Network Working Group                                         P. Calhoun
Request for Comments: 4005                                       G. Zorn
Category: Standards Track                             Cisco Systems Inc.
                                                              D. Spence
                                                             Consultant
                                                              D. Mitton
                                                      Circular Networks
                                                            August 2005


              Diameter Network Access Server Application

Status of This Memo

  This document specifies an Internet standards track protocol for the
  Internet community, and requests discussion and suggestions for
  improvements.  Please refer to the current edition of the "Internet
  Official Protocol Standards" (STD 1) for the standardization state
  and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

  Copyright (C) The Internet Society (2005).

Abstract

  This document describes the Diameter protocol application used for
  Authentication, Authorization, and Accounting (AAA) services in the
  Network Access Server (NAS) environment.  When combined with the
  Diameter Base protocol, Transport Profile, and Extensible
  Authentication Protocol specifications, this application
  specification satisfies typical network access services requirements.

  Initial deployments of the Diameter protocol are expected to include
  legacy systems.  Therefore, this application has been carefully
  designed to ease the burden of protocol conversion between RADIUS and
  Diameter.  This is achieved by including the RADIUS attribute space
  to eliminate the need to perform many attribute translations.

  The interactions between Diameter applications and RADIUS specified
  in this document are to be applied to all Diameter applications.  In
  this sense, this document extends the Base Diameter protocol.









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RFC 4005       Diameter Network Access Server Application    August 2005


Table of Contents

  1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  5
      1.1.  Terminology  . . . . . . . . . . . . . . . . . . . . . .  5
      1.2.  Requirements Language  . . . . . . . . . . . . . . . . .  6
      1.3.  Advertising Application Support  . . . . . . . . . . . .  6
  2.  NAS Calls, Ports, and Sessions . . . . . . . . . . . . . . . .  6
      2.1.  Diameter Session Establishment . . . . . . . . . . . . .  7
      2.2.  Diameter Session Reauthentication or Reauthorization . .  7
      2.3.  Diameter Session Termination . . . . . . . . . . . . . .  8
  3.  NAS Messages . . . . . . . . . . . . . . . . . . . . . . . . .  9
      3.1.  AA-Request (AAR) Command . . . . . . . . . . . . . . . .  9
      3.2.  AA-Answer (AAA) Command  . . . . . . . . . . . . . . . . 11
      3.3.  Re-Auth-Request (RAR) Command  . . . . . . . . . . . . . 13
      3.4.  Re-Auth-Answer (RAA) Command . . . . . . . . . . . . . . 14
      3.5.  Session-Termination-Request (STR) Command  . . . . . . . 15
      3.6.  Session-Termination-Answer (STA) Command . . . . . . . . 15
      3.7.  Abort-Session-Request (ASR) Command  . . . . . . . . . . 16
      3.8.  Abort-Session-Answer (ASA) Command . . . . . . . . . . . 17
      3.9.  Accounting-Request (ACR) Command . . . . . . . . . . . . 17
      3.10. Accounting-Answer (ACA) Command. . . . . . . . . . . . . 19
  4.  NAS Session AVPs . . . . . . . . . . . . . . . . . . . . . . . 20
      4.1.  Call and Session Information . . . . . . . . . . . . . . 21
      4.2.  NAS-Port AVP . . . . . . . . . . . . . . . . . . . . . . 22
      4.3.  NAS-Port-Id AVP  . . . . . . . . . . . . . . . . . . . . 22
      4.4.  NAS-Port-Type AVP  . . . . . . . . . . . . . . . . . . . 22
      4.5.  Called-Station-Id AVP  . . . . . . . . . . . . . . . . . 23
      4.6.  Calling-Station-Id AVP . . . . . . . . . . . . . . . . . 23
      4.7.  Connect-Info AVP . . . . . . . . . . . . . . . . . . . . 24
      4.8.  Originating-Line-Info AVP  . . . . . . . . . . . . . . . 24
      4.9.  Reply-Message AVP  . . . . . . . . . . . . . . . . . . . 25
  5.  NAS Authentication AVPs  . . . . . . . . . . . . . . . . . . . 26
      5.1.  User-Password AVP  . . . . . . . . . . . . . . . . . . . 26
      5.2.  Password-Retry AVP . . . . . . . . . . . . . . . . . . . 27
      5.3.  Prompt AVP . . . . . . . . . . . . . . . . . . . . . . . 27
      5.4.  CHAP-Auth AVP  . . . . . . . . . . . . . . . . . . . . . 27
      5.5.  CHAP-Algorithm AVP . . . . . . . . . . . . . . . . . . . 28
      5.6.  CHAP-Ident AVP . . . . . . . . . . . . . . . . . . . . . 28
      5.7.  CHAP-Response AVP  . . . . . . . . . . . . . . . . . . . 28
      5.8.  CHAP-Challenge AVP . . . . . . . . . . . . . . . . . . . 28
      5.9.  ARAP-Password AVP  . . . . . . . . . . . . . . . . . . . 28
      5.10. ARAP-Challenge-Response AVP. . . . . . . . . . . . . . . 28
      5.11. ARAP-Security AVP. . . . . . . . . . . . . . . . . . . . 29
      5.12. ARAP-Security-Data AVP . . . . . . . . . . . . . . . . . 29
  6.  NAS Authorization AVPs . . . . . . . . . . . . . . . . . . . . 29
      6.1.  Service-Type AVP . . . . . . . . . . . . . . . . . . . . 30
      6.2.  Callback-Number AVP  . . . . . . . . . . . . . . . . . . 32
      6.3.  Callback-Id AVP  . . . . . . . . . . . . . . . . . . . . 32



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RFC 4005       Diameter Network Access Server Application    August 2005


      6.4.  Idle-Timeout AVP . . . . . . . . . . . . . . . . . . . . 32
      6.5.  Port-Limit AVP . . . . . . . . . . . . . . . . . . . . . 32
      6.6.  NAS-Filter-Rule AVP  . . . . . . . . . . . . . . . . . . 32
      6.7.  Filter-Id AVP  . . . . . . . . . . . . . . . . . . . . . 33
      6.8.  Configuration-Token AVP  . . . . . . . . . . . . . . . . 33
      6.9.  QoS-Filter-Rule AVP  . . . . . . . . . . . . . . . . . . 33
      6.10. Framed Access Authorization AVPs . . . . . . . . . . . . 35
            6.10.1.  Framed-Protocol AVP . . . . . . . . . . . . . . 35
            6.10.2.  Framed-Routing AVP. . . . . . . . . . . . . . . 35
            6.10.3.  Framed-MTU AVP. . . . . . . . . . . . . . . . . 35
            6.10.4.  Framed-Compression AVP. . . . . . . . . . . . . 36
      6.11. IP Access Authorization AVPs.. . . . . . . . . . . . . . 36
            6.11.1.  Framed-IP-Address AVP . . . . . . . . . . . . . 36
            6.11.2.  Framed-IP-Netmask AVP . . . . . . . . . . . . . 36
            6.11.3.  Framed-Route AVP. . . . . . . . . . . . . . . . 37
            6.11.4.  Framed-Pool AVP . . . . . . . . . . . . . . . . 37
            6.11.5.  Framed-Interface-Id AVP . . . . . . . . . . . . 37
            6.11.6.  Framed-IPv6-Prefix AVP. . . . . . . . . . . . . 38
            6.11.7.  Framed-IPv6-Route AVP . . . . . . . . . . . . . 38
            6.11.8.  Framed-IPv6-Pool AVP. . . . . . . . . . . . . . 38
      6.12. IPX Access . . . . . . . . . . . . . . . . . . . . . . . 38
            6.12.1.  Framed-IPX-Network AVP. . . . . . . . . . . . . 39
      6.13. AppleTalk Network Access . . . . . . . . . . . . . . . . 39
            6.13.1.  Framed-AppleTalk-Link AVP . . . . . . . . . . . 39
            6.13.2.  Framed-AppleTalk-Network AVP . . . . . . . . .  39
            6.13.3.  Framed-AppleTalk-Zone AVP . . . . . . . . . . . 40
      6.14. AppleTalk Remote Access. . . . . . . . . . . . . . . . . 40
            6.14.1.  ARAP-Features AVP . . . . . . . . . . . . . . . 40
            6.14.2.  ARAP-Zone-Access AVP. . . . . . . . . . . . . . 40
      6.15. Non-Framed Access Authorization AVPs . . . . . . . . . . 40
            6.15.1.  Login-IP-Host AVP . . . . . . . . . . . . . . . 40
            6.15.2.  Login-IPv6-Host AVP . . . . . . . . . . . . . . 41
            6.15.3.  Login-Service AVP . . . . . . . . . . . . . . . 41
      6.16. TCP Services . . . . . . . . . . . . . . . . . . . . . . 42
            6.16.1.  Login-TCP-Port AVP . . . . . . . . . . . . . .  42
      6.17. LAT Services . . . . . . . . . . . . . . . . . . . . . . 42
            6.17.1.  Login-LAT-Service AVP . . . . . . . . . . . . . 42
            6.17.2.  Login-LAT-Node AVP. . . . . . . . . . . . . . . 43
            6.17.3.  Login-LAT-Group AVP . . . . . . . . . . . . . . 43
            6.17.4.  Login-LAT-Port AVP. . . . . . . . . . . . . . . 43
  7.  NAS Tunneling  . . . . . . . . . . . . . . . . . . . . . . . . 44
      7.1.  Tunneling AVP  . . . . . . . . . . . . . . . . . . . . . 44
      7.2.  Tunnel-Type AVP  . . . . . . . . . . . . . . . . . . . . 45
      7.3.  Tunnel-Medium-Type AVP . . . . . . . . . . . . . . . . . 46
      7.4.  Tunnel-Client-Endpoint AVP . . . . . . . . . . . . . . . 46
      7.5.  Tunnel-Server-Endpoint AVP . . . . . . . . . . . . . . . 47
      7.6.  Tunnel-Password AVP  . . . . . . . . . . . . . . . . . . 48
      7.7.  Tunnel-Private-Group-Id AVP  . . . . . . . . . . . . . . 48



