Geopriv H. Tschofenig
Internet-Draft Siemens
Intended status: Informational F. Adrangi
Expires: February 13, 2007 Intel
M. Jones
A. Lior
Bridgewater
August 12, 2006
Carrying Location Objects in RADIUS
draft-ietf-geopriv-radius-lo-08.txt
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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 . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Delivery Methods for Location Information . . . . . . . . . . 6
3.1. Authentication/Authorization Phase Delivery . . . . . . . 6
3.2. Mid-session Authorization . . . . . . . . . . . . . . . . 9
4. Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1. Scenario 1 - Use of Location Information in AAA . . . . . 11
4.2. Scenario 2 - Use of Location Information for Other
Services . . . . . . . . . . . . . . . . . . . . . . . . . 12
5. Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1. Operator-Name Attribute . . . . . . . . . . . . . . . . . 13
5.2. Location-Information Attribute . . . . . . . . . . . . . . 16
5.3. Location-Info-Civic Attribute . . . . . . . . . . . . . . 18
5.4. Location-Info-Geo Attribute . . . . . . . . . . . . . . . 19
5.5. Basic Policy Rules Attribute . . . . . . . . . . . . . . . 21
5.6. Extended Policy Rules Attribute . . . . . . . . . . . . . 25
5.7. Challenge-Capable Attribute . . . . . . . . . . . . . . . 26
5.8. Requested-Info Attribute . . . . . . . . . . . . . . . . . 26
6. Table of Attributes . . . . . . . . . . . . . . . . . . . . . 32
7. Diameter RADIUS Interoperability . . . . . . . . . . . . . . . 33
8. Matching with Geopriv Requirements . . . . . . . . . . . . . . 34
8.1. Distribution of Location Information at the User's
Home Network . . . . . . . . . . . . . . . . . . . . . . . 34
8.2. Distribution of Location Information at the Visited
Network . . . . . . . . . . . . . . . . . . . . . . . . . 35
8.3. Requirements matching . . . . . . . . . . . . . . . . . . 36
9. Privacy Considerations . . . . . . . . . . . . . . . . . . . . 42
9.1. Entity in the visited network . . . . . . . . . . . . . . 42
9.2. Entity in the home network . . . . . . . . . . . . . . . . 43
10. Security Considerations . . . . . . . . . . . . . . . . . . . 46
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 49
11.1. New Registry: Operator Type . . . . . . . . . . . . . . . 49
11.2. New Registry: Requested-Info attribute . . . . . . . . . . 50
12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 51
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 53
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13.1. Normative References . . . . . . . . . . . . . . . . . . . 53
13.2. Informative References . . . . . . . . . . . . . . . . . . 53
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 56
Intellectual Property and Copyright Statements . . . . . . . . . . 57
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1. Introduction
Wireless LAN (WLAN) access networks are being deployed in public
places such as airports, hotels, shopping malls, and coffee shops by
a diverse set of operators such as cellular network operators (GSM
and CDMA), Wireless Internet Service Providers (WISPs), and fixed
broadband operators.
When a user executes the network access authentication procedure to
such a network, information about the location and ownership of this
network needs to be conveyed to the user's home network to which the
user has a contractual relationship. The main intent of this
document is to enable location aware billing (e.g., by determining
the appropriate tariff and taxation in dependence of the location of
the access network and the end host), location aware subscriber
authentication and authorization for roaming environments and to
enable other location aware services.
This document describes AAA attributes, which are used by a AAA
client or a AAA proxy in an access network, to convey location-
related information to the user's home AAA server.
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. [10] 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.
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2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [1].
RADIUS specific terminology is borrowed from [2] and [3].
Terminology related to privacy issues, location information and
authorization policy rules is taken from [10].
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 authentication to the AAA server
location information is sent from the AAA client to the AAA server.
The authenticated identity might 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 better term).
Furthermore, the authors believe that there is a relationship between
the NAS (or other nodes in the access network) and the location of
the entity that triggered the network access authentication, such as
the user. The NAS might in many cases know the location of the end
host through various techniques (e.g., wire databases, wireless
triangulation). Knowing the location of a network (where the user or
end host is attached) might in many networks also reveal enough
information about the location of the user or the end host. A
similar assumption is also made with regard to the location
information obtained via DHCP (see for example [4]). This
information might be used by applications in other protocols (such as
SIP [11] with extensions [12]) 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. This
assumption might not hold in all scenarios but seems to be reasonable
and practicable.
Please note that the authors use the terms end host and user
interchangably.
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3. Delivery Methods for Location Information
Location Objects, which consist of location information and privacy
rules, are transported via the RADIUS protocol from the AAA client to
the AAA server. A few attributes are introduced for this purpose, as
listed in Section 5, whereby delivery to the RADIUS server can happen
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 flows for both delivery methods.
3.1. Authentication/Authorization Phase Delivery
Figure 1 shows an example message flow for delivering location
information during the network access authentication and
authorization procedure. Upon a network authentication request from
an access network client, the NAS submits a RADIUS Access-Request
message that contains location information attributes among other
required attributes. These attributes are added based on various
criteria (such as local policy, business relationship with
subscriber's home network provider and in case of location
information also by considering privacy policies).
