Network Working Group                                      Bernard Aboba
INTERNET-DRAFT                                                 Microsoft
Category: Proposed Standard
<draft-aboba-radext-wlan-02.txt>
6 March 2006


                       RADIUS Attributes for WLAN

   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 August 10, 2006.

Copyright Notice

   Copyright (C) The Internet Society (2006).

Abstract

   Although AAA support is optional within IEEE 802.11, it is expected
   that many IEEE 802.11 authenticators will function as AAA clients.
   This document proposes additional attributes for use by IEEE 802.11
   authenticators.  The attributes defined in this document are
   compatible with those used within Diameter EAP.








Aboba                       Proposed Standard                   [Page 1]


INTERNET-DRAFT         RADIUS Attributes for WLAN           6 March 2006


Table of Contents

1.     Introduction ..........................................    3
   1.1       Terminology .....................................    3
   1.2       Requirements Language ...........................    4
2.     RADIUS Attributes .....................................    4
   2.1       Allowed-SSID ....................................    4
   2.2       Allowed-Called-Station-Id .......................    5
   2.3       EAP-Key-Name ....................................    5
   2.4       EAP-Peer-ID .....................................    6
   2.5       EAP-Server-ID ...................................    7
   2.6       Mobility-Domain-ID ..............................    8
3.     Table of Attributes ...................................    9
4.     Diameter Considerations ...............................    9
5.     IANA Considerations ...................................   10
6.     Security Considerations ...............................   10
7.     References ............................................   10
  7.1  Normative References ..................................   10
  7.2  Informative References ................................   11
ACKNOWLEDGMENTS ..............................................   11
AUTHORS' ADDRESSES ...........................................   12
Intellectual Property Statement ..............................   12
Disclaimer of Validity .......................................   12
Copyright Statement ..........................................   13



























Aboba                       Proposed Standard                   [Page 2]


INTERNET-DRAFT         RADIUS Attributes for WLAN           6 March 2006


1.  Introduction

   In situations where it is desirable to centrally manage
   authentication, authorization and accounting (AAA) for IEEE 802.11
   wireless LANs, deployment of a backend authentication and accounting
   server is desirable.  In such situations, it is expected that IEEE
   802.11 authenticators will function as AAA clients.  This document
   defines additional attributes suitable for usage by IEEE 802.11
   authenticators acting as AAA clients.

1.1.  Terminology

This document uses the following terms:

Access Point (AP)
          A Station that provides access to the distribution services
          via the wireless medium for associated Stations.

Association
          The service used to establish Access Point/Station mapping and
          enable Station invocation of the distribution system services.

authenticator
          An authenticator is an entity that require authentication from
          the supplicant.  The authenticator may be connected to the
          supplicant at the other end of a point-to-point LAN segment or
          802.11 wireless link.

authentication server
          An authentication server is an entity that provides an
          authentication service to an authenticator.  This service
          verifies from the credentials provided by the supplicant, the
          claim of identity made by the supplicant.

Station (STA)
          Any device that contains an IEEE 802.11 conformant medium
          access control (MAC) and physical layer (PHY) interface to the
          wireless medium (WM).

Supplicant
          A supplicant is an entity that is being authenticated by an
          authenticator.  The supplicant may be connected to the
          authenticator at one end of a point-to-point LAN segment or
          802.11 wireless link.







Aboba                       Proposed Standard                   [Page 3]


INTERNET-DRAFT         RADIUS Attributes for WLAN           6 March 2006


1.2.  Requirements Language

   In this document, several words are used to signify the requirements
   of the specification.  The key words "MUST", "MUST NOT", "REQUIRED",
   "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY",
   and "OPTIONAL" in this document are to be interpreted as described in
   [RFC2119].

2.  RADIUS Attributes

2.1.  Allowed-SSID

   Description

      The Allowed-SSID attribute allows the RADIUS server to specify
      which SSIDs the user is allowed to access.  One or more Allowed-
      SSID attributes MAY be included an Access-Accept or CoA-Request
      packet.  This attribute is not allowed in other RADIUS packets.  A
      summary of the Allowed-SSID Attribute format is shown below.  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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     Type      |  Length       |            String...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Code

      TBD

   Length

      >=3

   String

      The String field contains one or more octets, encoding a single
      SSID, as defined in [IEEE-802.11].  If the SSID included in the
      Allowed-SSID attribute is not supported by the NAS, the attribute
      is silently discarded.  UTF-8 encoded 10646 characters are
      recommended, but a robust implementation SHOULD support the field
      as undistinguished octets.