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      7.8.  Tunnel-Assignment-Id AVP . . . . . . . . . . . . . . . . 48
      7.9.  Tunnel-Preference AVP  . . . . . . . . . . . . . . . . . 49
      7.10. Tunnel-Client-Auth-Id AVP. . . . . . . . . . . . . . . . 50
      7.11. Tunnel-Server-Auth-Id AVP. . . . . . . . . . . . . . . . 50
  8.  NAS Accounting . . . . . . . . . . . . . . . . . . . . . . . . 50
      8.1.  Accounting-Input-Octets AVP  . . . . . . . . . . . . . . 51
      8.2.  Accounting-Output-Octets AVP . . . . . . . . . . . . . . 52
      8.3.  Accounting-Input-Packets AVP . . . . . . . . . . . . . . 52
      8.4.  Accounting-Output-Packets AVP  . . . . . . . . . . . . . 52
      8.5.  Acct-Session-Time AVP  . . . . . . . . . . . . . . . . . 52
      8.6.  Acct-Authentic AVP . . . . . . . . . . . . . . . . . . . 52
      8.7.  Accounting-Auth-Method AVP . . . . . . . . . . . . . . . 53
      8.8.  Acct-Delay-Time  . . . . . . . . . . . . . . . . . . . . 53
      8.9.  Acct-Link-Count  . . . . . . . . . . . . . . . . . . . . 54
      8.10. Acct-Tunnel-Connection AVP . . . . . . . . . . . . . . . 54
      8.11. Acct-Tunnel-Packets-Lost AVP . . . . . . . . . . . . . . 55
  9.  RADIUS/Diameter Protocol Interactions  . . . . . . . . . . . . 55
      9.1.  RADIUS Request Forwarded as Diameter Request . . . . . . 55
            9.1.1.   RADIUS Dynamic Authorization Considerations . . 59
      9.2.  Diameter Request Forwarded as RADIUS Request . . . . . . 60
            9.2.1.   RADIUS Dynamic Authorization Considerations . . 62
      9.3.  AVPs Used Only for Compatibility . . . . . . . . . . . . 63
            9.3.1.   NAS-Identifier AVP. . . . . . . . . . . . . . . 63
            9.3.2.   NAS-IP-Address AVP. . . . . . . . . . . . . . . 64
            9.3.3.   NAS-IPv6-Address AVP. . . . . . . . . . . . . . 65
            9.3.4.   State AVP . . . . . . . . . . . . . . . . . . . 65
            9.3.5.   Termination-Cause AVP Code Values . . . . . . . 66
            9.3.6.   Origin-AAA-Protocol . . . . . . . . . . . . . . 68
      9.4.  Prohibited RADIUS Attributes . . . . . . . . . . . . . . 69
      9.5.  Translatable Diameter AVPs . . . . . . . . . . . . . . . 69
      9.6.  RADIUS Vendor-Specific Attributes  . . . . . . . . . . . 69
            9.6.1.  Forwarding a Diameter Vendor Specific AVP as a
                    RADIUS VSA . . . . . . . . . . . . . . . . . . . 70
            9.6.2.  Forwarding a RADIUS VSA as a Diameter Vendor
                    Specific AVP . . . . . . . . . . . . . . . . . . 70
  10. AVP Occurrence Tables. . . . . . . . . . . . . . . . . . . . . 71
      10.1. AA-Request/Answer AVP Table. . . . . . . . . . . . . . . 71
      10.2. Accounting AVP Tables. . . . . . . . . . . . . . . . . . 73
            10.2.1.  Accounting Framed Access AVP Table. . . . . . . 74
            10.2.2.  Accounting Non-Framed Access AVP Table. . . . . 76
  11. IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 77
      11.1. Command Codes. . . . . . . . . . . . . . . . . . . . . . 77
      11.2. AVP Codes. . . . . . . . . . . . . . . . . . . . . . . . 78
      11.3. Application Identifier . . . . . . . . . . . . . . . . . 78
      11.4. CHAP-Algorithm AVP Values. . . . . . . . . . . . . . . . 78
      11.5. Accounting-Auth-Method AVP Values. . . . . . . . . . . . 78
      11.6. Origin-AAA-Protocol AVP Values . . . . . . . . . . . . . 78
  12. Security Considerations. . . . . . . . . . . . . . . . . . . . 78



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RFC 4005       Diameter Network Access Server Application    August 2005


  13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 79
      13.1. Normative References . . . . . . . . . . . . . . . . . . 79
      13.2. Informative References . . . . . . . . . . . . . . . . . 80
  14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 83
  Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 84
  Full Copyright Statement . . . . . . . . . . . . . . . . . . . . . 85

1.  Introduction

  This document describes the Diameter protocol application used for
  AAA in the Network Access Server (NAS) environment.  When combined
  with the Diameter Base protocol [BASE], Transport Profile
  [DiamTrans], and EAP [DiamEAP] specifications, this Diameter NAS
  application specification satisfies NAS-related requirements defined
  in RFC 2989 [AAACriteria] and RFC 3169 [NASCriteria].

  Initial deployments of the Diameter protocol are expected to include
  legacy systems.  Therefore, this application has been carefully
  designed to ease the burden of protocol conversion between RADIUS and
  Diameter.  This is achieved by including the RADIUS attribute space
  to eliminate the need to perform many attribute translations.

  The interactions specified in this document between Diameter
  applications and RADIUS are to be applied to all Diameter
  applications.  In this sense, this document extends the Base Diameter
  protocol [BASE].

  First, this document describes the operation of a Diameter NAS
  application.  Then it defines the Diameter message Command-Codes.
  The following sections list the AVPs used in these messages, grouped
  by common usage.  These are session identification, authentication,
  authorization, tunneling, and accounting.  The authorization AVPs are
  further broken down by service type.  Interaction and backward
  compatibility issues with RADIUS are discussed in later sections.

1.1.  Terminology

  The base Diameter [BASE] specification section 1.4 defines most of
  the terminology used in this document.  Additionally, the following
  terms and acronyms are used in this application:

  NAS (Network Access Server) - A device that provides an access
  service for a user to a network.  The service may be a network
  connection or a value-added service such as terminal emulation
  [NASModel].






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  PPP (Point-to-Point Protocol) - A multiprotocol serial datalink.  PPP
  is the primary IP datalink used for dial-in NAS connection service
  [PPP].

  CHAP (Challenge Handshake Authentication Protocol) - An
  authentication process used in PPP [PPPCHAP].

  PAP (Password Authentication Protocol) - A deprecated PPP
  authentication process, but often used for backward compatibility
  [PAP].

  SLIP (Serial Line Interface Protocol) - A serial datalink that only
  supports IP.  A design prior to PPP.

  ARAP (Appletalk Remote Access Protocol) - A serial datalink for
  accessing Appletalk networks [ARAP].

  IPX (Internet Packet Exchange) - The network protocol used by NetWare
  networks [IPX].

  LAT (Local Area Transport) - A Digital Equipment Corp. LAN protocol
  for terminal services [LAT].

  VPN (Virtual Private Network) - In this document, this term is used
  to describe access services that use tunneling methods.

1.2.  Requirements Language

  In this document, the key words "MAY", "MUST", "MUST NOT",
  "OPTIONAL", "RECOMMENDED", "SHOULD", and "SHOULD NOT" are to be
  interpreted as described in [Keywords].

1.3.  Advertising Application Support

  Diameter applications conforming to this specification MUST advertise
  support by including the value of one (1) in the Auth-Application-Id
  of Capabilities-Exchange-Request (CER), AA-Request (AAR), and AA-
  Answer (AAA) messages.  All other messages are defined by [BASE] and
  use the Base application id value.