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+---------+ +---------+ +---------+
| Network | | Network | | AAA |
| Access | | Access | | Server |
| Client | | Server | | |
+---------+ +---------+ +---------+
| | |
| Authentication phase | |
| begin | |
|---------------------->| |
| | |
| | RADIUS |
| | Access-Request |
| | + Location-Information |
| |----------------------------->|
| | |
| | RADIUS |
| | Access-Accept |
| |<-----------------------------|
| Authentication | |
| Success | |
|<----------------------| |
| | |
| | RADIUS |
| | Accounting-Request |
| | + Location-Information |
| |----------------------------->|
| | |
Figure 1: Location Delivery based on out-of-band Agreements
If no location information is provided by the RADIUS client although
it is needed by the RADIUS server to compute the authorization
decision then the RADIUS server challenges the RADIUS client. This
exchange is shown in Figure 2. The Access-Challenge thereby provides
a hint to the Network Access Server regarding the type of location
information 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 message the
authorization procedure at the RADIUS server might be based on a
number of criteria, including the newly defined attributes listed in
Section 5.
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+---------+ +---------+ +---------+
| 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 Request
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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 (if privacy
policy allow it) and 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 [5]. At anytime during the session the
RADIUS server MAY send a COA message containing session
identification attributes and a Requested-Info attribute attribute to
the AAA client if authorization policies allow it. 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 includes location information in this
Access-Request if policies allow it.
Figure 3 shows the approach graphically.
+---------+ +---------+
| AAA | | AAA |
| Client | | Server |
| (NAS) | | |
+---------+ +---------+
| |
| COA + Service-Type "Authorize Only" |
| + Requested-Info |
|<----------------------------------------------|
| |
| COA NAK + Service-Type "Authorize Only" |
| + Error-Cause "Request Initiated" |
|---------------------------------------------->|
| |
| Access-Request + Service-Type "Authorize Only"|
| + Location-Information |
| + Policy-Rules |
|---------------------------------------------->|
| |
| Access-Accept |
|<----------------------------------------------|
| |
Figure 3: Mid-session Authorization
Upon receiving the Access-Request message containing the Service-Type
hint attribute with a value of Authorize-Only from the NAS, the
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RADIUS server responds with either an Access-Accept or an Access-
Reject message.
Since location information can be sent in accounting records
(including accounting interim records), RFC 3576 [5] is only needed
for authorization changes.
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4. Scenarios
In the following subsections we describe two scenarios for use of
location information. Location information may refer to the
(visited) network or to the end host. How the network obtains the
end hosts location information is out of the scope of this document.
There are two potential consumers of location information: the AAA
server and location-based services. The privacy implications of
these scenarios are described in Section 9.
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 only. The NAS delivers location information to the home AAA
server.
The location of the AAA client and/or the end host is transferred
from the NAS to the RADIUS server (based on a pre-established
agreement or if the RADIUS server asks for it under consideration of
privacy policies). The NAS and intermediaries (if any) are not
allowed to use that information other than to forward it to the home
network.
The RADIUS server authenticates and authorizes the user requesting
access to the network. If the user's location policies are available
to the RADIUS server, the RADIUS server MUST deliver those policies
in an Access Accept to the RADIUS client. This information MAY be
needed if intermediaries or other elements want to act as Location
Servers (see Section 4.2). If the NAS or intermediaries do not
receive policies 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 tariffs or 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.
Location information in the accounting stream MUST only be sent in
the proxy chain to the home network (unless specified otherwise).
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4.2. Scenario 2 - Use of Location Information for Other Services
Location Servers are entities that receive the user's location
information and transmit it to other entities. In this second
scenario, Location Servers comprise also the NAS and the RADIUS
server. The RADIUS servers are in the home network, in the visited
network, or in broker networks.
Unless explicitly authorized by the user's location policy, location
information MUST NOT be transmitted to other parties outside the
proxy chain between the NAS and the Home RADIUS server.
Upon authentication and authorization, the home RADIUS server MUST
transmit the ruleset (if available) in an Access-Accept. The RADIUS
client, intermediate proxies are allowed to share location
information if they received ruleset indicates that it is allowed.
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5. Attributes
5.1. Operator-Name Attribute
This attribute contains the operator namespace and the operator name.
The operator name is combined with the namespace to uniquely identify
the owner of an access network. The value of the Operator-Name is a
non-NULL terminated string whose length MUST NOT exceed 253 bytes.
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-Name attribute is shown below.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value (cont.) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type:
To Be Assigned by IANA - Operator-Name
Length:
>= 5
Value:
The Value field is at least two octets in length, and the format
is shown below. The data type of the Value field is string.
All fields are transmitted from left to right:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Namespace | Operator-Name ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Operator-Name ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Namespace:
The value within this field contains the
Operator Namespace identifier. The Namespace value
is encoded as an 8-bit unsigned integer value.
Example: 2 for REALM
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
The Namespace field provides information about the operator
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namespace. This document defines four values for this attribute that
are listed below. Defining additional namespaces requires IANA
registration and MUST be associated with an organization responsible
for managing this namespace.
TADIG (0):
This namespace can be used to indicate operator names based on
Transferred Account Data Interchange Group (TADIG) codes defined
in [13]. TADIG codes are assigned by the TADIG Working Group
within the GSM Association. The TADIG Code consists of two
fields, with a total length of five ASCII characters consisting of
a three-character country code and a two-character aplhanumeric
operator (or company) ID.
