request if no further out-of-band arrangements are made with regard toin the transport of location information. The AAA server usesAccounting-Request message but does not require it for computing an authorization decision then an Access-Accept MUST include a Required-Info attribute. This is typically the capability attributecase when location information is used for inclusion to indicate thatthe AAAuser's bill only.The RADIUS client has to provide civic and/or geospatialSHOULD attach location information as part of this particular protocol exchange.to the Accounting-Request (unless authorization policies dictate something different), if it is available. If the AAARADIUS server does not send a capabilityRequested-Info attribute then the AAARADIUS client MUST NOT returnattach location information.information to messages to the RADIUS server The user's authorization policies MUST be consulted by the AAARADIUS server before requesting location information delivery from the AAARADIUS client. If the AAA server encounters that the AAA client does not support the desired location information it might respond with an Access-Reject with the corresponding error cause attribute (with the Location-Info-Required error code).Figure 34 shows a simple protocol exchange where the AAA clientRADIUS server indicates that it is ablethe desire to provideobtain location information, namely civic and geospatiallocation information andof the AAAuser, to grant access. Since the Requested-Info attribute is attached to the Access-Challenge the RADIUS server indicates that that civiclocation information is desired for this particular exchange.required for computing an authorization decision. +---------+ +---------+ | AAARADIUS | | AAARADIUS | | Client | | Server | | | | |+---------+ +---------+ | | | | | RADIUS | | Access-Request | | + Capability | | ('CIVIC_LOCATION', | | 'GEO_LOCATION')+Challenge-Capable | |----------------------------->| | | | RADIUS | | Access-Challenge | | + CapabilityRequested-Info | | ('CIVIC_LOCATION')('CIVIC_LOCATION', | | 'USERS_LOCATION') | |<-----------------------------| | | | RADIUS | | Access-Request | | + Location-Information | | (civic-location) | |----------------------------->| | | | .... | Figure 3: Capability Exchange Example 9.4: RADIUS server requesting location information 8. Diameter RADIUS Interoperability In deployments where RADIUS clients communicate with DIAMETERDiameter servers or DIAMETERDiameter clients communicate with RADIUS servers then a translation agent will be deployed and operate. The NASREQ specification  provides translation services. Furthermore, the RADIUS attributes specified in this document are also applicable for deployments where DIAMETERDiameter clients talk with DIAMETERDiameter servers. DIAMETERDiameter AVP Code numbers for corresponding RADIUS attributes are allocated as specified in DIAMETERDiameter Base Protocolprotocol specification Section 4.1 . 10.9. Attributes This section defines the Operator-Namespace AVP,Operator-Name AVP, Location-Information AVP,attribute, Location- Information attribute, Basic Policy Rules AVP,attribute, Extended Policy Rules AVP, Location-Type AVPattribute, and the Capability AVP. 10.1 Operator-Namespace Attribute Operator-Namespaceattribute. 9.1. Operator-Name Attribute The Operator-Name attribute SHOULD be sent in Access-Request, and Accounting-Request records where the Acc-Status-Type is set to Start, Interim, or Stop. A summary of the Operator-Namespace AttributeOperator-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 | Operator-NamespaceNamespace | Operator-Name ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Operator-Name ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: To Be Assigned by IANA - Operator-NamespaceOperator-Name Length: >= 3 Bytes Operator-Namespace:Namespace: The textvalue within this field contains an Access Networkthe Operator Type.Namespace identifier. Example: REALM 10.2 Operator-Name Attribute Operator-Name Attribute SHOULD be sent in Access-Request, and Accounting-Request records where the Acc-Status-Type is set to Start, Interim, or Stop. A summary of the Operator-Name Attribute is shown below. 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 01 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Operator-Name ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: To Be Assigned by IANA - Operator-Name Length: >= 3 Bytesfor CDMA Operator-Name: The text field of variable length contains an Access Network Operator Name. This field is a RADIUS base data type of Text. Example: anyisp.com 10.39.2. Location-Information Attribute Location-Information attribute SHOULD be sent in Access-Request, and Accounting-Request records where the Acc-Status-Type is set to Start, Interim or Stop if available. The Location-Information Attribute has two variations depending on civic or geospatial location information. The format is shown below. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Code | Entity | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sighting Time ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sighting Time | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Time-to-Live ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Time-to-Live | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Method | Location-Info ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type (8 bits): To Be Assigned by IANA - Location-Information Length (8 bits): >= 3 Bytes Code (8 bits): Describes the location format that is carried in this attribute: (0) describes civic location information (1) describes geospatial location information Entity (8 bits): Describes which location this attribute refers to: (0) describes the location of the user's client device (1) describes the location of the AAA client Sighting Time (64 bits): NTP timestamp for the 'sighting time' field. Time-to-Live (64 bits): NTP timestamp for the 'time-to-live' field. Method (8 bits): Describes the way that the location information was derived or discovered. The following values are defined: (0) Global Positioning System (GPS) (1) GPS with assistance (A-GPS) (2) Manual configured information (3) Provided by DHCP (4) Triangulation: triangulated from time-of-arrival, signal strength or similar measurements (5) Cell: location of the cellular radio antenna (6) IEEE 802.11 WLAN access point Location-Info (variable): Contains either civic or geospatial location information attributes. The following two fields need some explanation: sighting time: This field indicates when the Location Information was accurate. The data type of this field is a string and the format is a 64 bit NTP timestamp .. time-to-live: This field gives a hint until when location information should be considered current. Note that the time-to-live field is different than retention-expires, which indicates the time the recipient is no longer permitted to possess the location information and its encapsulating Location Object. The data type of this field is a string and the format is a 64 bit NTP timestamp .. For civic location information the Location-Info field in the above structure is defined as followed: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Countrycode | Civic address elements ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Countrycode (16 bits): Two-letter ISO 3166 country code in capital ASCII letters. Civic address elements (variable): The text field contains location information element. The format of the civic address elements is described in Section 3.3 of  with a TLV pair (whereby