2.  NAS Calls, Ports, and Sessions

  The arrival of a new call or service connection at a port of a
  Network Access Server (NAS) starts a Diameter NAS message exchange.
  Information about the call, the identity of the user, and the user's
  authentication information are packaged into a Diameter AA-Request
  (AAR) message and sent to a server.




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  The server processes the information and responds with a Diameter
  AA-Answer (AAA) message that contains authorization information for
  the NAS, or a failure code (Result-Code AVP).  A value of
  DIAMETER_MULTI_ROUND_AUTH indicates an additional authentication
  exchange, and several AAR and AAA messages may be exchanged until the
  transaction completes.

  Depending on the Auth-Request-Type AVP, the Diameter protocol allows
  authorization-only requests that contain no authentication
  information from the client.  This capability goes beyond the Call
  Check capabilities described in section 5.6 of [RADIUS] in that no
  access decision is requested.  As a result, service cannot be started
  as a result of a response to an authorization-only request without
  introducing a significant security vulnerability.

  Since no equivalent capability exists in RADIUS, authorization-only
  requests from a NAS implementing Diameter may not be easily
  translated to an equivalent RADIUS message by a Diameter/RADIUS
  gateway.  For example, when a Diameter authorization-only request
  cannot be translated to a RADIUS Call Check, it would be necessary
  for the Diameter/RADIUS gateway to add authentication information to
  the RADIUS Access Request.  On receiving the Access-Reply, the
  Diameter/RADIUS gateway would need to discard the access decision
  (Accept/Reject).  It is not clear whether these translations can be
  accomplished without adding significant security vulnerabilities.

2.1.  Diameter Session Establishment

  When the authentication or authorization exchange completes
  successfully, the NAS application SHOULD start a session context.  If
  the Result-Code of DIAMETER_MULTI_ROUND_AUTH is returned, the
  exchange continues until a success or error is returned.

  If accounting is active, the application MUST also send an Accounting
  message [BASE].  An Accounting-Record-Type of START_RECORD is sent
  for a new session.  If a session fails to start, the EVENT_RECORD
  message is sent with the reason for the failure described.

  Note that the return of an unsupportable Accounting-Realtime-Required
  value [BASE] would result in a failure to establish the session.

2.2.  Diameter Session Reauthentication or Reauthorization

  The Diameter Base protocol allows users to be periodically
  reauthenticated and/or reauthorized.  In such instances, the
  Session-Id AVP in the AAR message MUST be the same as the one present
  in the original authentication/authorization message.




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  A Diameter server informs the NAS of the maximum time allowed before
  reauthentication or reauthorization via the Authorization-Lifetime
  AVP [BASE].  A NAS MAY reauthenticate and/or reauthorize before the
  end, but A NAS MUST reauthenticate and/or reauthorize at the end of
  the period provided by the Authorization-Lifetime AVP.  The failure
  of a reauthentication exchange will terminate the service.

  Furthermore, it is possible for Diameter servers to issue an
  unsolicited reauthentication and/or reauthorization request (e.g.,
  Re-Auth-Request (RAR) message [BASE]) to the NAS.  Upon receipt of
  such a message, the NAS MUST respond to the request with a Re-Auth-
  Answer (RAA) message [BASE].

  If the RAR properly identifies an active session, the NAS will
  initiate a new local reauthentication or authorization sequence as
  indicated by the Re-Auth-Request-Type value.  This will cause the NAS
  to send a new AAR message using the existing Session-Id.  The server
  will respond with an AAA message to specify the new service
  parameters.

  If accounting is active, every change of authentication or
  authorization SHOULD generate an accounting message.  If the NAS
  service is a continuation of the prior user context, then an
  Accounting-Record-Type of INTERIM_RECORD indicating the new session
  attributes and cumulative status would be appropriate.  If a new user
  or a significant change in authorization is detected by the NAS, then
  the service may send two messages of the types STOP_RECORD and
  START_RECORD.  Accounting may change the subsession identifiers
  (Acct-Session-ID, or Acct-Sub-Session-Id) to indicate such sub-
  sessions.  A service may also use a different Session-Id value for
  accounting (see [BASE] section 9.6).

  However, the Diameter Session-ID AVP value used for the initial
  authorization exchange MUST be used to generate an STR message when
  the session context is terminated.

2.3.  Diameter Session Termination

  When a NAS receives an indication that a user's session is being
  disconnected by the client (e.g., LCP Terminate is received) or an
  administrative command, the NAS MUST issue a Session-Termination-
  Request (STR) [BASE] to its Diameter Server.  This will ensure that
  any resources maintained on the servers are freed appropriately.

  Furthermore, a NAS that receives an Abort-Session-Request (ASR)
  [BASE] MUST issue an ASA if the session identified is active and
  disconnect the PPP (or tunneling) session.




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RFC 4005       Diameter Network Access Server Application    August 2005


  If accounting is active, an Accounting STOP_RECORD message [BASE]
  MUST be sent upon termination of the session context.

  More information on Diameter Session Termination is included in
  [BASE] sections 8.4 and 8.5.

3.  NAS Messages

  This section defines the Diameter message Command-Code [BASE] values
  that MUST be supported by all Diameter implementations conforming to
  this specification.  The Command Codes are as follows:

     Command-Name                  Abbrev.  Code   Reference
     -------------------------------------------------------
     AA-Request                      AAR     265     3.1
     AA-Answer                       AAA     265     3.2
     Re-Auth-Request                 RAR     258     3.3
     Re-Auth-Answer                  RAA     258     3.4
     Session-Termination-Request     STR     275     3.5
     Session-Termination-Answer      STA     275     3.6
     Abort-Session-Request           ASR     274     3.7
     Abort-Session-Answer            ASA     274     3.8
     Accounting-Request              ACR     271     3.9
     Accounting-Answer               ACA     271     3.10

3.1.  AA-Request (AAR) Command

  The AA-Request (AAR), which is indicated by setting the Command-Code
  field to 265 and the 'R' bit in the Command Flags field, is used to
  request authentication and/or authorization for a given NAS user.
  The type of request is identified through the Auth-Request-Type AVP
  [BASE].  The recommended value for most RADIUS interoperabily
  situations is AUTHORIZE_AUTHENTICATE.

  If Authentication is requested, the User-Name attribute SHOULD be
  present, as well as any additional authentication AVPs that would
  carry the password information.  A request for authorization SHOULD
  only include the information from which the authorization will be
  performed, such as the User-Name, Called-Station-Id, or Calling-
  Station-Id AVPs.  All requests SHOULD contain AVPs uniquely
  identifying the source of the call, such as Origin-Host and NAS-Port.
  Certain networks MAY use different AVPs for authorization purposes.
  A request for authorization will include some AVPs defined in section
  6.

  It is possible for a single session to be authorized first and then
  for an authentication request to follow.




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RFC 4005       Diameter Network Access Server Application    August 2005


  This AA-Request message MAY be the result of a multi-round
  authentication exchange, which occurs when the AA-Answer message is
  received with the Result-Code AVP set to DIAMETER_MULTI_ROUND_AUTH.
  A subsequent AAR message SHOULD be sent, with the User-Password AVP
  that includes the user's response to the prompt, and MUST include any
  State AVPs that were present in the AAA message.

  Message Format
     <AA-Request> ::= < Diameter Header: 265, REQ, PXY >
                      < Session-Id >
                      { Auth-Application-Id }
                      { Origin-Host }
                      { Origin-Realm }
                      { Destination-Realm }
                      { Auth-Request-Type }
                      [ Destination-Host ]
                      [ NAS-Identifier ]
                      [ NAS-IP-Address ]
                      [ NAS-IPv6-Address ]
                      [ NAS-Port ]
                      [ NAS-Port-Id ]
                      [ NAS-Port-Type ]
                      [ Origin-AAA-Protocol ]
                      [ Origin-State-Id ]
                      [ Port-Limit ]
                      [ User-Name ]
                      [ User-Password ]
                      [ Service-Type ]
                      [ State ]
                      [ Authorization-Lifetime ]
                      [ Auth-Grace-Period ]
                      [ Auth-Session-State ]
                      [ Callback-Number ]
                      [ Called-Station-Id ]
                      [ Calling-Station-Id ]
                      [ Originating-Line-Info ]
                      [ Connect-Info ]
                      [ CHAP-Auth ]
                      [ CHAP-Challenge ]
                    * [ Framed-Compression ]
                      [ Framed-Interface-Id ]
                      [ Framed-IP-Address ]
                    * [ Framed-IPv6-Prefix ]
                      [ Framed-IP-Netmask ]
                      [ Framed-MTU ]
                      [ Framed-Protocol ]
                      [ ARAP-Password ]
                      [ ARAP-Security ]



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RFC 4005       Diameter Network Access Server Application    August 2005


                    * [ ARAP-Security-Data ]
                    * [ Login-IP-Host ]
                    * [ Login-IPv6-Host ]
                      [ Login-LAT-Group ]
                      [ Login-LAT-Node ]
                      [ Login-LAT-Port ]
                      [ Login-LAT-Service ]
                    * [ Tunneling ]
                    * [ Proxy-Info ]
                    * [ Route-Record ]
                    * [ AVP ]

3.2.  AA-Answer (AAA) Command

  The AA-Answer (AAA) message is indicated by setting the Command-Code
  field to 265 and clearing the 'R' bit in the Command Flags field.  It
  is sent in response to the AA-Request (AAR) message.  If
  authorization was requested, a successful response will include the
  authorization AVPs appropriate for the service being provided, as
  defined in section 6.