E212 (1):
The E212 namespace can be used to indicate operator names based on
the Mobile Country Code (MCC) and Mobile Network Code (MNC)
defined in [14]. The MCC/MCC values are assigned by the
Telecommunications Standardization Bureau (TSB) within the ITU-T
and designated administrators in different countries. The E212
value consists of three ASCII digits containing the MCC, followed
by two or three ASCII digits containing the MNC.
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).
ICC (3):
The ICC namespace can be used to indicate operator names based on
ITU Carrier Codes (ICC) defined in [15]. ICC values are assigned
by national regulatory authorities and are coordinated by the
Telecommunication Standardization Bureau (TSB) within the ITU-T.
When using the ICC namespace, the attribute consists of three
uppercase ASCII characters containing a three-letter alphabetic
country code as defined in [16], followed by one to six uppercase
alphanumeric ASCII characters containing the ICC itself.
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5.2. Location-Information Attribute
The Location-Information attribute SHOULD be sent in Access-Request
and in Accounting-Request messages. For the Accounting-Request
message the Acc-Status-Type may be set to Start, Interim or Stop.
The Location-Information Attribute provides meta-data about the
location information, such as sighting time, time-to-live, mechanism
that was used to determine the location information, etc. The format
is shown below.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value (cont.) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type:
To Be Assigned by IANA - Location-Information
Length:
>= 21
Value:
The Value field is at least two octets in length, and the format
is shown below. The data type of the Value field is string.
The fields are transmitted from left to right:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Index | Code | Entity |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sighting Time ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sighting Time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Time-to-Live ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Time-to-Live |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Method ...
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Index (16 bits):
The 16-bit unsigned integer value allows to associate
the Location-Information attribute with
Location-Info-Civic and Location-Info-Geo
attributes.
Code (8 bits):
Describes the location format that is carried in this attribute
as an unsigned 8-bit integer value. Two values are defined by
this document:
(0) describes civic location information
(1) describes geospatial location information
Entity (8 bits):
This field encodes which location this attribute refers to as an
unsigned 8-bit integer value. Two values are defined by this
document:
(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 (variable):
Describes the way that the location information was
determined. The values are registered with the 'method' Tokens
registry by RFC 4119. The data type of this
field is a string.
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
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NTP timestamp [17].
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. The latter indicates the 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 [17].
The length of the Location-Information Attribute MUST NOT exceed 253
octets.
5.3. Location-Info-Civic Attribute
Civic location is a popular way to describe the location of an
entity. For the RADIUS protocol civic location information is an
opaque object and the RADIUS server parses the location information
based on the encoding format defined in [4]. The data format
described in Section 3.1 of [4] is used.
Location-Info-Civic attribute SHOULD be sent in Access-Request and in
Accounting-Request messages. For the Accounting-Request message the
Acc-Status-Type may be set to Start, Interim or Stop.
The Location-Information attribute provides information about civic
location information. The format is shown below.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value (cont.) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type:
To Be Assigned by IANA - Location-Info-Civic
Length:
>= 21
Value:
The Value field is at least two octets in length, and the format
is shown below. The data type of the Value field is string.
All fields are transmitted from left to right:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Index | Civic Location ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Civic Location ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Index (16 bits):
The 16-bit unsigned integer value allows to associate
the Location-Info-Civic attribute with the
Location-Information attributes.
Civic Location (variable):
The format of the data is described in Section 3.1 of [4]
whereby the first 14 bits (i.e., the code for this DHCP option,
the length of the DHCP option, and the 'what' element)
are not included.
5.4. Location-Info-Geo Attribute
Geospatial location information is encoded as an opaque object
whereby the format is reused from [6]. The RFC 3825 Location
Configuration Information (LCI) format defined in Section 2 of [6]
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starting with bit 17 (i.e., the code for the DHCP option and the
length field is not included.).
Location-Info-Geo 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 provides information about
geospatial location information. The format is shown below.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value (cont.) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type:
To Be Assigned by IANA - Location-Info-Geo
Length:
>= 21
Value:
The Value field is at least two octets in length, and the format
is shown below. The data type of the Value field is string.
All fields are transmitted from left to right:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Index | Geo Location ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Geo Location ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Index (16 bits):
The 16-bit unsigned integer value allows to associate
the Location-Info-Geo attribute with the
Location-Information attributes.
Geo Location (variable):
The RFC 3825 Location Configuration Information (LCI) format
defined in Section 2 of RFC 3825 starting with starting with
the third octet (i.e., the code for the DHCP option and the
length field is not included).
5.5. Basic Policy Rules Attribute
Policy rules control the distribution of location location
information. In some environments the the AAA client might know the
privacy preferences of the user based on pre-configuration or the
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user communicated them as part of the network attachment. In many
other cases the AAA server (or an entity with a relationship to the
AAA server) might possess the user's authorization policies. The
Basic-Policy-Rules attribute SHOULD be sent in an an Access-Request,
Access-Accept, an Access-Challenge, an Access-Reject and an
Accounting-Request message.