the Type and Length fields are one octet long). An example is given in Section 13.12. For geospatial location information the Location-Info field is defined as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LaRes | Latitude + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Latitude | LoRes | Longitude + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Longitude | AT | AltRes | Altitude + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Altitude | Datum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ LaRes (6 bits): Latitude resolution Latitude (34 bits) LoRes (6 bits): Longitude resolution. Longitude (34 bits) Altitude (30 bits) AltRes (6 bits): Altitude resolution AT (4 bits): Altitude Type for altitude. The following codes are defined: (1) Meters (2) Floors Datum (8 bits): Coordinate reference system The following codes for the this field are defined: (1) WGS 84 (2) NAD 83 (with the associated vertical datum for the North American Vertical Datum of 1988) (3) NAD 83 (with the associated vertical datum for the Mean Lower Low Water (MLLW)) The length of the Location-Information Attribute MUST NOT exceed 253 octets. The length of the geospatial location information format is fixed with 16 bytes plus a four byte header. The 'Datum' field contains an identifier for the coordinate system used to interpret the values of Latitude, Longitude and Altitude. The field with value (2) and the value (3) both represent the NAD 83 coordinate reference system but they differ from each other with regard to their vertical datum representation as briefly noted in Section 18.104.22.168.2 and described in more detail in . 10.4. 9.3. Basic Policy Rules Attribute The Basic-Policy-Rules attribute MUST be sent in Access-Accept, Access-Challenge, Access-Request, Access-Reject and Accounting- Request messages if location information is transmitted with this exchange. If authorization policy rules are available to the RADIUS client then the Access-Request MUST carry the Basic-Policy-Rules attribute to to the RADIUS server. A summary of the Basic-Policy-Rules attribute is shown below. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length |R| Flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Retention Expires ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Retention Expires | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Note Well ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type : To Be Assigned by IANA - Basic-Policy-Rules Length: > 3 Bytes Flag (16 bits): Only the first bit (R) is defined an corresponds to the retransmission-allowed field. All other bits are reserved. Retention Expires (64 bits): NTP timestamp for the 'retention-expires' field. Note Well (variable): This field contains a URI which points to human readable privacy instructions. This document reuses fields of the 'usage-rules' element, described in .. These fields have the following meaning: retransmission-allowed: When the value of this element is '0', then the recipient of this Location Object is not permitted to share the enclosed location information, or the object as a whole, with other parties. The value of '1' allows to share the location information with other parties by considering the extended policy rules. retention-expires: This field specifies an absolute date at which time the Recipient is no longer permitted to possess the location information. The data type of this field is a string and the format is a 64 bit NTP timestamp .. note-well: This field contains a URI which points to human readable privacy instructions. This field is useful when location information is distributed to third party entities, which can include humans in a location based service. RADIUS entities are not supposed to process this field. Whenever a Location Object leaves the AAA system the URI in the note-well attribute MUST be expanded to the human readable text. For example, when the Location Object is transferred to a SIP based environment then the human readable text is placed in the text is put into the 'note-well' attribute inside the 'usage- rules' element inside the PIDF-LO document (see ). 10.5). 9.4. Extended Policy Rules Attribute The Extended-Policy-Rules attribute SHOULD be sent in Access-Accept, Access-Challenge, Access-and Access-Reject messages if location information is transmitted with this exchange. If authorization policy rules are available to the RADIUS client then the Access- Request MUST carry the Basic-Policy-Rules attribute to to the RADIUS server. Ruleset reference field of this attribute is of variable length. It contains a URI that indicates where a richer ruleset is available. The full ruleset SHOULD be fetched using Transport Layer Security (TLS). As a deviation from  this field only contains a reference and does not carry an attached rule set. This modification is motivated by the size limitations imposed by RADIUS. A summary of the Extended-Policy-Rules attribute is shown below. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Ruleset reference ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type : To Be Assigned by IANA - Extended-Policy-Rules Length: > 3 Bytes Ruleset reference: The text field contains a URI which points to policy rules. 10.6 Location-Type Attribute Location-Type9.5. Challenge-Capable Attribute SHOULD be sent in Access-Request,The Challenge-Capable attribute allows a NAS (or client function of a proxy server) to indicate support for processing general purpose Access-Challenge messages from the RADIUS server, beyond those specified for support of the authentication methods of textual challenge-response, CHAP or EAP. This mechanism allows the RADIUS server to request additional information from the RADIUS client prior to making an authentication and Accounting-Request records whereauthorization decision. The Challenge-Capable attribute MUST appear in Access-Request Messages, if the Acc-Status-Type is setNAS supports this feature, as a hint to Start, Interim, or Stop if available. A summary ofthe Location-Type Attribute is shown below.RADIUS Server. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Loc-TypeValue | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type (8 bits): To Be Assigned by IANA - Location-NameChallenge-Capable Attribute Length (8 bits): = 4 Bytes Loc-TypeValue (16 bits): The content of this field corresponds to the integer codes for access network location type. These integer codes for the location type canMUST be found in Section 7. 10.7 Capabilityset to 0. 9.6. Requested-Info Attribute The CapabilityRequested-Info attribute SHOULDMUST be sent by the RADIUS server if it wants the RADIUS client to return civic and/or geospatial information. This Requested-Info attribute MAY appear in the Access-Request andAccess- Accept or in the Access-Challenge messages. A summary of the Capabilityattribute 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 | Capabilities ...Requested-Info | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Requested-Info | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: To Be Assigned by IANA - Operator-NameRequested-Info Attribute Length: >= 36 Bytes Capabilities (128Requested-Info (48 bits): This text field contains a numerical value that encodes the corresponding capabilities.requested information attributes. Each value represents a bit position. Currently the following capabilities are specified: CapabilityName: CIVIC_LOCATION Description: In the directionThe RADIUS server uses this attribute to request information from the AAARADIUS client to be returned. The numerical value representing CIVIC_LOCATION requires the AAARADIUS client to attach civic location attributes. Numerical Value: A numerical value of this attribute is '0'. Name: GEO_LOCATION Description: The RADIUS server uses this capability refersattribute to request information from the RADIUS client to be returned. The numerical value representing GEO_LOCATION requires the abilityRADIUS client to attach geospatial location attributes. Numerical Value: A numerical value of this attribute is '2'. Name: USERS_LOCATION Description: The numberical value representing USERS_LOCATION indicates that the AAA client must sent civica Location-Information attribute that contains location information. Ininformation with the Entity attribute expressing the value of zero (0). 