  For authentication exchanges requiring more than a single round trip,
  the server MUST set the Result-Code AVP to DIAMETER_MULTI_ROUND_AUTH.
  An AAA message with this result code MAY include one Reply-Message or
  more and MAY include zero or one State AVPs.

  If the Reply-Message AVP was present, the network access server
  SHOULD send the text to the user's client to display to the user,
  instructing the client to prompt the user for a response.  For
  example, this capability can be achieved in PPP via PAP.  If the
  access client is unable to prompt the user for a new response, it
  MUST treat the AA-Answer (AAA) with the Reply-Message AVP as an error
  and deny access.

  Message Format

     <AA-Answer> ::= < Diameter Header: 265, PXY >
                     < Session-Id >
                     { Auth-Application-Id }
                     { Auth-Request-Type }
                     { Result-Code }
                     { Origin-Host }
                     { Origin-Realm }
                     [ User-Name ]
                     [ Service-Type ]
                   * [ Class ]
                   * [ Configuration-Token ]
                     [ Acct-Interim-Interval ]



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RFC 4005       Diameter Network Access Server Application    August 2005


                     [ Error-Message ]
                     [ Error-Reporting-Host ]
                   * [ Failed-AVP ]
                     [ Idle-Timeout ]
                     [ Authorization-Lifetime ]
                     [ Auth-Grace-Period ]
                     [ Auth-Session-State ]
                     [ Re-Auth-Request-Type ]
                     [ Multi-Round-Time-Out ]
                     [ Session-Timeout ]
                     [ State ]
                   * [ Reply-Message ]
                     [ Origin-AAA-Protocol ]
                     [ Origin-State-Id ]
                   * [ Filter-Id ]
                     [ Password-Retry ]
                     [ Port-Limit ]
                     [ Prompt ]
                     [ ARAP-Challenge-Response ]
                     [ ARAP-Features ]
                     [ ARAP-Security ]
                   * [ ARAP-Security-Data ]
                     [ ARAP-Zone-Access ]
                     [ Callback-Id ]
                     [ Callback-Number ]
                     [ Framed-Appletalk-Link ]
                   * [ Framed-Appletalk-Network ]
                     [ Framed-Appletalk-Zone ]
                   * [ Framed-Compression ]
                     [ Framed-Interface-Id ]
                     [ Framed-IP-Address ]
                   * [ Framed-IPv6-Prefix ]
                     [ Framed-IPv6-Pool ]
                   * [ Framed-IPv6-Route ]
                     [ Framed-IP-Netmask ]
                   * [ Framed-Route ]
                     [ Framed-Pool ]
                     [ Framed-IPX-Network ]
                     [ Framed-MTU ]
                     [ Framed-Protocol ]
                     [ Framed-Routing ]
                   * [ Login-IP-Host ]
                   * [ Login-IPv6-Host ]
                     [ Login-LAT-Group ]
                     [ Login-LAT-Node ]
                     [ Login-LAT-Port ]
                     [ Login-LAT-Service ]
                     [ Login-Service ]



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RFC 4005       Diameter Network Access Server Application    August 2005


                     [ Login-TCP-Port ]
                   * [ NAS-Filter-Rule ]
                   * [ QoS-Filter-Rule ]
                   * [ Tunneling ]
                   * [ Redirect-Host ]
                     [ Redirect-Host-Usage ]
                     [ Redirect-Max-Cache-Time ]
                   * [ Proxy-Info ]
                   * [ AVP ]

3.3.  Re-Auth-Request (RAR) Command

  A Diameter server may initiate a re-authentication and/or re-
  authorization service for a particular session by issuing a Re-Auth-
  Request (RAR) message [BASE].

  For example, for pre-paid services, the Diameter server that
  originally authorized a session may need some confirmation that the
  user is still using the services.

  If a NAS receives an RAR message with Session-Id equal to a currently
  active session and a Re-Auth-Type that includes authentication, it
  MUST initiate a re-authentication toward the user, if the service
  supports this particular feature.

  Message Format

     <RA-Request>  ::= < Diameter Header: 258, REQ, PXY >
                      < Session-Id >
                      { Origin-Host }
                      { Origin-Realm }
                      { Destination-Realm }
                      { Destination-Host }
                      { Auth-Application-Id }
                      { Re-Auth-Request-Type }
                      [ User-Name ]
                      [ Origin-AAA-Protocol ]
                      [ Origin-State-Id ]
                      [ NAS-Identifier ]
                      [ NAS-IP-Address ]
                      [ NAS-IPv6-Address ]
                      [ NAS-Port ]
                      [ NAS-Port-Id ]
                      [ NAS-Port-Type ]
                      [ Service-Type ]
                      [ Framed-IP-Address ]
                      [ Framed-IPv6-Prefix ]
                      [ Framed-Interface-Id ]



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RFC 4005       Diameter Network Access Server Application    August 2005


                      [ Called-Station-Id ]
                      [ Calling-Station-Id ]
                      [ Originating-Line-Info ]
                      [ Acct-Session-Id ]
                      [ Acct-Multi-Session-Id ]
                      [ State ]
                    * [ Class ]
                      [ Reply-Message ]
                    * [ Proxy-Info ]
                    * [ Route-Record ]
                    * [ AVP ]

3.4.  Re-Auth-Answer (RAA) Command

  The Re-Auth-Answer (RAA) message [BASE] is sent in response to the
  RAR.  The Result-Code AVP MUST be present and indicates the
  disposition of the request.

  A successful RAA transaction MUST be followed by an AAR message.

  Message Format

     <RA-Answer>  ::= < Diameter Header: 258, PXY >
                      < Session-Id >
                      { Result-Code }
                      { Origin-Host }
                      { Origin-Realm }
                      [ User-Name ]
                      [ Origin-AAA-Protocol ]
                      [ Origin-State-Id ]
                      [ Error-Message ]
                      [ Error-Reporting-Host ]
                    * [ Failed-AVP ]
                    * [ Redirected-Host ]
                      [ Redirected-Host-Usage ]
                      [ Redirected-Host-Cache-Time ]
                      [ Service-Type ]
                    * [ Configuration-Token ]
                      [ Idle-Timeout ]
                      [ Authorization-Lifetime ]
                      [ Auth-Grace-Period ]
                      [ Re-Auth-Request-Type ]
                      [ State ]
                    * [ Class ]
                    * [ Reply-Message ]
                      [ Prompt ]
                    * [ Proxy-Info ]
                    * [ AVP ]



Calhoun, et al.             Standards Track                    [Page 14]

RFC 4005       Diameter Network Access Server Application    August 2005


3.5.  Session-Termination-Request (STR) Command

  The Session-Termination-Request (STR) message [BASE] is sent by the
  NAS to inform the Diameter Server that an authenticated and/or
  authorized session is being terminated.

  Message Format

     <ST-Request> ::= < Diameter Header: 275, REQ, PXY >
                     < Session-Id >
                     { Origin-Host }
                     { Origin-Realm }
                     { Destination-Realm }
                     { Auth-Application-Id }
                     { Termination-Cause }
                     [ User-Name ]
                     [ Destination-Host ]
                   * [ Class ]
                     [ Origin-AAA-Protocol ]
                     [ Origin-State-Id ]
                   * [ Proxy-Info ]
                   * [ Route-Record ]
                   * [ AVP ]

3.6.  Session-Termination-Answer (STA) Command

  The Session-Termination-Answer (STA) message [BASE] is sent by the
  Diameter Server to acknowledge the notification that the session has
  been terminated.  The Result-Code AVP MUST be present and MAY contain
  an indication that an error occurred while the STR was being
  serviced.

  Upon sending or receiving the STA, the Diameter Server MUST release
  all resources for the session indicated by the Session-Id AVP.  Any
  intermediate server in the Proxy-Chain MAY also release any
  resources, if necessary.