When the AAA client does not know the user's policy then the
following procedure is applicable:
o The AAA client SHOULD NOT attach location information in the
initial Access-Request message but should rather wait for the AAA
server to receive a challenge for location information.
o If a roamig agreement or legal circumstances require the AAA
client to transfer location information in the initial Access-
Request message to the AAA server (even though user specific
policies are not available to the AAA client) then the access
network attaches default authorization policies. In this case
default policies with restrictive privacy settings appropriate for
the respective environment are attached in this case. The
'retransmission-allowed' flag MUST be set to '0' meaning that the
location must not be shared with other parties (other than
forarding them to the user's home network). In case the home
network knows the user's privacy policies then these policies
SHOULD be sent from the RADIUS server to the RADIUS client in a
subsequent response message and these policies will be applied to
further location dissemination and in subsequent RADIUS
interactions (e.g., when attaching location information to
Accounting messages).
Note that the authorization framework defined in [18] and [19]
together with XCAP [20] gives users the ability to change their
privacy policies.
With regard to authorization policies this document reuses work done
in [21] and encodes them in a non-XML format. Two fields ('sighting
time' and 'time-to-live') are additionally included in the Location-
Information attribute to conform to the Geopriv requirements [10],
Section 2.7. Two RADIUS attributes are used for this purpose: Basic-
Policy-Rule and Extended-Policy-Rule attribute. The latter is
defined in Section 5.6. 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.
The format of the Basic-Policy-Rules attribute is shown below.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value (cont.) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type:
To Be Assigned by IANA - Basic-Policy-Rules
Length:
>= 12
Value:
The Value field is at least 8 octets in length, and the format
is shown below. The data type of the Value field is string.
All fields are transmitted from left to right:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Retention Expires ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Retention Expires ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Retention Expires | Note Well ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Note Well ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Flag (16 bits):
Only the first bit (R) is defined and corresponds to the
retransmission-allowed field. All other bits are reserved
and MUST be zero.
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R|o o o o o o o o o o o o o o o|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The symbol 'o' refers to reserved flags.
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Retention Expires (64 bits):
NTP timestamp for the 'retention-expires' field.
Note Well (variable):
This field contains a URI that points to human readable
privacy instructions. The data type of this field is string.
This document reuses fields of the 'usage-rules' element, described
in [21]. 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 [17].
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 into the
'note-well' element of the 'usage-rules' element contained in the
PIDF-LO document (see [21]).
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5.6. Extended Policy Rules Attribute
The Extended-Policy-Rules attribute SHOULD be sent in an Access-
Request, an Access-Accept, an Access-Challenge, an Access-Reject and
in an Accounting-Request message whenever location information is
transmitted.
Ruleset reference field of this attribute is of variable length. It
contains a URI that indicates where the richer ruleset can be found.
This URI SHOULD use the HTTPS URI scheme. As a deviation from [21]
this field only contains a reference and does not carry an attached
extended rule set. This modification is motivated by the size
limitations imposed by RADIUS.
The format 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 | Value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value (cont.) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type:
To Be Assigned by IANA - Extended-Policy-Rules
Length:
>= 4
Value:
The Value field is at least two octets in length, and the format
is shown below. The data type of the Value field is string.
The fields are transmitted from left to right:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ruleset Reference ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Ruleset Reference:
This field contains a URI that points to policy rules.
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5.7. Challenge-Capable Attribute
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 authorization decision. The
Challenge-Capable attribute MUST appear in Access-Request Messages,
if the NAS supports this feature, as a hint to the 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 | Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type:
To Be Assigned by IANA - Challenge-Capable Attribute
Length:
4
Value:
The Value field is two octets long and of type string.
Every bit of the two octets MUST be set to 0.
5.8. Requested-Info Attribute
The 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 processing listed below is not applicable.
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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:
o
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 RADIUS server responds with
an Access-Reject with an Error-Cause attribute (including the
"Location-Info-Required" value). Note that an Access-Reject
message SHOULD only be sent if the RADIUS server MUST use
location information for returning a positive access control
decision.
o If the RADIUS server would like location information in the
Accounting-Request message but does not require it for computing
an authorization decision then an Access-Accept MUST include a
Required-Info attribute. This is typically the case when location
information is used for inclusion to the user's bill only. The
RADIUS client SHOULD attach location information to the
Accounting-Request (unless authorization policies dictate
something different), if it is available.
If the RADIUS server does not send a Requested-Info attribute then
the RADIUS client MUST NOT attach location information to messages to
the RADIUS server. The user's authorization policies, if available,
MUST be consulted by the RADIUS server before requesting location
information delivery from the RADIUS client.
Figure 11 shows a simple protocol exchange where the RADIUS server
indicates the desire to obtain location information, namely civic
location information of the user, to grant access. Since the
Requested-Info attribute is attached to the Access-Challenge the
RADIUS server indicates that location information is required for
computing an authorization decision.
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+---------+ +---------+
| RADIUS | | RADIUS |
| Client | | Server |
+---------+ +---------+
| |
| |
| RADIUS |
| Access-Request |
| + Challenge-Capable |
|----------------------------->|
| |
| RADIUS |
| Access-Challenge |
| + Requested-Info |
| ('CIVIC_LOCATION', |
| 'USERS_LOCATION') |
|<-----------------------------|
| |
| RADIUS |
| Access-Request |
| + Location-Information |
| (civic-location) |
|----------------------------->|
| |
| .... |
Figure 11: RADIUS server requesting location information
The Requested-Info attribute MUST 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-
Accept or in the Access-Challenge message.