Aboba                       Proposed Standard                   [Page 4]


INTERNET-DRAFT         RADIUS Attributes for WLAN           6 March 2006


2.2.  Allowed-Called-Station-ID

   Description

      The Allowed-Called-Station-ID attribute allows the RADIUS server
      to specify which Called-Station-IDs the user is allowed to access.
      More than one Allowed-Called-Station-ID attribute MAY be included
      in an Access-Accept or CoA-Request packet.  This attribute is not
      allowed in other RADIUS packets.  A summary of the Allowed-Called-
      Station-ID Attribute format is shown below.  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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     Type      |  Length       |            String...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Code

      TBD

   Length

      >=3

   String

      The String field is one or more octets, containing the layer 2
      endpoint that the user's call terminated on.  For details of the
      encoding, see [RFC2865] and [RFC3580].  Note that this attribute
      MUST NOT include the SSID.  If the Called-Station-ID included in
      the Allowed-Called-Station-ID attribute does not describe a layer
      2 endpoint of the NAS, the attribute is silently discarded.  A
      robust implementation SHOULD support the field as undistinguished
      octets.

2.3.  EAP-Key-Name

   Description

      The EAP-Key-Name Attribute, defined in [RFC4072], contains the EAP
      Session-ID, as described in [KEYFRAME].  Exactly how this
      attribute is used depends on the link layer in question.

      It should be noted that not all link layers use this name and
      existing EAP method implementations do not generate it.  An EAP-
      Key-Name attribute MAY only be included within Access-Request,



Aboba                       Proposed Standard                   [Page 5]


INTERNET-DRAFT         RADIUS Attributes for WLAN           6 March 2006


      Access-Accept and CoA-Request packets.  A summary of the EAP-Key-
      Name Attribute format is shown below.  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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     Type      |  Length       |          String...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Code

      102 [RFC4072]

   Length

      >=2

   String

      The String field, when present, is one or more octets, containing
      the EAP Session-ID, as defined in [KEYFRAME].  Since the NAS
      operates as a pass-through in EAP, it cannot know the EAP Session-
      ID before receiving it from the RADIUS server.  As a result, an
      EAP-Key-Name attribute sent in an Access-Request MUST NOT contain
      any data.  A RADIUS server receiving an Access-Request with an
      EAP-Key-Name attribute containing data MUST silently discard the
      attribute.  In addition, the RADIUS server SHOULD include this
      attribute in an Access-Accept or CoA-Request only if an EAP-Key-
      Name attribute was present in the Access-Request.

2.4.  EAP-Peer-ID

   Description

      The EAP-Peer-ID Attribute contains an the Peer-ID generated by the
      EAP method.  Exactly how this name is used depends on the link
      layer in question.  See [KEYFRAME] for more discussion.  The EAP-
      Peer-ID attribute is only allowed in Access-Request and Access-
      Accept packets.

      It should be noted that not all link layers use this name, and
      existing EAP method implementations do not generate it.  Since the
      NAS operates as a pass-through in EAP, it cannot know the EAP-
      Peer-ID before receiving it from the RADIUS server.  As a result,
      an EAP-Peer-ID attribute sent in an Access-Request MUST NOT
      contain any data.  A home RADIUS server receiving an Access-
      Request an EAP-Peer-ID attribute with non-empty data MUST silently



Aboba                       Proposed Standard                   [Page 6]


INTERNET-DRAFT         RADIUS Attributes for WLAN           6 March 2006


      discard the attribute.  In addition, the home RADIUS server SHOULD
      include this attribute an Access-Accept only if an empty EAP-Peer-
      ID attribute was present in the Access-Request.  A summary of the
      EAP-Peer-ID Attribute format is shown below.  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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     Type      |  Length       |            String...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Code

      TBD

   Length

      >=2

   String

      The String field, when present, is one or more octets containing
      the EAP Peer-ID exported by the EAP method.  For details, see
      [KEYFRAME] Appendix A.  A robust implementation SHOULD support the
      field as undistinguished octets.