  Message Format

     <ST-Answer>  ::= < Diameter Header: 275, PXY >
                      < Session-Id >
                      { Result-Code }
                      { Origin-Host }
                      { Origin-Realm }
                      [ User-Name ]
                    * [ Class ]
                      [ Error-Message ]
                      [ Error-Reporting-Host ]



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RFC 4005       Diameter Network Access Server Application    August 2005


                    * [ Failed-AVP ]
                      [ Origin-AAA-Protocol ]
                      [ Origin-State-Id ]
                    * [ Redirect-Host ]
                      [ Redirect-Host-Usase ]
                      [ Redirect-Max-Cache-Time ]
                    * [ Proxy-Info ]
                    * [ AVP ]

3.7.  Abort-Session-Request (ASR) Command

  The Abort-Session-Request (ASR) message [BASE] may be sent by any
  server to the NAS providing session service, to request that the
  session identified by the Session-Id be stopped.

  Message Format

     <AS-Request>  ::= < Diameter Header: 274, REQ, PXY >
                      < Session-Id >
                      { Origin-Host }
                      { Origin-Realm }
                      { Destination-Realm }
                      { Destination-Host }
                      { Auth-Application-Id }
                      [ User-Name ]
                      [ Origin-AAA-Protocol ]
                      [ Origin-State-Id ]
                      [ NAS-Identifier ]
                      [ NAS-IP-Address ]
                      [ NAS-IPv6-Address ]
                      [ NAS-Port ]
                      [ NAS-Port-Id ]
                      [ NAS-Port-Type ]
                      [ Service-Type ]
                      [ Framed-IP-Address ]
                      [ Framed-IPv6-Prefix ]
                      [ Framed-Interface-Id ]
                      [ Called-Station-Id ]
                      [ Calling-Station-Id ]
                      [ Originating-Line-Info ]
                      [ Acct-Session-Id ]
                      [ Acct-Multi-Session-Id ]
                      [ State ]
                    * [ Class ]
                    * [ Reply-Message ]
                    * [ Proxy-Info ]
                    * [ Route-Record ]
                    * [ AVP ]



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RFC 4005       Diameter Network Access Server Application    August 2005


3.8.  Abort-Session-Answer (ASA) Command

  The ASA message [BASE] is sent in response to the ASR.  The Result-
  Code AVP MUST be present and indicates the disposition of the
  request.

  If the session identified by Session-Id in the ASR was successfully
  terminated, Result-Code is set to DIAMETER_SUCCESS.  If the session
  is not currently active, Result-Code is set to
  DIAMETER_UNKNOWN_SESSION_ID.  If the access device does not stop the
  session for any other reason, Result-Code is set to
  DIAMETER_UNABLE_TO_COMPLY.

  Message Format

     <AS-Answer>  ::= < Diameter Header: 274, PXY >
                      < Session-Id >
                      { Result-Code }
                      { Origin-Host }
                      { Origin-Realm }
                      [ User-Name ]
                      [ Origin-AAA-Protocol ]
                      [ Origin-State-Id ]
                      [ State]
                      [ Error-Message ]
                      [ Error-Reporting-Host ]
                    * [ Failed-AVP ]
                    * [ Redirected-Host ]
                      [ Redirected-Host-Usage ]
                      [ Redirected-Max-Cache-Time ]
                    * [ Proxy-Info ]
                    * [ AVP ]

3.9.  Accounting-Request (ACR) Command

  The ACR message [BASE] is sent by the NAS to report its session
  information to a target server downstream.

  Either of Acct-Application-Id or Vendor-Specific-Application-Id AVPs
  MUST be present.  If the Vendor-Specific-Application-Id grouped AVP
  is present, it must have an Acct-Application-Id inside.

  The AVPs listed in the Base MUST be assumed to be present, as
  appropriate.  NAS service-specific accounting AVPs SHOULD be present
  as described in section 8 and the rest of this specification.






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RFC 4005       Diameter Network Access Server Application    August 2005


  Message Format

     <AC-Request> ::= < Diameter Header: 271, REQ, PXY >
                     < Session-Id >
                     { Origin-Host }
                     { Origin-Realm }
                     { Destination-Realm }
                     { Accounting-Record-Type }
                     { Accounting-Record-Number }
                     [ Acct-Application-Id ]
                     [ Vendor-Specific-Application-Id ]
                     [ User-Name ]
                     [ Accounting-Sub-Session-Id ]
                     [ Acct-Session-Id ]
                     [ Acct-Multi-Session-Id ]
                     [ Origin-AAA-Protocol ]
                     [ Origin-State-Id ]
                     [ Destination-Host ]
                     [ Event-Timestamp ]
                     [ Acct-Delay-Time ]
                     [ NAS-Identifier ]
                     [ NAS-IP-Address ]
                     [ NAS-IPv6-Address ]
                     [ NAS-Port ]
                     [ NAS-Port-Id ]
                     [ NAS-Port-Type ]
                   * [ Class ]
                     [ Service-Type ]
                     [ Termination-Cause ]
                     [ Accounting-Input-Octets ]
                     [ Accounting-Input-Packets ]
                     [ Accounting-Output-Octets ]
                     [ Accounting-Output-Packets ]
                     [ Acct-Authentic ]
                     [ Accounting-Auth-Method ]
                     [ Acct-Link-Count ]
                     [ Acct-Session-Time ]
                     [ Acct-Tunnel-Connection ]
                     [ Acct-Tunnel-Packets-Lost ]
                     [ Callback-Id ]
                     [ Callback-Number ]
                     [ Called-Station-Id ]
                     [ Calling-Station-Id ]
                   * [ Connection-Info ]
                     [ Originating-Line-Info ]
                     [ Authorization-Lifetime ]
                     [ Session-Timeout ]
                     [ Idle-Timeout ]



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RFC 4005       Diameter Network Access Server Application    August 2005


                     [ Port-Limit ]
                     [ Accounting-Realtime-Required ]
                     [ Acct-Interim-Interval ]
                   * [ Filter-Id ]
                   * [ NAS-Filter-Rule ]
                   * [ Qos-Filter-Rule ]
                     [ Framed-AppleTalk-Link ]
                     [ Framed-AppleTalk-Network ]
                     [ Framed-AppleTalk-Zone ]
                     [ Framed-Compression ]
                     [ Framed-Interface-Id ]
                     [ Framed-IP-Address ]
                     [ Framed-IP-Netmask ]
                   * [ Framed-IPv6-Prefix ]
                     [ Framed-IPv6-Pool ]
                   * [ Framed-IPv6-Route ]
                     [ Framed-IPX-Network ]
                     [ Framed-MTU ]
                     [ Framed-Pool ]
                     [ Framed-Protocol ]
                   * [ Framed-Route ]
                     [ Framed-Routing ]
                   * [ Login-IP-Host ]
                   * [ Login-IPv6-Host ]
                     [ Login-LAT-Group ]
                     [ Login-LAT-Node ]
                     [ Login-LAT-Port ]
                     [ Login-LAT-Service ]
                     [ Login-Service ]
                     [ Login-TCP-Port ]
                   * [ Tunneling ]
                   * [ Proxy-Info ]
                   * [ Route-Record ]
                   * [ AVP ]

3.10.  Accounting-Answer (ACA) Command

  The ACA message [BASE] is used to acknowledge an Accounting-Request
  command.  The Accounting-Answer command contains the same Session-Id
  as the Request.  If the Accounting-Request was protected by end-to-
  end security, then the corresponding ACA message MUST be protected as
  well.

  Only the target Diameter Server or home Diameter Server SHOULD
  respond with the Accounting-Answer command.

  Either Acct-Application-Id or Vendor-Specific-Application-Id AVPs
  MUST be present, as it was in the request.



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  The AVPs listed in the Base MUST be assumed to be present, as
  appropriate.  NAS service-specific accounting AVPs SHOULD be present
  as described in section 8 and the rest of this specification.

  Message Format

     <AC-Answer> ::= < Diameter Header: 271, PXY >
                     < Session-Id >
                     { Result-Code }
                     { Origin-Host }
                     { Origin-Realm }
                     { Accounting-Record-Type }
                     { Accounting-Record-Number }
                     [ Acct-Application-Id ]
                     [ Vendor-Specific-Application-Id ]
                     [ User-Name ]
                     [ Accounting-Sub-Session-Id ]
                     [ Acct-Session-Id ]
                     [ Acct-Multi-Session-Id ]
                     [ Event-Timestamp ]
                     [ Error-Message ]
                     [ Error-Reporting-Host ]
                   * [ Failed-AVP ]
                     [ Origin-AAA-Protocol ]
                     [ Origin-State-Id ]
                     [ NAS-Identifier ]
                     [ NAS-IP-Address ]
                     [ NAS-IPv6-Address ]
                     [ NAS-Port ]
                     [ NAS-Port-Id ]
                     [ NAS-Port-Type ]
                     [ Service-Type ]
                     [ Termination-Cause ]
                     [ Accounting-Realtime-Required ]
                     [ Acct-Interim-Interval ]
                   * [ Class ]
                   * [ Proxy-Info ]
                   * [ Route-Record ]
                   * [ AVP ]

4.  NAS Session AVPs

  Diameter reserves the AVP Codes 0 - 255 for RADIUS functions that are
  implemented in Diameter.