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 attribute is '4'. Name: NAS_LOCATION Description: The numberical value representing NAS_LOCATION indicates that the AAA client must sent a Location-Information attribute that contains location information with the Entity attribute expressing the direction fromvalue of one (1). A value of one indicates that the AAA server tolocation information in the AAA client this capabilityLocation-Information attribute refers to the desire of theAAA server to receive civic location.client. Numerical Value: A numerical value of this attribute is '0'. Capability Name: GEO_LOCATION Description: In the direction from'8'. If neither the AAA client toNAS_LOCATION nor the AAA server this capability refers toUSERS_LOCATION bit is set then per-default the ability to sent geospatiallocation information. Inof the direction fromuser's client device MUST be returned. If neither the AAA server toCIVIC_LOCATION nor the AAA client this capabilityGEO_LOCATION bit is set then per-default geospatial location information MUST be returned. The value of NAS_LOCATION and USERS_LOCATION refers to the desirelocation requested via CIVIC_LOCATION and/or via GEO_LOCATION. As an example, if the bits for NAS_LOCATION, USERS_LOCATION and GEO_LOCATION are set then location information of the AAA server to receiveclient and the users' client device are returned in a geospatial location. Numerical Value: A numerical value of this attribute is '2'. 11.location format. 10. Table of Attributes The following table provides a guide which attributes may be found in which RADIUS messages, and in what quantity. Request Accept Reject Challenge Accounting # Attribute Request 0-1 0 0 0 0-1 TBD Operator-Name 0-1 0 0 0 0-1 TBD Operator-Namespace0+ 0 0 0 0+ TBD Location-Information 0-1 0-1 0-1 0-1 0-1 TBD Basic-Policy-Rules 0-1 0-1 0-1 0-1 0-1 TBD Extended-Policy-Rules 0-1 00 0-1 0 0-1 0-1 TBD Location-TypeRequested-Info 0-1 0 0 0-10 0 TBD CapabilityChallenge-Capable The Location-Information attribute may appear more than once. This is useful if the size of one Location-Information attribute exceeds the maximum size of an AVP.attribute. This might happen in case of civic location information that has a variable number of fields. The individual fields used for representing civic location information inside the Location-Information AVPattribute (see Section 22.214.171.124.1) MUST NOT appear more than once. For example, it is not allowed to have a CAtype of 3 (indicating the name of the city) to appear more than once. The next table shows the occurrence of the error-cause attribute. Request Accept Reject Challenge Accounting # Attribute Request 0 0 0-1 0-1 0-10 0 TBD Location-Info-Required 0 0 0-1 0 0 101 Error-Cause 12.11. Matching with Geopriv Requirements This section compares the Geopriv requirements described in  and the approach of distributing Location Objects with RADIUS. The main usage scenario aimed for Location Object transport in RADIUS assumes that the Location Server and the Location Recipient are co- located at a single entity with regard to location based network access authorization, taxation and billing. In Section 12.111.1 and Section 12.211.2 we discuss privacy implications when RADIUS is not used according to these usage scenario. In Section 12.311.3 Geopriv requirements are matched against these two scenarios. 12.111.1. Distribution of Location Information at the User's Home Network This section focuses on location information transport from the local AAA server (acting as the Location Generator) to the home AAA server (acting as the Location Server). To use a more generic scenario we assume that the visited AAA and the home AAA server belong to different administrative domains. The Location Recipient obtains location information about a particular Target via protocols specified outside the scope this document (e.g., SIP, HTTP or an API). Please note that the main usage scenario defined in this document assumes that the Location Server and the Location Recipient are co- located into a single entity with regard to location based network access authorization, taxation and billing. The subsequent figure shows the interacting entities graphically. visited network | home network | | +----------+ | | Rule | | | Holder | | | | | +----+-----+ | | | rule|interface | V +----------+ | +----------+ +----------+ |Location | publication | Location | notification |Location | |Generator |<------------->| Server |<------------->|Recipient | | | interface | | interface | | +----------+ | +----------+ +----------+ | Local AAA RADIUS Home AAA SIP/HTTP/API/etc. Server | Server | Figure 16: Location Server at the Home Network The term 'Rule Holder' in Figure 16 denotes the entity which creates the authorization ruleset. 12.211.2. Distribution of Location Information at the Visited Network This section describes a scenario where Location Information is distributed by the visited network. In order for this scenario to be applicable the following two assumptions must hold: o The visited network deploys a Location Server and wants to distribute Location Objects of a user o The visited network is able to learn the user's identity The visited network provides location information to a Location Recipient (e.g., via SIP or HTTP). During the network access authentication procedure the visited network is able to retrieve the user's authorization policies from the home AAA server. This should ensure that the visited network acts according to the user's policies. The subsequent figure shows the interacting entities graphically. The transport of the Location Object is not shown in this figure since this aspect is already covered in the previous paragraph. visited network | home network | +----------+ | |Location | | |Recipient | | | | | +----------+ | ^ | +----------+ | | | Rule | | | | Holder | notification | | | interface | +----+-----+ | | | | | rule|interface v | V +----------+ | +----------+ |Location | Rule Transport| Home AAA | |Generator |<------------->| Server | |& Server | RADIUS | | +----------+ | +----------+ | Figure 17: Location Server at the Visited Network 12.311.3. Requirements matching Section 7.1 of  details the requirements of a "Location Object". There are: Req. 1. (Location Object generalities): * Regarding requirement 1.1, the Location Object has to be understood by the RADIUS server (and possibly a Diameter server in case of interworking between the two) as defined in this document. Due to the encoding of the Location Object it is possible to convert it to the format used in GMLv3 .. The same civic location information format is used in PIDF-LO  and this document. * Regarding requirement 1.2, some fields of the Location Object defined in this document are optional. See Section 126.96.36.199.1 