A summary of the attribute is shown below.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value (cont.) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value (cont.) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type:
To Be Assigned by IANA - Requested-Info Attribute
Length:
10
Value:
The content of the Value field is shown below.
The data type of the Value field is string.
The fields are transmitted from left to right:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Requested-Info |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Requested-Info |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Requested-Info (64 bits):
This text field contains an integer value that encodes the
requested information attributes.
Each capability value represents a bit position.
This document specifies the following capabilities:
Name:
CIVIC_LOCATION
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Description:
The RADIUS server uses this attribute to request information from
the RADIUS client to be returned. The numerical value
representing CIVIC_LOCATION requires the RADIUS client to attach
civic location attributes.
Numerical Value:
A numerical value of this attribute is '1'.
Name:
GEO_LOCATION
Description:
The RADIUS server uses this attribute to request information from
the RADIUS client to be returned. The numerical value
representing GEO_LOCATION requires the RADIUS client to attach
geospatial location attributes.
Numerical Value:
A numerical value of this attribute is '2'.
Name:
USERS_LOCATION
Description:
The numerical value representing USERS_LOCATION indicates that the
AAA client must sent a Location-Information attribute that
contains location information 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.
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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 value of one (1). A value of one indicates that the location
information in the Location-Information attribute refers to the
AAA client.
Numerical Value:
A numerical value of this attribute is '8'.
If neither the NAS_LOCATION nor the USERS_LOCATION bit is set then
per-default the location of the user's client device MUST be returned
(if authorization policies allow it). If both the NAS_LOCATION and
the USERS_LOCATION bits are set then the location information has to
be put into separate attributes. If neither the CIVIC_LOCATION nor
the GEO_LOCATION bit is set in the Requested-Info attribute then no
location information is returned. If both the CIVIC_LOCATION and the
GEO_LOCATION bits are set then the location information has to be put
into separate attributes. The value of NAS_LOCATION and
USERS_LOCATION refers to the location information requested via
CIVIC_LOCATION and 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 client and the users' client device are
returned in a geospatial location format.
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6. 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+ 0 0 0 0+ TBD Location-Information
0+ 0 0 0 0+ TBD Location-Info-Civic
0+ 0 0 0 0+ TBD Location-Info-Geo
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 0-1 0 0-1 0 TBD Requested-Info
0-1 0 0 0 0 TBD Challenge-Capable
The Location-Information, the Location-Info-Civic and the Location-
Info-Geo attribute MAY appear more than once. For example, if the
server asks for civic and geospatial location information two
Location-Information attributes need to be sent. If multiple
Location-Information attributes are sent then they MUST NOT contain
the same information.
The next table shows the occurrence of the error-cause attribute.
Request Accept Reject Challenge Accounting #
Request
0 0 0-1 0 0 TBD Location-Info-Required
0 0 0-1 0 0 101 Error-Cause
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7. Diameter RADIUS Interoperability
When used in Diameter, the attributes defined in this specification
can be used as Diameter AVPs from the Code space 1-255 (RADIUS
attribute compatibility space). No additional Diameter Code values
are therefore allocated. The data types and flag rules for the
attributes are as follows:
+---------------------+
| AVP Flag rules |
|----+-----+----+-----|----+
| | |SHLD| MUST| |
Attribute Name Value Type |MUST| MAY | NOT| NOT|Encr|
----------------------------------|----+-----+----+-----|----|
Operator-Name OctetString| | P,M | | V | Y |
Location-Information OctetString| M | P | | V | Y |
Location-Info-Civic OctetString| M | P | | V | Y |
Location-Info-Geo OctetString| M | P | | V | Y |
Basic-Policy-Rules OctetString| M | P | | V | Y |
Extended-Policy-Rules OctetString| M | P | | V | Y |
Requested-Info OctetString| M | P | | V | Y |
Challenge-Capable OctetString| | P | | V | Y |
----------------------------------|----+-----+----+-----|----|
The attributes in this specification have no special translation
requirements for Diameter to RADIUS or RADIUS to Diameter gateways;
they are copied as is, except for changes relating to headers,
alignment, and padding. See also Section 4.1 of [7] and Section 9 of
[22].
What this specification says about the applicability of the
attributes for RADIUS Access-Request packets applies in Diameter to
AA-Request [22] or Diameter-EAP-Request [23]. What is said about
Access-Challenge applies in Diameter to AA-Answer [22] or Diameter-
EAP-Answer [23] with Result-Code AVP set to
DIAMETER_MULTI_ROUND_AUTH. What is said about Access-Accept applies
in Diameter to AA-Answer or Diameter-EAP-Answer messages that
indicate success. Similarly, what is said about RADIUS Access-Reject
packets applies in Diameter to AA- Answer or Diameter-EAP-Answer
messages that indicate failure.
What is said about COA-Request applies in Diameter to Re-Auth-Request
[22].
What is said about Accounting-Request applies to Diameter Accounting-
Request [22] as well.
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8. Matching with Geopriv Requirements
This section compares the Geopriv requirements described in [10] and
the approach of distributing Location Objects with RADIUS.