  AVPs new to Diameter have code values of 256 and greater.  A Diameter
  message that includes one of these AVPs may represent functions not
  present in the RADIUS environment and may cause interoperability



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RFC 4005       Diameter Network Access Server Application    August 2005


  issues, should the request traverse an AAA system that only supports
  the RADIUS protocol.

  Some RADIUS attributes are not allowed or supported directly in
  Diameter.  See section 9 for more information.

4.1.  Call and Session Information

  This section contains the AVPs specific to NAS Diameter applications
  that are needed to identify the call and session context and status
  information.  On a request, this information allows the server to
  qualify the session.

  These AVPs are used in addition to the Base AVPs of:

     Session-Id
     Auth-Application-Id
     Origin-Host
     Origin-Realm
     Auth-Request-Type
     Termination-Cause

  The following table describes the session level AVPs; their AVP Code
  values, types, and possible flag values; and whether the AVP MAY be
  encrypted.

                                           +---------------------+
                                           |    AVP Flag rules   |
                                           |----+-----+----+-----|----+
                  AVP  Section             |    |     |SHLD| MUST|    |
  Attribute Name  Code Defined  Value Type |MUST| MAY | NOT|  NOT|Encr|
  -----------------------------------------|----+-----+----+-----|----|
  NAS-Port           5   4.2    Unsigned32 | M  |  P  |    |  V  | Y  |
  NAS-Port-Id       87   4.3    UTF8String | M  |  P  |    |  V  | Y  |
  NAS-Port-Type     61   4.4    Enumerated | M  |  P  |    |  V  | Y  |
  Called-Station-Id 30   4.5    UTF8String | M  |  P  |    |  V  | Y  |
  Calling-Station-  31   4.6    UTF8String | M  |  P  |    |  V  | Y  |
    Id                                     |    |     |    |     |    |
  Connect-Info      77   4.7    UTF8String | M  |  P  |    |  V  | Y  |
  Originating-Line- 94   4.8    OctetString|    | M,P |    |  V  | Y  |
    Info                                   |    |     |    |     |    |
  Reply-Message     18   4.9    UTF8String | M  |  P  |    |  V  | Y  |
  -----------------------------------------|----+-----+----+-----|----|








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RFC 4005       Diameter Network Access Server Application    August 2005


4.2.  NAS-Port AVP

  The NAS-Port AVP (AVP Code 5) is of type Unsigned32 and contains the
  physical or virtual port number of the NAS which is authenticating
  the user.  Note that "port" is meant in its sense as a service
  connection on the NAS, not as an IP protocol identifier.

  Either NAS-Port or NAS-Port-Id (AVP Code 87) SHOULD be present in
  AA-Request (AAR) commands if the NAS differentiates among its ports.

4.3.  NAS-Port-Id AVP

  The NAS-Port-Id AVP (AVP Code 87) is of type UTF8String and consists
  of ASCII text identifying the port of the NAS authenticating the
  user.  Note that "port" is meant in its sense as a service connection
  on the NAS, not as an IP protocol identifier.

  Either NAS-Port or NAS-Port-Id SHOULD be present in AA-Request (AAR)
  commands if the NAS differentiates among its ports.  NAS-Port-Id is
  intended for use by NASes that cannot conveniently number their
  ports.

4.4.  NAS-Port-Type AVP

  The NAS-Port-Type AVP (AVP Code 61) is of type Enumerated and
  contains the type of the port on which the NAS is authenticating the
  user.  This AVP SHOULD be present if the NAS uses the same NAS-Port
  number ranges for different service types concurrently.

  The supported values are defined in [RADIUSTypes].  The following
  list is informational and subject to change by the IANA.

      0   Async
      1   Sync
      2   ISDN Sync
      3   ISDN Async V.120
      4   ISDN Async V.110
      5   Virtual
      6   PIAFS
      7   HDLC Clear Channel
      8   X.25
      9   X.75
     10   G.3 Fax
     11   SDSL - Symmetric DSL
     12   ADSL-CAP - Asymmetric DSL, Carrierless Amplitude Phase
             Modulation
     13   ADSL-DMT - Asymmetric DSL, Discrete Multi-Tone
     14   IDSL - ISDN Digital Subscriber Line



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RFC 4005       Diameter Network Access Server Application    August 2005


     15   Ethernet
     16   xDSL - Digital Subscriber Line of unknown type
     17   Cable
     18   Wireless - Other
     19   Wireless - IEEE 802.11
     20   Token-Ring   [RAD802.1X]
     21   FDDI         [RAD802.1X]
     22   Wireless - CDMA2000
     23   Wireless - UMTS
     24   Wireless - 1X-EV
     25   IAPP    [IEEE 802.11f]

4.5.  Called-Station-Id AVP

  The Called-Station-Id AVP (AVP Code 30) is of type UTF8String and
  allows the NAS to send the ASCII string describing the layer 2
  address the user contacted in the request.  For dialup access, this
  can be a phone number obtained by using Dialed Number Identification
  (DNIS) or a similar technology.  Note that this may be different from
  the phone number the call comes in on.  For use with IEEE 802 access,
  the Called-Station-Id MAY contain a MAC address formatted as
  described in [RAD802.1X].  It SHOULD only be present in
  authentication and/or authorization requests.

  If the Auth-Request-Type AVP is set to authorization-only and the
  User-Name AVP is absent, the Diameter Server MAY perform
  authorization based on this field.  This can be used by a NAS to
  request whether a call should be answered based on the DNIS.

  The codification of this field's allowed usage range is outside the
  scope of this specification.

4.6.  Calling-Station-Id AVP

  The Calling-Station-Id AVP (AVP Code 31) is of type UTF8String and
  allows the NAS to send the ASCII string describing the layer 2
  address from which the user connected in the request.  For dialup
  access, this is the phone number the call came from, using Automatic
  Number Identification (ANI) or a similar technology.  For use with
  IEEE 802 access, the Calling-Station-Id AVP MAY contain a MAC
  address, formated as described in [RAD802.1X].  It SHOULD only be
  present in authentication and/or authorization requests.

  If the Auth-Request-Type AVP is set to authorization-only and the
  User-Name AVP is absent, the Diameter Server MAY perform
  authorization based on this field.  This can be used by a NAS to
  request whether a call should be answered based on the layer 2
  address (ANI, MAC Address, etc.)



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RFC 4005       Diameter Network Access Server Application    August 2005


  The codification of this field's allowed usage range is outside the
  scope of this specification.

4.7.  Connect-Info AVP

  The Connect-Info AVP (AVP Code 77) is of type UTF8String and is sent
  in the AA-Request message or ACR STOP message.  When sent in the
  Access-Request, it indicates the nature of the user's connection.
  The connection speed SHOULD be included at the beginning of the first
  Connect-Info AVP in the message.  If the transmit and receive
  connection speeds differ, both may be included in the first AVP with
  the transmit speed listed first (the speed the NAS modem transmits
  at), then a slash (/), then the receive speed, and then other
  optional information.

  For example: "28800 V42BIS/LAPM" or "52000/31200 V90"

  More than one Connect-Info attribute may be present in an
  Accounting-Request packet to accommodate expected efforts by the ITU
  to have modems report more connection information in a standard
  format that might exceed 252 octets.

  If sent in the ACR STOP, this attribute may summarize statistics
  relating to session quality.  For example, in IEEE 802.11, the
  Connect-Info attribute may contain information on the number of link
  layer retransmissions.  The exact format of this attribute is
  implementation specific.

4.8.  Originating-Line-Info AVP

  The Originating-Line-Info AVP (AVP Code 94) is of type OctetString
  and is sent by the NAS system to convey information about the origin
  of the call from an SS7 system.

  The originating line information (OLI) element indicates the nature
  and/or characteristics of the line from which a call originated
  (e.g., pay phone, hotel, cellular).  Telephone companies are starting
  to offer OLI to their customers as an option over Primary Rate
  Interface (PRI).  Internet Service Providers (ISPs) can use OLI in
  addition to Called-Station-Id and Calling-Station-Id attributes to
  differentiate customer calls and to define different services.

  The Value field contains two octets (00 - 99).  ANSI T1.113 and
  BELLCORE 394 can be used for additional information about these
  values and their use.  For more information on current assignment
  values, see [ANITypes].