as an example. * Regarding requirement 1.3, the inclusion of the Location-Type attribute whichtype of place item (CAtype 29) gives a further classification of the location. This attribute can be seen as an extension. * Regarding requirement 1.4, the Location Object is extensible in the same fashion as RADIUS is extensible. * Regarding requirement 1.5, the Location Object is useful for both receiving and sending location information as described in this document. * Regarding requirement 1.6, the Location Object contains both location information and privacy rules. Location information is described in Section 5.35.2 and the corresponding privacy rules are detailed in Section 10.49.3 and in Section 10.5.9.4. * Regarding requirement 1.7, the Location Object is usable in a variety of protocols. The format of the object is reused from other documents as detailed in the respective sections (see Section 5.3,5.2, Section 10.49.3 and in Section 10.5).9.4). * Regarding requirement 1.8, the encoding of the Location Object has an emphasis on a lightweight encoding format. As such it is useable on constrained devices. Req. 2. (Location Object fields): * Regarding requirement 2.1, the Target Identifier is carried within the network access authentication protocol (e.g., within the EAP-Identity Response when EAP is used and/or within the EAP method itself). As described in Section 1413 it has a number of advantages if this identifier is not carried in clear text. This is possible with certain EAP methods whereby the identity in the EAP-Identity Response only contains information relevant for routing the response to the user's home network. The user identity is protected by the authentication and key exchange protocol. * Regarding requirement 2.2, the Location Recipient is in the main scenario the home AAA server. For a scenario where the Location Recipient is obtaining Location Information from the Location Server via HTTP or SIP the respective mechanisms defined in these protocols are used to identify the recipient. The Location Generator cannot, a priori, know the recipients if they are not defined in this protocol. * Regarding requirement 2.3, the credentials of the Location Recipient are known to the RADIUS entities based on the security mechanisms defined in the RADIUS protocol itself. Section 1514 describes these security mechanisms offered by the RADIUS protocol. The same is true for requirement 2.4. * Regarding requirement 2.5, Section 5.35.2 describes the content of the Location Field. Motion and direction vectors as listed in requirement 2.6 are not provided as attributes. It is, however, possible to deduce the motion and direction of an entity via the Mid-session Delivery mechanism as shown in Figure 2.3. * Regarding requirement 2.6, this document only describes one Location Data Type for civic and for geospatial location information, respectively. No negotiation needs to take place. * Regarding requirement 2.7, timing information is provided with 'sighting time' and 'time-to-live' field defined in Section 10.4.9.3. * Regarding requirement 2.8, a reference to an external (more detailed ruleset) is provided with the Section 10.59.4 attribute. * Regarding requirement 2.9, security headers and trailers are provided as part of the RADIUS protocol or even as part of IPsec. * Regarding requirement 2.10, a version number in RADIUS is provided with the IANA registration of the attributes. New attributes are assigned a new IANA number. Req. 3. (Location Data Types): * Regarding requirement 3.1, this document defines two Location Data Types as described in Section 188.8.131.52. * With the support of civic and geospatial location information support requirement 3.2 is fulfilled. * Regarding requirement 3.3, the geospatial location information as defined in this document only refers to absolute coordinates. However, the granularity of the location information can be reduced with the help of the AltRes, LoRes, LaRes fields described in the Location-Information attribute (see Section 10.3).9.2). * Regarding requirement 3.4, further Location Data Types can be added via new coordinate reference systems (CRSs) (see Datum field in the Location-Information attribute of Section 5.3),5.2), extensions to existing fields (e.g., new location types as shown in Section 7)or via additional attributes. Section 7.2 of  details the requirements of a "Using Protocol". These requirements are listed below: Req. 4.: The using protocol has to obey the privacy and security instructions coded in the Location Object and in the corresponding Rules regarding the transmission and storage of the LO. This document requires, that RADIUS entities sending or receiving location MUST obey such instructions. Req. 5.: The using protocol will typically facilitate that the keys associated with the credentials are transported to the respective parties, that is, key establishment is the responsibility of the using protocol. Section 1514 specifies how security mechanisms are used in RADIUS and how they can be reused to provide security protection for the Location Object. Additionally, the privacy considerations (see Section 14)13) are also relevant for this requirement. Req. 6. (Single Message Transfer): In particular, for tracking of small target devices, the design should allow a single message/ packet transmission of location as a complete transaction. The encoding of the Location Object is specifically tailored towards the inclusion into a single message that even respects the (Path) MTU size. The concept of a transaction is not immediately applicable to RADIUS. Section 7.3 of  details the requirements of a "Rule based Location Data Transfer". These requirements are listed below: Req. 7. (LS Rules): With the scenario shown in Figure 16 the decision of a Location Server to provide a Location Recipient access to location information is based on Rule Maker-defined Privacy Rules which are stored at the home network or are accessible for the home network. With regard to the scenario shown in Figure 17 the Rule Maker-defined Privacy Rules are sent from the home network to the visited network as part of the Policy-Information attribute (see Section 10.4,9.3, Section 10.59.4 and Section 1413 for more details). Req. 8. (LG Rules): For mid-session delivery it is possible to enforce the user's privacy rules for the transfer of the Location Object. For the initial transmission of a Location Object the user would have to use network access authentication methods which provide user identity confidentiality which would render the Location Object completely useless for the visited network. For the scenario shown in Figure 16 the visited network is already in possession of the users location information prior to the authentication and authorization of the user. A correlation between the location and the user identity might, however, still not be possible for the visited network (as explained in Section 14).13). The visited network MUST evaluate ruleset provided by the home AAA server as soon as possible. Req. 9. (Viewer Rules): The Rule Maker might define (via mechanisms outside the scope of this document) which policy rules are disclosed to other entities. Req. 10. (Full Rule language): Geopriv has defined a rule language capable of expressing a wide range of privacy rules which is applicable in the area of the distribution of Location Objects. A basic ruleset is provided with the Basic-Policy-Rules attribute Section 10.4.9.3. A reference to the extended ruleset is carried in Section 10.5.9.4. The format of these