In Section 8.1 and Section 8.2 we discuss privacy implications when
RADIUS is not used according to these usage scenario. In Section 8.3
Geopriv requirements are matched against these two scenarios.
8.1. 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 of 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
|
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Figure 16: Location Server at the Home Network
The term 'Rule Holder' in Figure 16 denotes the entity that creates
the authorization rule set.
8.2. Distribution of Location Information at the Visited Network
This section describes a scenario where location information made
available to Location Recipients by some entity in 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
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.
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visited network | home network
|
+----------+ |
|Location | |
|Recipient | |
| | |
+----------+ |
^ | +----------+
| | | Rule |
| | | Holder |
notification | | |
interface | +----+-----+
| | |
| | rule|interface
v | V
+----------+ | +----------+
|Location | Rule Transport| Home AAA |
|Generator |<------------->| Server |
|& Server | RADIUS | |
+----------+ | +----------+
|
Figure 17: Location Server at the Visited Network
8.3. Requirements matching
Section 7.1 of [10] details the requirements of a "Location Object".
We discuss these requirements in the subsequent list.
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 [24]. This
document uses the civic and geospatial location information
format used in [6] and in [4]. The format of [6] and of [4]
can be convered into a PIDF-LO [21].
* Regarding requirement 1.2, a number of fields in the civic
location information format are optional.
* Regarding requirement 1.3, the inclusion of type of place item
(CAtype 29) used in the DHCP civic format gives a further
classification of the location. This attribute can be seen as
an extension.
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* Regarding requirement 1.4, the location information is not
defined in this document.
* 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 5.2, in Section 5.3 and in Section 5.4.
The corresponding privacy rules are detailed in Section 5.5 and
in Section 5.6.
* 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 Section 5.2, Section 5.3,
Section 5.4 Section 5.5 and in Section 5.6).
* 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 9 it has a number
of advantages if this identifier is not carried in clear. 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 10 describes these security mechanisms offered by the
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RADIUS protocol. The same is true for requirement 2.4.
* Regarding requirement 2.5, Section 5.2, Section 5.3 and
Section 5.4 describe the content of the Location Field. Since
the location format itself is not defined in this document
motion and direction vectors as listed in requirement 2.6 are
not defined.
* Regarding requirement 2.6, this document provides the
capability for the AAA server to indicate what type of location
information it would like to see from the AAA client.
* Regarding requirement 2.7, timing information is provided with
'sighting time' and 'time-to-live' field defined in
Section 5.2.
* Regarding requirement 2.8, a reference to an external (more
detailed rule set) is provided with the Section 5.6 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 reuses civic and
geospatial location information as described in Section 5.4 and
in Section 5.3.
* With the support of civic and geospatial location information
support requirement 3.2 is fulfilled.
* Regarding requirement 3.3, the geospatial location information
used by 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 [6].
* Regarding requirement 3.4, further Location Data Types can be
added via new coordinate reference systems (CRSs) (see Datum
field in [6]) and via extensions to [6] and [4].
Section 7.2 of [10] details the requirements of a "Using Protocol".
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These requirements are listed below:
Req. 4.: The using protocol has to obey the privacy and security
instructions coded in the Location Object 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 10 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 9) 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 [10] 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 that are stored at 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 (see
Section 5.5, Section 5.6 and Section 9 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
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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 9). 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 5.5. A reference to the extended ruleset is carried in
Section 5.6. The format of these rules are described in [18] and
[19].
Req. 11. (Limited Rule language): A limited (or basic) ruleset is
provided by the Policy-Information attribute Section 5.5 (and as
introduced with PIDF-LO [21]).
Section 7.4 of [10] 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 10. The importance for
user identity confidentiality and identity protection has already
been recognized as an important property (see for example a
document on 'EAP Method Requirements for Wireless LANs' [25]).
Req. 13. (Credential Requirements): As described in Section 10
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.
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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 10
these requirements are fulfilled with the usage of IPsec if mutual
authentication refers to the RADIUS entities (acting as various
Geopriv entities) which directly communicate with each other.
Req. 15. (Minimal Crypto): A minimum of security mechanisms are
mandated by the usage of RADIUS. Communication security for
Location Objects between AAA infrastructure elements is provided
by the RADIUS protocol (including IPsec and its dynamic key
management framework) rather than on relying on object security
via S/SIME (which is not available with RADIUS).
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9. 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:
9.1. 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).
When the AAA messages traverses one or more broker networks, the
broker network is bound by the same guidelines as the visited network
with respect to the distribution of location information.
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 set.
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
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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).
9.2. 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 [19]
and in [18] 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
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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 [26].
Some link layers make it possible to avoid MAC addresses or change
them dynamically.
o Network access authentication procedures such as PPP CHAP [27] or
EAP [28] 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 [29] and
by method-specific private identity exchange in the EAP method
(e.g., [29], [30], [31]). Support for identity privacy within
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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 [2] or in some
accounting attribute usage scenarios [32].
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 10.
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10. Security Considerations
Requirements for the protection of a Location Object are defined in
[10]: 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 [21]. 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 [10] are inline with threats
which appear in the relationship with disclosure of location
information as described in [33]. PIDF-LO [21] 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 attributes. Two security mechanisms are
proposed for RADIUS:
o [2] proposes the usage of a static key which might raise some
concerns about the lack dynamic key management.