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RFC 4005       Diameter Network Access Server Application    August 2005


   Value   Description
  ------------------------------------------------------------
     00    Plain Old Telephone Service (POTS)
     01    Multiparty Line (more than 2)
     02    ANI Failure
     03    ANI Observed
     04    ONI Observed
     05    ANI Failure Observed
     06    Station Level Rating
     07    Special Operator Handling Required
     08    InterLATA Restricted
     10    Test Call
     20    Automatic Identified Outward Dialing (AIOD)
     23    Coin or Non-Coin
     24    Toll Free Service (Non-Pay Origination)
     25    Toll Free Service (Pay Origination)
     27    Toll Free Service (Coin Control Origination)
     29    Prison/Inmate Service
     30-32 Intercept
     30    Intercept (Blank)
     31    Intercept (Trouble)
     32    Intercept (Regular)
     34    Telco Operator Handled Call
     40-49 Unrestricted Use
     52    Outward Wide Area Telecommunications Service (OUTWATS)
     60    Telecommunications Relay Service (TRS)(Unrestricted)
     61    Cellular/Wireless PCS (Type 1)
     62    Cellular/Wireless PCS (Type 2)
     63    Cellular/Wireless PCS (Roaming)
     66    TRS (Hotel)
     67    TRS (Restricted)
     70    Pay Station, No Coin Control
     93    Access for Private Virtual Network Service

4.9.  Reply-Message AVP

  The Reply-Message AVP (AVP Code 18) is of type UTF8String and
  contains text that MAY be displayed to the user.  When used in an
  AA-Answer message with a successful Result-Code AVP, it indicates
  success.  When found in an AAA message with a Result-Code other than
  DIAMETER_SUCCESS, the AVP contains a failure message.

  The Reply-Message AVP MAY indicate dialog text to prompt the user
  before another AA-Request attempt.  When used in an AA-Answer with a
  Result-Code of DIAMETER_MULTI_ROUND_AUTH or in an Re-Auth-Request
  message, it MAY contain a dialog text to prompt the user for a
  response.




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RFC 4005       Diameter Network Access Server Application    August 2005


  Multiple Reply-Messages MAY be included, and if any are displayed,
  they MUST be displayed in the same order as they appear in the
  Diameter message.

5.  NAS Authentication AVPs

  This section defines the AVPs necessary to carry the authentication
  information in the Diameter protocol.  The functionality defined here
  provides a RADIUS-like AAA service over a more reliable and secure
  transport, as defined in the base protocol [BASE].

  The following table describes the AVPs; their AVP Code values, types,
  and possible flag values, and whether the AVP MAY be encrypted.

                                           +---------------------+
                                           |    AVP Flag rules   |
                                           |----+-----+----+-----|----+
                  AVP  Section             |    |     |SHLD| MUST|    |
  Attribute Name  Code Defined  Value Type |MUST| MAY | NOT|  NOT|Encr|
  -----------------------------------------|----+-----+----+-----|----|
  User-Password      2   5.1    OctetString| M  |  P  |    |  V  | Y  |
  Password-Retry    75   5.2    Unsigned32 | M  |  P  |    |  V  | Y  |
  Prompt            76   5.3    Enumerated | M  |  P  |    |  V  | Y  |
  CHAP-Auth        402   5.4    Grouped    | M  |  P  |    |  V  | Y  |
  CHAP-Algorithm   403   5.5    Enumerated | M  |  P  |    |  V  | Y  |
  CHAP-Ident       404   5.6    OctetString| M  |  P  |    |  V  | Y  |
  CHAP-Response    405   5.7    OctetString| M  |  P  |    |  V  | Y  |
  CHAP-Challenge    60   5.8    OctetString| M  |  P  |    |  V  | Y  |
  ARAP-Password     70   5.9    OctetString| M  |  P  |    |  V  | Y  |
  ARAP-Challenge-   84   5.10   OctetString| M  |  P  |    |  V  | Y  |
    Response                               |    |     |    |     |    |
  ARAP-Security     73   5.11   Unsigned32 | M  |  P  |    |  V  | Y  |
  ARAP-Security-    74   5.12   OctetString| M  |  P  |    |  V  | Y  |
    Data                                   |    |     |    |     |    |
  -----------------------------------------|----+-----+----+-----|----|

5.1.  User-Password AVP

  The User-Password AVP (AVP Code 2) is of type OctetString and
  contains the password of the user to be authenticated, or the user's
  input in a multi-round authentication exchange.

  The User-Password AVP contains a user password or one-time password
  and therefore represents sensitive information.  As required in
  [BASE], Diameter messages are encrypted by using IPsec or TLS.
  Unless this AVP is used for one-time passwords, the User-Password AVP





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RFC 4005       Diameter Network Access Server Application    August 2005


  SHOULD NOT be used in untrusted proxy environments without encrypting
  it by using end-to-end security techniques, such as the proposed CMS
  Security [DiamCMS].

  The clear-text password (prior to encryption) MUST NOT be longer than
  128 bytes in length.

5.2.  Password-Retry AVP

  The Password-Retry AVP (AVP Code 75) is of type Unsigned32 and MAY be
  included in the AA-Answer if the Result-Code indicates an
  authentication failure.  The value of this AVP indicates how many
  authentication attempts a user is permitted before being
  disconnected.  This AVP is primarily intended for use when the
  Framed-Protocol AVP (see section 6.10.1) is set to ARAP.

5.3.  Prompt AVP

  The Prompt AVP (AVP Code 76) is of type Enumerated and MAY be present
  in the AA-Answer message.  When present, it is used by the NAS to
  determine whether the user's response, when entered, should be
  echoed.

  The supported values are listed in [RADIUSTypes].  The following list
  is informational:

     0  No Echo
     1  Echo

5.4.  CHAP-Auth AVP

  The CHAP-Auth AVP (AVP Code 402) is of type Grouped and contains the
  information necessary to authenticate a user using the PPP
  Challenge-Handshake Authentication Protocol (CHAP) [PPPCHAP].  If the
  CHAP-Auth AVP is found in a message, the CHAP-Challenge AVP MUST be
  present as well.  The optional AVPs containing the CHAP response
  depend upon the value of the CHAP-Algorithm AVP.  The grouped AVP has
  the following ABNF grammar:

     CHAP-Auth  ::= < AVP Header: 402 >
                    { CHAP-Algorithm }
                    { CHAP-Ident }
                    [ CHAP-Response ]
                  * [ AVP ]







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5.5.  CHAP-Algorithm AVP

  The CHAP-Algorithm AVP (AVP Code 403) is of type Enumerated and
  contains the algorithm identifier used in the computation of the CHAP
  response [PPPCHAP].  The following values are currently supported:

     CHAP with MD5       5
        The CHAP response is computed by using the procedure described
        in [PPPCHAP].  This algorithm requires that the CHAP-Response
        AVP MUST be present in the CHAP-Auth AVP.

5.6.  CHAP-Ident AVP

  The CHAP-Ident AVP (AVP Code 404) is of type OctetString and contains
  the 1 octet CHAP Identifier used in the computation of the CHAP
  response [PPPCHAP].

5.7.  CHAP-Response AVP

  The CHAP-Response AVP (AVP Code 405) is of type OctetString and
  contains the 16 octet authentication data provided by the user in
  response to the CHAP challenge [PPPCHAP].

5.8.  CHAP-Challenge AVP

  The CHAP-Challenge AVP (AVP Code 60) is of type OctetString and
  contains the CHAP Challenge sent by the NAS to the CHAP peer
  [PPPCHAP].

5.9.  ARAP-Password AVP

  The ARAP-Password AVP (AVP Code 70) is of type OctetString and is
  only present when the Framed-Protocol AVP (see section 6.10.1) is
  included in the message and is set to ARAP.  This AVP MUST NOT be
  present if either the User-Password or the CHAP-Auth AVP is present.
  See [RADIUSExt] for more information on the contents of this AVP.

5.10.  ARAP-Challenge-Response AVP

  The ARAP-Challenge-Response AVP (AVP Code 84) is of type OctetString
  and is only present when the Framed-Protocol AVP (see section 6.10.1)
  is included in the message and is set to ARAP.  This AVP contains an
  8 octet response to the dial-in client's challenge.  The RADIUS
  server calculates this value by taking the dial-in client's challenge
  from the high-order 8 octets of the ARAP-Password AVP and performing
  DES encryption on this value with the authenticating user's password





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  as the key.  If the user's password is fewer than 8 octets in length,
  the password is padded at the end with NULL octets to a length of 8
  before it is used as a key.

5.11.  ARAP-Security AVP

  The ARAP-Security AVP (AVP Code 73) is of type Unsigned32 and MAY be
  present in the AA-Answer message if the Framed-Protocol AVP (see
  section 6.10.1) is set to the value of ARAP, and the Result-Code AVP
  is set to DIAMETER_MULTI_ROUND_AUTH.  See [RADIUSExt] for more
  information on the format of this AVP.

5.12.  ARAP-Security-Data AVP

  The ARAP-Security AVP (AVP Code 74) is of type OctetString and MAY be
  present in the AA-Request or AA-Answer message if the Framed-Protocol
  AVP is set to the value of ARAP, and the Result-Code AVP is set to
  DIAMETER_MULTI_ROUND_AUTH.  This AVP contains the security module
  challenge or response associated with the ARAP Security Module
  specified in ARAP-Security.

6.  NAS Authorization AVPs

  This section contains the authorization AVPs supported in the NAS
  Application.  The Service-Type AVP SHOULD be present in all messages,
  and, based on its value, additional AVPs defined in this section and
  in section 7 MAY be present.