rules are described in  and .. Req. 11. (Limited Rule language): A limited (or basic) ruleset is provided by the Policy-Information attribute Section 10.49.3 (and as introduced with PIDF-LO ).). Section 7.4 of  details the requirements of a "Location Object Privacy and Security". These requirements are listed below: Req. 12 (Identity Protection): Support for unlinkable pseudonyms is provided by the usage of a corresponding authentication and key exchange protocol. Such protocols are available, for example, with the support of EAP as network access authentication methods. Some EAP methods support passive user identity confidentiality whereas others even support active user identity confidentiality. This issue is further discussed in Section 15.14. The importance for user identity confidentiality and identity protection has already been recognized (see for example a document on 'EAP Method Requirements for Wireless LANs' ).). Req. 13. (Credential Requirements): As described in Section 1514 RADIUS signaling messages can be protected with IPsec. This allows a number of authentication and key exchange protocols to be used as part of IKE, IKEv2 or KINK. Req. 14. (Security Features): Geopriv defines a few security requirements for the protection of Location Objects such as mutual end-point authentication, data object integrity, data object confidentiality and replay protection. As described in Section 1514 these requirements are fulfilled with the usage of IPsec if the mutual authentication refers to the RADIUS entities (acting as various Geopriv entities) which directly communicate with each other. Req. 15. (Minimal Crypto): A minimum of security mechanisms are mandated by the usage of RADIUS. Communication security for Location Objects between AAA infrastructure elements is provided by the RADIUS protocol (including IPsec and its dynamic key management framework) rather than on relying on object security via S/SIME (which is not available with RADIUS). 13.12. Example This section provides an example for a civic location information format within the Location-Information attribute. The size of the geo-spatial location information object is fixed and well-described examples can be found in the Appendix of .. Due to the size limitations of the RADIUS attributes we give a more detailed example borrowed from Section 4 of . +-------------+-----------+-------------------+ | Type | Length | Value | +-------------+-----------+-------------------+ | Type | 8 bits | TBD | | Length | 8 bits | --total length-- | | Code | 16 bits | 1 | | Precision | 8 bits | 2 | | Countrycode | 16 bits | DE | | CAtype | 8 bits | 1 | | CAlength | 8 bits | 7 | | CAvalue | 7 bytes | Bavaria | | CAtype | 8 bits | 3 | | CAlength | 8 bits | 6 | | CAvalue | 6 byte | Munich | | CAtype | 8 bits | 6 | | CAlength | 8 bits | 11 | | CAvalue | 11 bytes | Marienplatz | | CAtype | 8 bits | 19 | | CAlength | 8 bits | 1 | | CAvalue | 1 byte | 8 | | CAtype | 8 bits | 24 | | CAlength | 8 bits | 5 | | CAvalue | 5 bytes | 80331 | +-------------+-----------+-------------------+ The Length element provides the length of the entire payload minus the length of the initial 'Type', the 'Length' and the 'Code' attribute. The 'Entity' field has a value of '2' which refers to the location of the user's client. The 'CountryCode' field is set to 'DE'. Note that the subsequent attributes are in Type-Length-Value format. Type '1' indicates the region of 'Bavaria', '3' refers to the city 'Munich', '6' to the street 'Marienplatz', the house number '8' is indicated by the type '19' and the zip code of '80331' is of type '24'. The length of the elements need to consider the fact that all CAvalue elements are UTF-8 encoded. The following example illustrates a civic address in Japan. +-------------+-----------+-------------------+ | Type | Length | Value | +-------------+-----------+-------------------+ | Type | 8 bits | TBD | | Length | 8 bits | --total length-- | | Code | 16 bits | 1 | | Precision | 8 bits | 2 | | Countrycode | 16 bits | JP | | CAtype | 8 bits | 1 | | CAlength | 8 bits | 5 | | CAvalue | 7 bytes | Tokyo | | CAtype | 8 bits | 3 | | CAlength | 8 bits | 13 | | CAvalue | 6 byte | Musashino-shi | | CAtype | 8 bits | 5 | | CAlength | 8 bits | 7 | | CAvalue | 11 bytes | 3-chome | | CAtype | 8 bits | 30 | | CAlength | 8 bits | 8 | | CAvalue | 1 byte | 180-8585 | | CAtype | 8 bits | 32 | | CAlength | 8 bits | 11 | | CAvalue | 5 bytes | 13203000003 | +-------------+-----------+-------------------+ Please note that the CAtype 32 ("additional code" item) provides an additional, country-specific code identifying the location, such as the Japan Industry Standard (JIS) address code. 14.13. Privacy Considerations This section discusses privacy implications for the distribution of location information within RADIUS. In many cases the location information of the network also reveals the current location of the user with a certain degree of precision depending on the mechanism used, the positioning system, update frequency, where the location was generated, size of the network and other mechanisms (such as movement traces or interpolation). Two entities might act as Location Servers as shown in Section 4, in Figure 16 and in Figure 17: 14.113.1. Entity in the visited network In this scenario it is difficult to obtain authorization policies from the end host (or user) immediately when the user attaches to the network. In this case we have to assume that the visited network does not allow unrestricted distribution of location information to other than the intended recipients (e.g., to third party entities). The visited network MUST behave according to the following guidelines: o Per default only the home network is allowed to receive location information. The visited network MUST NOT distribute location information to third parties without seeing the user's privacy rule se. o If the home network provides the Basic-Policy-Rules attribute either as part of the Access-Accept, the Access-Reject or the Access-Challenge message then the visited network MUST follow the guidance given with these rules. o If the home network provides the Extended-Policy-Rules attributes either as part of the Access-Accept, the Access-Reject or the Access-Challenge message then the visited network MUST fetch the full ruleset at the indicated URL and MUST follow the guidance given with these rules. o If the RADIUS client in the visited network learns the basic rule set or a reference to the extended rule set by means outside the RADIUS protocol (e.g., provided by the end host) then it MUST include the Basic-Policy-Rules and the Extended-Policy-Rules attribute in the Access-Request message towards the home AAA server. Furthermore, the visited network MUST evaluate these rules prior to the transmission of location information either to the home network or a third party. The visited network MUST follow the guidance given with these rules. o If the RADIUS client in the visited network receives the Basic- Policy-Rules attribute with Access-Accept or the Access-Challenge message then the Basic-Policy-Rules MUST be attach in subsequent RADIUS messages which contain the Location-Information attribute (such as interim accounting messages). o If the RADIUS client in the visited network receives the Extended- Policy-Rules attribute with Access-Accept or the Access-Challenge message then the Basic-Policy-Rules attribute MUST be attach in subsequent RADIUS messages which contain the Location-Information attribute (such as interim accounting messages). 