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o RADIUS over IPsec [34] allows to run standard key management
mechanisms, such as KINK, IKE and IKEv2 [35], 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 RADIUS already no additional considerations
need to be addressed beyond those described in [34]. Where an
untrusted AAA intermediary is present, the Location Object MUST
NOT be provided to the intermediary.
In case that IPsec protection is not available for some reason and
RADIUS specific security mechanisms have to be used then the
following considerations apply. The Access-Request message is not
integrity protected. This would allow an adversary to change the
contents of the Location Object or to insert and modify attributes
and fields or to delete attributes. To address these problems the
Message-Authenticator (80) can be used to integrity protect the
entire Access-Request packet. The Message-Authenticator (80) is also
required when EAP is used and hence is supported by many modern
RADIUS servers.
Access-Request packets including Location attribute(s) without a
Message-Authenticator(80) attribute SHOULD be silently discarded by
the RADIUS server. A RADIUS server supporting the Location
attributes MUST calculate the correct value of the Message-
Authenticator(80) and MUST silently discard the packet if it does not
match the value sent.
Access-Accept, including Location attribute(s) without a Message-
Authenticator(80) attribute SHOULD be silently discarded by the NAS.
A NAS supporting the Location attribute MUST calculate the correct
value of a received Message-Authenticator(80) and MUST silently
discard the packet if it does not match the value sent.
RADIUS and Diameter make some assumptions about the trust between
traversed AAA entities in sense that object level security is not
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provided by neither RADIUS nor Diameter. Hence, some trust has to be
placed on the AAA entities to behave according to the defined rules.
Furthermore, the AAA protocols do not involve the user in their
protocol interaction except for tunneling authentication information
(such as EAP messages) through their infrastructure. RADIUS and
Diameter have even become a de-facto protocol for key distribution.
Hence, in the past there were some concerns about the trust placed
into the infrastructure particularly from the security area when it
comes to keying. The EAP keying infrastructure is described in [28].
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11. 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 3575 [8], in accordance with
BCP 26 [9]. Additionally, the Attribute Type should be registered in
the Diameter name space.
This document defines the following attributes:
Operator-Name
Location-Information
Basic-Policy-Rules
Extended-Policy-Rules
Challenge-Capable
Requested-Info
Please refer to Section 6 for the registered list of numbers.
This document also instructs IANA to assign a new value for the
Error-Cause attribute [5], of "Location-Info-Required" TBA.
Additionally, IANA is requested to create the following new
registries:
11.1. New Registry: Operator Type
This document also defines an operator namespace registry (used in
the Namespace field of the Operator-Name attribute). IANA is
requested to add the following values to this registry using their
identifier and a token for the operator-namespace / registry owner:
+----------+--------------------------------------+
|Identifier| Operator-Namespace / Registry Owner |
+----------+--------------------------------------+
| 0 | TADIG |
| 1 | E212 |
| 2 | REALM |
| 3 | ICC |
+----------+--------------------------------------+
Following the policies outlined in [9] new values to the Operator-
Namespaces will be assigned after Expert Review initiated by the O&M
Area Director in consultation with the RADEXT working group chairs or
the working group chairs of a designated successor working group.
Updates can be provided based on expert approval only. No mechanism
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to mark entries as "deprecated" is envisioned. Based on expert
approval it is possible to delete entries from the registry.
11.2. New Registry: Requested-Info attribute
This document creates a new IANA registry for the Requested-Info
attribute. IANA is requested to add the following four values to
this registry:
+----------+----------------------+
| Value | Capability Token |
+----------+----------------------+
| 1 | CIVIC_LOCATION |
| 2 | GEO_LOCATION |
| 4 | USERS_LOCATION |
| 8 | NAS_LOCATION |
+----------+----------------------+
The semantic of these values is defined in Section 5.8.
Following the policies outline in [8] new Capability Tokens with a
description of their semantic for usage with the Requested-Info
attribute will be assigned after Expert Review initiated by the O&M
Area Directors in consultation with the RADEXT working group chairs
or the working group chairs of a designated successor working group.
Updates can be provided based on expert approval only. A designated
expert will be appointed by the O&M Area Directors. No mechanism to
mark entries as "deprecated" is envisioned. Based on expert approval
it is possible to delete entries from the registry.
Each registration must include:
Name:
Capability Token (i.e., an identifier of the capability)
Description:
Brief description indicating the meaning of the info element.
Numerical Value:
A numerical value that is placed into the Capability attribute
representing a bit in the bit-string of the Requested-Info
attribute.
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12. 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. 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
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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.
The RADEXT working group chairs, David Nelson and Bernard Aboba,
provided several draft reviews and we would like to thank them for
the help and their patience.
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13. References
13.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", March 1997.
[2] Rigney, C., Willens, S., Rubens, A., and W. Simpson, "Remote
Authentication Dial In User Service (RADIUS)", RFC 2865,
June 2000.
[3] Rigney, C., "RADIUS Accounting", RFC 2866, June 2000.
[4] Schulzrinne, H., "Dynamic Host Configuration Protocol (DHCPv4
and DHCPv6) Option for Civic Addresses Configuration
Information", draft-ietf-geopriv-dhcp-civil-09 (work in
progress), January 2006.