2.5.  EAP-Server-ID

   Description

      The EAP-Server-ID Attribute contains the Server-ID generated by
      the EAP method.  Exactly how this name is used depends on the link
      layer in question.  See [KEYFRAME] for more discussion.  The EAP-
      Server-ID attribute is only allowed in Access-Request and Access-
      Accept packets.

      It should be noted that not all link layers use this name, and
      existing EAP method implementations do not generate it.  Since the
      NAS operates as a pass-through in EAP, it cannot know the EAP-
      Server-ID before receiving it from the RADIUS server.  As a
      result, an EAP-Server-ID attribute sent in an Access-Request MUST
      NOT contain any data.  A home RADIUS server receiving in an
      Access-Request an EAP-Server-ID attribute with non-empty data MUST
      silently discard the attribute.  In addition, the home RADIUS
      server SHOULD include this attribute an Access-Accept only if an
      empty EAP-Server-ID attribute was present in the Access-Request.
      A summary of the EAP-Server-ID Attribute format is shown below.



Aboba                       Proposed Standard                   [Page 7]


INTERNET-DRAFT         RADIUS Attributes for WLAN           6 March 2006


      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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     Type      |  Length       |            String...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Code

      TBD

   Length

      >=2

   String

      The String field, when present, is one or more octets, containing
      the EAP Server-ID exported by the EAP method.  For details, see
      [KEYFRAME] Appendix A.  A robust implementation SHOULD support the
      field as undistinguished octets.

2.6.  Mobility-Domain-ID

   Description

      A single Mobility-Domain-ID attribute MAY be included in an
      Access-Request or Accounting-Request, in order to enable the NAS
      to provide the RADIUS server with the Mobility Domain Identifier,
      defined in [IEEE-802.11r].  A summary of the Mobility-Domain-ID
      Attribute format is shown below.  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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     Type      |  Length       |            String...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Code

      TBD

   Length

      >=3




Aboba                       Proposed Standard                   [Page 8]


INTERNET-DRAFT         RADIUS Attributes for WLAN           6 March 2006


   String

      The String field contains one or more octets, encoding a single
      Mobility Domain Identifier as defined in [IEEE-802.11r].  UTF-8
      encoded 10646 characters are recommended, but a robust
      implementation SHOULD support the field as undistinguished octets.

3.  Table of Attributes

   The following table provides a guide to which attributes may be found
   in which kinds of packets, and in what quantity.

   Access-   Access-  Access-  Access-    CoA/Disconnect
   Request   Accept   Reject   Challenge  Req            #    Attribute
   0         0+       0        0          0+             TBD  Allowed-SSID
   0         0+       0        0          0+             TBD  Allowed-Called-Station-Id
   0-1       0-1      0        0          0-1            102  EAP-Key-Name
   0-1       0-1      0        0          0              TBD  EAP-Peer-ID
   0-1       0-1      0        0          0              TBD  EAP-Server-ID
   0-1       0        0        0          0              TBD  Mobility-Domain-ID

   The following table defines the meaning of the above table entries.

     0     This attribute MUST NOT be present in packet.
     0+    Zero or more instances of this attribute MAY be
           present in the packet.
     0-1   Zero or one instance of this attribute MAY be
           present in the packet.

4.  Diameter Considerations

   The EAP-Key-Name attribute is aready defined as a RADIUS attribute
   within Diameter EAP [RFC4072].  Diameter needs to define identical
   attributes with the same Type value for the Allowed-SSID, Allowed-
   Called-Station-ID, EAP-Peer-ID, EAP-Server-ID, and Mobility-Domain-
   ID.  The Allowed-SSID, Allowed-Called-Station-ID, EAP-Peer-ID, EAP-
   Server-ID and Mobility-Domain-ID attributes should be available as
   part of the Diameter EAP application [RFC4072].