14.213.2. Entity in the home network The AAA server in the home network might be an ideal place for storing authorization policies. The user typically has a contractual relationship with his home network and hence the trust relationship between them is stronger. Once the infrastructure is deployed and useful applications are available there might be a strong desire to use location information for other purposes as well (such as location aware applications). Authorization policy rules described in  and in  are tailored for this environment. These policies might be useful for limiting further distribution of the user's location to other location based services. The home AAA server (or a similar entity) thereby acts as a location server for access to location services. The home network MUST behave according to the following guidelines: o As a default policy the home network MUST NOT distribute the user's location information to third party entities. o If a user provides basic authorization policies then these rules MUST be returned to the visited network in the Access-Accept, the Access-Reject or the Access-Challenge message. o If a user provides basic authorization policies then these rules MUST be returned to the visited network in the Access-Accept, the Access-Reject or the Access-Challenge message. o If a user provides extended authorization policies then they MUST be accessible for the visited networking using a reference to these rule set. The Extended-Policy-Rules attribute MUST include the reference and they MUST be sent to the visited network in the Access-Accept, the Access-Reject or the Access-Challenge message. o The home network MUST follow the user provided rule set for both local storage and for further distribution. With regard to the usage of these rules the home network MUST ensure that the users preferences are taken care of within the given boundaries (such as legal regulations or operational considerations). For example, a user might not want the home network to store information about its location information beyond a indicated time frame. However, a user might on the other hand want to ensure that disputes concerning the billed amount can be resolved. location information might help to resolve the dispute. The user might, for example, be able to show that he has never been at the indicated place. o If the policy rules provided by the user indicate that location information must not be distributed at all then the home network MUST provide the Basic-Policy-Rules to the RADIUS entity in the visited network via an Access-Accept, the Access-Reject and the Access-Challenge message. The RADIUS server in the user's home network would set the 'Retention-Expires' and the 'Retransmission- allowed' field to the user indicated value. For the envisioned usage scenarios, the identity of the user and his device is tightly coupled to the transfer of location information. If the identity can be determined by the visited network or AAA brokers, then it is possible to correlate location information with a particular user. As such, it allows the visited network and brokers to learn movement patterns of users. The identity of the user can "leak" to the visited network or AAA brokers in a number of ways: o The user's device may employ a fixed MAC address, or base its IP address on such an address. This enables the correlation of the particular device to its different locations. Techniques exist to avoid the use of an IP address that is based on MAC address .. Some link layers make it possible to avoid MAC addresses or change them dynamically. o Network access authentication procedures such as PPP CHAP  or EAP  may reveal the user's identity as a part of the authentication procedure. Techniques exist to avoid this problem in EAP, for instance by employing private Network Access Identifiers (NAIs) in the EAP Identity Response message  and by method-specific private identity exchange in the EAP method (e.g., ,, )., ). Support for identity privacy within CHAP is not available. o AAA protocols may return information from the home network to the visited in a manner that makes it possible to either identify the user or at least correlate his session with other sessions, such as the use of static data in a Class attribute  or in some accounting attribute usage scenarios .. o Mobility mechanisms may reveal some permanent identifier (such as a home address) in cleartext in the packets relating to mobility signaling. o Application protocols may reveal other permanent identifiers. Note that to prevent the correlation of identities with location information it is necessary to prevent leakage of identity information from all sources, not just one. Unfortunately, most users are not educated about the importance of identity confidentiality and there is a lack of support for it in many protocols. This problem is made worse by the fact that the users may be unable to choose particular protocols, as the choice is often dictated by the type of network they wish to access, the kind of equipment they have, or the type of authentication method they are using. A scenario where the user is attached to the home network is, from a privacy point of view, simpler than a scenario where a user roams into a visited network since the NAS and the home AAA are in the same administrative domain. No direct relationship between the visited and the home network operator may be available and some AAA brokers need to be consulted. With subscription-based network access as used today the user has a contractual relationship with the home network provider which could allow higher privacy considerations to be applied (including policy rules stored at the home network itself for the purpose of restricting further distribution). In many cases it is necessary to secure the transport of location information along the RADIUS infrastructure. Mechanisms to achieve this functionality are discussed in Section 15. 15.14. 14. Security Considerations Requirements for the protection of a Location Object are defined in :: Mutual end-point authentication, data object integrity, data object confidentiality and replay protection. The distribution of location information can be restricted with the help of authorization policies. Basic authorization policies are attached to the location information itself, in the same fashion as described in .. It is possible that the user was already able to transfer some authorization policies to the access network to restrict the distribution of location information. This is, however, rather unlikely in case of roaming users. Hence, it will be primarily the NAS creating the Location Object which also sets the authorization policies. If no authorization information is provided by the user then the visited network MUST set the authorization policies to only allow the home AAA server to use the provided location information. Other entities, such as the visited network and possibly AAA brokers MUST NOT use the location information for a purpose other than described in this document. More extensible authorization policies can be stored at the user's home network. These policies are useful when location information is distributed to other entities in a location-based service. This scenario is, however, outside the scope of this document. It is necessary to use authorization policies to limit the unauthorized distribution of location information. The security requirements which are created based on  are inline with threats which appear in the relationship with disclosure of location information as