[5] Chiba, M., Dommety, G., Eklund, M., Mitton, D., and B. Aboba,
"Dynamic Authorization Extensions to Remote Authentication Dial
In User Service (RADIUS)", RFC 3576, July 2003.
[6] Polk, J., Schnizlein, J., and M. Linsner, "Dynamic Host
Configuration Protocol Option for Coordinate-based Location
Configuration Information", RFC 3825, July 2004.
[7] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J. Arkko,
"Diameter Base Protocol", RFC 3588, September 2003.
[8] Aboba, B., "IANA Considerations for RADIUS (Remote
Authentication Dial In User Service)", RFC 3575, July 2003.
[9] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", BCP 26, RFC 2434, October 1998.
13.2. Informative References
[10] Cuellar, J., Morris, J., Mulligan, D., Peterson, D., and D.
Polk, "Geopriv Requirements", RFC 3693, February 2004.
[11] 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.
[12] Polk, J. and B. Rosen, "Session Initiation Protocol Location
Conveyance", draft-ietf-sip-location-conveyance-03 (work in
progress), June 2006.
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[13] "TADIG Naming Conventions, Version 4.1", GSM Association
Official Document TD.13", , June 2006.
[14] "The international identification plan for mobile terminals and
mobile users, ITU-T Recommendation E.212", , May 2004.
[15] "Designations for interconnections among operators' networks,
ITU-T Recommendation M.1400", , January 2004.
[16] "Codes for the representation of names of countries and their
subdivisions - Part 1: Country codes, ISO 3166-1", , 1997.
[17] Mills, D., "Network Time Protocol (Version 3) Specification,
Implementation", RFC 1305, March 1992.
[18] Schulzrinne, H., "Common Policy: A Document Format for
Expressing Privacy Preferences",
draft-ietf-geopriv-common-policy-11 (work in progress),
August 2006.
[19] Schulzrinne, H., "A Document Format for Expressing Privacy
Preferences for Location Information",
draft-ietf-geopriv-policy-08 (work in progress), February 2006.
[20] Rosenberg, J., "The Extensible Markup Language (XML)
Configuration Access Protocol (XCAP)",
draft-ietf-simple-xcap-11 (work in progress), May 2006.
[21] Peterson, J., "A Presence-based GEOPRIV Location Object
Format", RFC 4119, December 2005.
[22] Calhoun, P., Zorn, G., Spence, D., and D. Mitton, "Diameter
Network Access Server Application", RFC 4005, August 2005.
[23] Eronen, P., Hiller, T., and G. Zorn, "Diameter Extensible
Authentication Protocol (EAP) Application", RFC 4072,
August 2005.
[24] "Open Geography Markup Language (GML) Implementation
Specification", OGC 02-023r4,
http://www.opengis.org/techno/implementation.htm", ,
January 2003.
[25] Stanley, D., Walker, J., and B. Aboba, "Extensible
Authentication Protocol (EAP) Method Requirements for Wireless
LANs", RFC 4017, March 2005.
[26] Narten, T. and R. Draves, "Privacy Extensions for Stateless
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Address Autoconfiguration in IPv6", RFC 3041, January 2001.
[27] Simpson, W., "PPP Challenge Handshake Authentication Protocol
(CHAP)", RFC 1994, August 1996.
[28] Aboba, B., Beadles, M., Arkko, J., and P. Eronen, "The Network
Access Identifier", RFC 4282, December 2005.
[29] Arkko, J. and H. Haverinen, "Extensible Authentication Protocol
Method for 3rd Generation Authentication and Key Agreement
(EAP-AKA)", RFC 4187, January 2006.
[30] 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.
[31] Tschofenig, H., "EAP IKEv2 Method",
draft-tschofenig-eap-ikev2-11 (work in progress), June 2006.
[32] Adrangi, F., Lior, A., Korhonen, J., and J. Loughney,
"Chargeable User Identity", RFC 4372, January 2006.
[33] Danley, M., "Threat Analysis of the Geopriv Protocol",
RFC 3694, September 2003.
[34] Aboba, B. and P. Calhoun, "RADIUS (Remote Authentication Dial
In User Service) Support For Extensible Authentication Protocol
(EAP)", RFC 3579, September 2003.
[35] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol",
RFC 4306, December 2005.
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Authors' Addresses
Hannes Tschofenig
Siemens
Otto-Hahn-Ring 6
Munich, Bavaria 81739
Germany
Email: Hannes.Tschofenig@siemens.com
URI: http://www.tschofenig.com
Farid Adrangi
Intel Corporatation
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Hillsboro OR
USA
Email: farid.adrangi@intel.com
Mark Jones
Bridgewater Systems Corporation
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Ottawa, Ontario K2K 3J1
CANADA
Email: mark.jones@bridgewatersystems.com
Avi Lior
Bridgewater Systems Corporation
303 Terry Fox Drive
Ottawa, Ontario K2K 3J1
CANADA
Email: avi@bridgewatersystems.com
Tschofenig, et al. Expires February 13, 2007 [Page 56]
Internet-Draft Carrying Location Objects in RADIUS August 2006
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Tschofenig, et al. Expires February 13, 2007 [Page 57]