Aboba                       Proposed Standard                   [Page 9]


INTERNET-DRAFT         RADIUS Attributes for WLAN           6 March 2006


5.  IANA Considerations

   This specification requires assignment of a RADIUS attribute types
   for the following attributes:

   Attribute                     Type
   =========                     ====
   Allowed-SSID                  TBD
   Allowed-Called-Station-Id     TBD
   EAP-Peer-ID                   TBD
   EAP-Server-ID                 TBD
   Mobility-Domain-ID            TBD

6.  Security Considerations

   Since this document describes the use of RADIUS for purposes of
   authentication, authorization, and accounting in WLANs, it is
   vulnerable to all of the threats that are present in other RADIUS
   applications.  For a discussion of these threats, see [RFC2607],
   [RFC2865], [RFC3162], [RFC3576], [RFC3579], and [RFC3580].

7.  References

7.1.  Normative references

[IEEE-802.11]
          Information technology - Telecommunications and information
          exchange between systems - Local and metropolitan area
          networks - Specific Requirements Part 11:  Wireless LAN Medium
          Access Control (MAC) and Physical Layer (PHY) Specifications,
          IEEE Std. 802.11-2003, 2003.

[IEEE-802.11r]
          Draft Amendment to Standard for Information technology -
          Telecommunications and information exchange between systems -
          Local and metropolitan area networks - Specific Requirements
          Part 11:  Wireless LAN Medium Access Control (MAC) and
          Physical Layer (PHY) Specifications: Amendment 2: Fast BSS
          Transition, IEEE P802.11r/D1.2, February 2006.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
          Requirement Levels", RFC 2119, March, 1997.

[RFC2865] Rigney, C., Rubens, A., Simpson, W. and S. Willens, "Remote
          Authentication Dial In User Service (RADIUS)", RFC 2865, June
          2000.





Aboba                       Proposed Standard                  [Page 10]


INTERNET-DRAFT         RADIUS Attributes for WLAN           6 March 2006


[RFC3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J. and H.
          Levkowetz, "Extensible Authentication Protocol (EAP)", RFC
          3748, June 2004.

[RFC4072] Eronen, P., Hiller, T. and G. Zorn, "Diameter Extensible
          Authentication Protocol (EAP) Application", RFC 4072, August
          2005.

[KEYFRAME]
          Aboba, B., Simon, D., Arkko, J., Eronen, P. and H. Levkowetz,
          "EAP Key Management Framework", draft-ietf-eap-keying-10.txt,
          March 2006.

7.2.  Informative references

[RFC2607] Aboba, B. and J. Vollbrecht, "Proxy Chaining and Policy
          Implementation in Roaming", RFC 2607, June 1999.

[RFC3162] Aboba, B., Zorn, G. and D. Mitton, "RADIUS and IPv6", RFC
          3162, August 2001.

[RFC3575] Aboba, B., "IANA Considerations for RADIUS", RFC 3575, July
          2003.

[RFC3576] 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.

[RFC3579] Aboba, B. and P. Calhoun, "RADIUS Support for Extensible
          Authentication Protocol (EAP)", RFC 3579, September 2003.

[RFC3580] Congdon, P., Aboba, B., Smith, A., Zorn, G. and J. Roese,
          "IEEE 802.1X Remote Authentication Dial In User Service
          (RADIUS) Usage Guidelines", RFC 3580, September 2003.

Acknowledgments

   The authors would like to acknowledge Dorothy Stanley of Agere, and
   Ashwin Palekar of Microsoft.












Aboba                       Proposed Standard                  [Page 11]


INTERNET-DRAFT         RADIUS Attributes for WLAN           6 March 2006


Authors' Addresses

   Bernard Aboba
   Microsoft Corporation
   One Microsoft Way
   Redmond, WA 98052

   EMail: bernarda@microsoft.com
   Phone: +1 425 706 6605
   Fax:   +1 425 936 7329

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.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at ietf-
   ipr@ietf.org.

Disclaimer of Validity

   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
   ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
   INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
   INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.







Aboba                       Proposed Standard                  [Page 12]


INTERNET-DRAFT         RADIUS Attributes for WLAN           6 March 2006


Copyright Statement

   Copyright (C) The Internet Society (2006).  This document is subject
   to the rights, licenses and restrictions contained in BCP 78, and
   except as set forth therein, the authors retain all their rights.

Acknowledgment

   Funding for the RFC Editor function is currently provided by the
   Internet Society.

Open issues

   Open issues relating to this specification are tracked on the
   following web site:

   http://www.drizzle.com/~aboba/RADEXT/


































Aboba                       Proposed Standard                  [Page 13]