described in .. PIDF-LO  proposes S/MIME to protect the Location Object against modifications. S/SIME relies on public key cryptography which raises performance, deployment and size considerations. Encryption would require that the local AAA server or the NAS knows the recipient's public key (e.g., the public key of the home AAA server). Knowing the final recipient of the location information is in many cases difficult for RADIUS entities. Some sort of public key infrastructure would be required to obtain the public key and to verify the digital signature (at the home network). Providing per-object cryptographic protection is, both at the home and at the visited network, computationally expensive. If no authentication, integrity and replay protection between the participating RADIUS entities is provided then an adversaries can spoof and modify transmitted AVPs.attributes. Two security mechanisms are proposed for RADIUS: o  proposes the usage of a static key which might raise some concerns about the lack dynamic key management. o RADIUS over IPsec  allows to run standard key management mechanisms, such as KINK ,, IKE and IKEv2 ,, to establish IPsec security associations. Confidentiality protection MUST be used to prevent eavesdropper gaining access to location information. Confidentiality protection is not only a property required by this document, it is also required for the transport of keying material in the context of EAP authentication and authorization. Hence, this requirement is, in many environments, already fulfilled. Mutual authentication must be provided between the local AAA server and the home AAA server to prevent man-in- the-middle attacks from being successful. This is another requirement raised in the area of key transport with RADIUS and does not represent a deployment obstacle. The performance advantages superior compared to the usage of S/MIME and object security since the expensive authentication and key exchange protocol run needs to be provided only once (for a long time). Symmetric channel security with IPsec is highly efficient. Since IPsec protection is suggested as a mechanism to protect RAIDUS already no additional considerations need to be addressed beyond those described in .. Where an untrusted AAA intermediary is present, the Location Object MUST NOT be provided to the intermediary. In case that IPsec protection is not available for some reason and RADIUS specific security mechanisms have to be used then the following considerations apply. The Access-Request message is not integrity protected. This would allow an adversary to change the contents of the Location Object or to insert and modify attributes and fields or to delete attributes. To address these problems the Message-Authenticator (80) can be used to integrity protect the entire Access-Request packet. The Message-Authenticator (80) is also required when EAP is used and hence is supported by many modern RADIUS servers. Access-Request packets including Location attribute(s) without a Message-Authenticator(80) attribute SHOULD be silently discarded by the RADIUS server. A RADIUS server supporting the Location attributes MUST calculate the correct value of the Message- Authenticator(80) and MUST silently discard the packet if it does not match the value sent. Access-Accept, including Location attribute(s) without a Message- Authenticator(80) attribute SHOULD be silently discarded by the NAS. A NAS supporting the Location attribute MUST calculate the correct value of a received Message-Authenticator(80) and MUST silently discard the packet if it does not match the value sent. RADIUS and DIAMETERDiameter make some assumptions about the trust between traversed AAA entities in sense that object level security is not provided by neither RADIUS nor DIAMETER.Diameter. Hence, some trust has to be placed on the AAA entities to behave according to the defined rules. Furthermore, the AAA protocols do not involve the user in their protocol interaction except for tunneling authentication information (such as EAP messages) through their infrastructure. RADIUS and DIAMETERDiameter have even become a de-facto protocol for key distribution. Hence, in the past there were some concerns about the trust placed into the infrastructure particularly from the security area when it comes to keying. The EAP keying infrastructure is described in . 16.. 15. IANA Considerations The authors request that the Attribute Types, and Attribute Values defined in this document be registered by the Internet Assigned Numbers Authority (IANA) from the RADIUS name spaces as described in the "IANA Considerations" section of RFC 2865 ,3575 , in accordance with BCP 26 .. Additionally, the Attribute Type should be registered in the Diameter name space. This document defines the following AVPs:attributes: Operator-Name Operator-NamespaceLocation-Information Basic-Policy-Rules Extended-Policy-Rules Location-Name CapabilityChallenge-Capable Requested-Info Please refer to Section 1110 for the registered list of numbers. This document also instructs IANA to assign a new value for the Error-Cause attribute , of "Location-Info-Required" TBA. Additionally, IANA is requested to create the following new registries: 16.115.1. New Registry: Operator Type This document also defines aan operator namespace registry for(used in the Operator-Namespace attribute.Namespace field of the Operator-Name attribute). Initially, IANA is requested to register the following valuesattribues: identifier and operator-namespace / associated registry owners for the operator namespace: +--------------------+----------------------------+ |+----------+--------------------------------------+ |Identifier| Operator-Namespace |/ Registry Owner | +--------------------+----------------------------++----------+--------------------------------------+ | GSM0 | GSM Association: TADIG- GSM Association/TADIG WG | | CDMA1 | CDMA - IMSI Oversight Council | | REALM2 | REALM - IANA or delegate | +--------------------+----------------------------+| 3 | ITU - ITU-T/TSB | +----------+--------------------------------------+ Following the policies outline in  new Operator-Namespaces will be assigned after Expert Review by the Geopriv working group or its designated successor. 16.2Updates can be provided based on expert approval only. No mechanism to mark entries entries as "deprecated" is envisioned. Based on expert approval it is possible to delete entries from the registry. 15.2. New Registry: CapabilitiesRequested-Info attribute This document creates a new IANA registry for capabilities.the Requested-Info attribute. Currently two capabilitiesfour info elements are defineddefined, as shown in Section 10.77 Following the policies outline in RFC 2434 , these tokens are new Operator-Namespaces will be assigned after Expert Review by the RADEXT working group or its designated successor. Updates can be provided based on a 'First Come First Served' policy.expert approval only. A designated expert will be appointed by the O&M Area Directors. No mechanism to mark entries entries as "deprecated is envisioned. Based on expert approval it is possible to delete entries from the registry. Each registration must include the name of the capability,info element, a brief description and a numerical value respresenting a bit in the capability bit-string: Capabilitybit- string: Name: Identifier of the capability Description: Brief description indicating the meaning of the capability.info element. Numerical Value: A numerical value that is placed into the Capability attribute. 17.16. Acknowledgments The authors would like to thank the following people for their help with a previous version of this draft and for their input: Chuck Black Paul Congdon Jouni Korhonen Sami Ala-luukko Farooq Bari Ed Van Horne Mark Grayson Jukka Tuomi Jorge Cuellar Christian Guenther Henning Schulzrinne provided the civic location information content found in this draft. The geospatial location information format is based on work done by J. Polk, J. Schnizlein and M. Linsner. The authorization policy format is based on the work done by Jon Peterson. The authors would like to thank Victor Lortz, Jose Puthenkulam, Bernrad Aboba, Jari Arkko, Parviz Yegani, Serge Manning, Kuntal Chowdury, Pasi Eronen, Blair Bullock and Eugene Chang for their feedback to an initial version of this draft. We would like to thank Jari Arkko for his text contributions. Lionel Morand provided detailed feedback on numerous issues. His comments helped to improve the quality of this document. Jouni Korhonen and John Loughney helped us with the Diameter RADIUS interoperability. Finally,Andreas Pashalidis reviewed the final document and provided a number of comments. Bernard Aboba, Alan DeKok, Lionel Morand, Jouni Korhonen, David Nelson and Emile van Bergen provided guidance on the Requested- Info attribute and participated in the capability exchange discussions. This document is based on the discussions within the IETF GEOPRIV working group. Therefore, the authors thank Henning Schulzrinne, James Polk, John Morris, Allison Mankin, Randall Gellens, Andrew Newton, Ted Hardie, Jon Peterson for their time to discuss a number of issues with us. We thank Stephen Hayes for aligning this work with 3GPP activities. 18.17. References 18.117.1. Normative References  Rigney, C., Willens, S., Rubens, A., and W. Simpson, "Remote Authentication Dial In User Service (RADIUS)", RFC 2865, June 2000.  Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", March 1997.  Rigney, C., "RADIUS Accounting", RFC 2866, June 2000.  Schulzrinne, H., "Dynamic Host Configuration Protocol (DHCPv4 and DHCPv6) Option for Civic Addresses Configuration Information", draft-ietf-geopriv-dhcp-civil-06draft-ietf-geopriv-dhcp-civil-09 (work in progress), May 2005.January 2006.  Chiba, M., Dommety, G., Eklund, M., Mitton, D., and B. Aboba, "Dynamic Authorization Extensions to Remote Authentication Dial In User Service (RADIUS)", RFC 3576, July 2003.  Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD 63, RFC 3629, November 2003.  Schulzrinne, H. and H. Tschofenig, "Location Types Registry", draft-ietf-geopriv-location-types-registry-03 (work in progress), August 2005.  Polk, J., Schnizlein, J., and M. Linsner, "Dynamic Host Configuration Protocol Option for Coordinate-based Location Configuration Information", RFC 3825, July 2004.  Schulzrinne, H. and H. Tschofenig, "Location Types Registry", draft-ietf-geopriv-location-types-registry-01 (work in progress), July 2005. Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J. Arkko, "Diameter Base Protocol", RFC 3588, September 2003.  Aboba, B., "IANA Considerations for RADIUS (Remote Authentication Dial In User Service)", RFC 3575, July 2003.  Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. 18.217.2. Informative References  Cuellar, J., Morris, J., Mulligan, D., Peterson, D., and D. Polk, "Geopriv Requirements", RFC 3693, February 2004.  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, June 2002.  Polk, J. and B. Rosen, "Session Initiation Protocol Location Conveyance", draft-ietf-sip-location-conveyance-00draft-ietf-sip-location-conveyance-01 (work in progress), JuneJuly 2005.  Peterson, J., "A Presence-based GEOPRIV Location Object Format", draft-ietf-geopriv-pidf-lo-03 (work in progress), September 2004.  Schulzrinne, H., "A Document Format for Expressing Privacy Preferences", draft-ietf-geopriv-common-policy-04draft-ietf-geopriv-common-policy-06 (work in progress), FebruaryOctober 2005.  Schulzrinne, H., "A Document Format for Expressing Privacy Preferences for Location Information", draft-ietf-geopriv-policy-05draft-ietf-geopriv-policy-07 (work in progress), November 2004. October 2005.  Calhoun, P., Zorn, G., Spence, D., and D. Mitton, "Diameter Network Access Server Application", draft-ietf-aaa-diameter-nasreq-17 (work in progress), July 2004.  Mills, D., "Network Time Protocol (Version 3) Specification, Implementation", RFC 1305, March 1992.  "Open Geography Markup Language (GML) Implementation Specification", OGC 02-023r4, http://www.opengis.org/techno/implementation.htm", , January 2003.  Stanley, D., Walker, J., and B. Aboba, "Extensible Authentication Protocol (EAP) Method Requirements for Wireless LANs", RFC 4017, March 2005.  Narten, T. and R. Draves, "Privacy Extensions for Stateless Address Autoconfiguration in IPv6", RFC 3041, January 2001.  Simpson, W., "PPP Challenge Handshake Authentication Protocol (CHAP)", RFC 1994, August 1996.  Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H. Levkowetz, "Extensible Authentication Protocol (EAP)", RFC 3748, June 2004.  Aboba, B., "The Network Access Identifier", draft-ietf-radext-rfc2486bis-05draft-ietf-radext-rfc2486bis-06 (work in progress), FebruaryJuly 2005.  Arkko, J. and H. Haverinen, "Extensible Authentication Protocol Method for 3rd Generation Authentication and Key Agreement (EAP-AKA)", draft-arkko-pppext-eap-aka-15 (work in progress), December 2004.  Josefsson, S., Palekar, A., Simon, D., and G. Zorn, "Protected EAP Protocol (PEAP) Version 2", draft-josefsson-pppext-eap-tls-eap-10 (work in progress), October 2004.  Tschofenig, H., "EAP IKEv2 Method (EAP-IKEv2)", draft-tschofenig-eap-ikev2-06Method", draft-tschofenig-eap-ikev2-09 (work in progress), May 2005. February 2006.  Adrangi, F., "Chargeable User Identity", draft-ietf-radext-chargeable-user-id-05draft-ietf-radext-chargeable-user-id-06 (work in progress), MayOctober 2005.  Danley, M., "Threat Analysis of the Geopriv Protocol", RFC 3694, September 2003.  Aboba, B. and P. Calhoun, "RADIUS (Remote Authentication Dial In User Service) Support For Extensible Authentication Protocol (EAP)", RFC 3579, September 2003.  Sakane, S., "Kerberized Internet Negotiation of Keys (KINK)", draft-ietf-kink-kink-08draft-ietf-kink-kink-11 (work in progress), JulyDecember 2005.  Kaufman, C., "Internet Key Exchange (IKEv2) Protocol", draft-ietf-ipsec-ikev2-17 (work in progress), October 2004.  Aboba, B., "Extensible Authentication Protocol (EAP) Key Management Framework", draft-ietf-eap-keying-06draft-ietf-eap-keying-09 (work in progress), April 2005. January 2006.  Schulzrinne, H., "RPID: Rich Presence Extensions to the Presence Information Data Format (PIDF)", draft-ietf-simple-rpid-07draft-ietf-simple-rpid-10 (work in progress), JuneDecember 2005.  Adrangi, F., "Access Network Bandwidth Capability", draft-adrangi-radius-bandwidth-capability-01 (work in progress), July 2004.  Aboba, B., "The Network Access Identifier", draft-arkko-roamops-rfc2486bis-02 (work in progress), July 2004. Authors' Addresses Hannes Tschofenig Siemens Otto-Hahn-Ring 6 Munich, Bavaria 81739 Germany Email: Hannes.Tschofenig@siemens.com F.Farid Adrangi Intel Corporatation 2111 N.E. 25th Avenue Hillsboro OR USA Email: email@example.com Mark Jones Bridgewater Systems Corporation 303 Terry Fox Drive Ottawa, Ontario K2K 3J1 CANADA Email: firstname.lastname@example.org Avi Lior Bridgewater Systems Corporation 303 Terry Fox Drive Ottawa, Ontario K2K 3J1 CANADA Email: email@example.com Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. 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