  Due to space constraints, the short-form IPFltrRule is used to
  represent IPFilterRule, and QoSFltrRule is used for QoSFilterRule.

                                           +---------------------+
                                           |    AVP Flag rules   |
                                           |----+-----+----+-----|----+
                  AVP  Section             |    |     |SHLD| MUST|    |
  Attribute Name  Code Defined  Value Type |MUST| MAY | NOT|  NOT|Encr|
  -----------------------------------------|----+-----+----+-----|----|
  Service-Type       6   6.1    Enumerated | M  |  P  |    |  V  | Y  |
  Callback-Number   19   6.2    UTF8String | M  |  P  |    |  V  | Y  |
  Callback-Id       20   6.3    UTF8String | M  |  P  |    |  V  | Y  |
  Idle-Timeout      28   6.4    Unsigned32 | M  |  P  |    |  V  | Y  |
  Port-Limit        62   6.5    Unsigned32 | M  |  P  |    |  V  | Y  |
  NAS-Filter-Rule  400   6.6    IPFltrRule | M  |  P  |    |  V  | Y  |
  Filter-Id         11   6.7    UTF8String | M  |  P  |    |  V  | Y  |
  Configuration-    78   6.8    OctetString| M  |     |    | P,V |    |
    Token                                  |    |     |    |     |    |
  QoS-Filter-Rule  407   6.9    QoSFltrRule|    |     |    |     |    |
  Framed-Protocol    7  6.10.1  Enumerated | M  |  P  |    |  V  | Y  |



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  Framed-Routing    10  6.10.2  Enumerated | M  |  P  |    |  V  | Y  |
  Framed-MTU        12  6.10.3  Unsigned32 | M  |  P  |    |  V  | Y  |
  Framed-           13  6.10.4  Enumerated | M  |  P  |    |  V  | Y  |
    Compression                            |    |     |    |     |    |
  Framed-IP-Address  8  6.11.1  OctetString| M  |  P  |    |  V  | Y  |
  Framed-IP-Netmask  9  6.11.2  OctetString| M  |  P  |    |  V  | Y  |
  Framed-Route      22  6.11.3  UTF8String | M  |  P  |    |  V  | Y  |
  Framed-Pool       88  6.11.4  OctetString| M  |  P  |    |  V  | Y  |
  Framed-           96  6.11.5  Unsigned64 | M  |  P  |    |  V  | Y  |
    Interface-Id                           |    |     |    |     |    |
  Framed-IPv6-      97  6.11.6  OctetString| M  |  P  |    |  V  | Y  |
    Prefix                                 |    |     |    |     |    |
  Framed-IPv6-      99  6.11.7  UTF8String | M  |  P  |    |  V  | Y  |
    Route                                  |    |     |    |     |    |
  Framed-IPv6-Pool 100  6.11.8  OctetString| M  |  P  |    |  V  | Y  |
  Framed-IPX-       23  6.12.1  UTF8String | M  |  P  |    |  V  | Y  |
    Network                                |    |     |    |     |    |
  Framed-Appletalk- 37  6.13.1  Unsigned32 | M  |  P  |    |  V  | Y  |
    Link                                   |    |     |    |     |    |
  Framed-Appletalk- 38  6.13.2  Unsigned32 | M  |  P  |    |  V  | Y  |
    Network                                |    |     |    |     |    |
  Framed-Appletalk- 39  6.13.3  OctetString| M  |  P  |    |  V  | Y  |
    Zone                                   |    |     |    |     |    |
  ARAP-Features     71  6.14.1  OctetString| M  |  P  |    |  V  | Y  |
  ARAP-Zone-Access  72  6.14.2  Enumerated | M  |  P  |    |  V  | Y  |
  Login-IP-Host     14  6.15.1  OctetString| M  |  P  |    |  V  | Y  |
  Login-IPv6-Host   98  6.15.2  OctetString| M  |  P  |    |  V  | Y  |
  Login-Service     15  6.15.3  Enumerated | M  |  P  |    |  V  | Y  |
  Login-TCP-Port    16  6.16.1  Unsigned32 | M  |  P  |    |  V  | Y  |
  Login-LAT-Service 34  6.17.1  OctetString| M  |  P  |    |  V  | Y  |
  Login-LAT-Node    35  6.17.2  OctetString| M  |  P  |    |  V  | Y  |
  Login-LAT-Group   36  6.17.3  OctetString| M  |  P  |    |  V  | Y  |
  Login-LAT-Port    63  6.17.4  OctetString| M  |  P  |    |  V  | Y  |
  -----------------------------------------|----+-----+----+-----|----|

6.1.  Service-Type AVP

  The Service-Type AVP (AVP Code 6) is of type Enumerated and contains
  the type of service the user has requested or the type of service to
  be provided.  One such AVP MAY be present in an authentication and/or
  authorization request or response.  A NAS is not required to
  implement all of these service types.  It MUST treat unknown or
  unsupported Service-Types received in a response as a failure and end
  the session with a DIAMETER_INVALID_AVP_VALUE Result-Code.

  When used in a request, the Service-Type AVP SHOULD be considered a
  hint to the server that the NAS believes the user would prefer the
  kind of service indicated.  The server is not required to honor the



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  hint.  Furthermore, if the service specified by the server is
  supported, but not compatible with the current mode of access, the
  NAS MUST fail to start the session.  The NAS MUST also generate the
  appropriate error message(s).

  The following values have been defined for the Service-Type AVP.  The
  complete list of defined values can be found in [RADIUS] and
  [RADIUSTypes].  The following list is informational:

      1  Login
      2  Framed
      3  Callback Login
      4  Callback Framed
      5  Outbound
      6  Administrative
      7  NAS Prompt
      8  Authenticate Only
      9  Callback NAS Prompt
     10  Call Check
     11  Callback Administrative
     12  Voice
     13  Fax
     14  Modem Relay
     15  IAPP-Register   [IEEE 802.11f]
     16  IAPP-AP-Check   [IEEE 802.11f]
     17  Authorize Only  [RADDynAuth]

  The following values are further qualified:

     Login               1
        The user should be connected to a host.  The message MAY
        include additional AVPs defined in sections 6.16 or 6.17.

     Framed              2
        A Framed Protocol, such as PPP or SLIP, should be started for
        the User.  The message MAY include additional AVPs defined in
        section 6.10, or section 7 for tunneling services.

     Callback Login      3
        The user should be disconnected and called back, then connected
        to a host.  The message MAY include additional AVPs defined in
        this section.

     Callback Framed     4
        The user should be disconnected and called back, and then a
        Framed Protocol, such as PPP or SLIP, should be started for the
        User.  The message MAY include additional AVPs defined in
        section 6.10, or in section 7 for tunneling services.



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6.2.  Callback-Number AVP

  The Callback-Number AVP (AVP Code 19) is of type UTF8String and
  contains a dialing string to be used for callback.  It MAY be used in
  an authentication and/or authorization request as a hint to the
  server that a Callback service is desired, but the server is not
  required to honor the hint in the corresponding response.

  The codification of this field's allowed usage range is outside the
  scope of this specification.

6.3.  Callback-Id AVP

  The Callback-Id AVP (AVP Code 20) is of type UTF8String and contains
  the name of a place to be called, to be interpreted by the NAS.  This
  AVP MAY be present in an authentication and/or authorization
  response.

  This AVP is not roaming-friendly as it assumes that the Callback-Id
  is configured on the NAS.  Using the Callback-Number AVP therefore
  preferable.

6.4.  Idle-Timeout AVP

  The Idle-Timeout AVP (AVP Code 28) is of type Unsigned32 and sets the
  maximum number of consecutive seconds of idle connection allowable to
  the user before termination of the session or before a prompt is
  issued.  The default is none, or system specific.

6.5.  Port-Limit AVP

  The Port-Limit AVP (AVP Code 62) is of type Unsigned32 and sets the
  maximum number of ports the NAS provides to the user.  It MAY be used
  in an authentication and/or authorization request as a hint to the
  server that multilink PPP [PPPMP] service is desired, but the server
  is not required to honor the hint in the corresponding response.

6.6.  NAS-Filter-Rule AVP

  The NAS-Filter-Rule AVP (AVP Code 400) is of type IPFilterRule and
  provides filter rules that need to be configured on the NAS for the
  user.  One or more of these AVPs MAY be present in an authorization
  response.








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6.7.  Filter-Id AVP

  The Filter-Id AVP (AVP Code 11) is of type UTF8String and contains
  the name of the filter list for this user.  Zero or more Filter-Id
  AVPs MAY be sent in an authorization answer.

  Identifying a filter list by name allows the filter to be used on
  different NASes without regard to filter-list implementation details.
  However, this AVP is not roaming friendly, as filter naming differs
  from one service provider to another.

  In non-RADIUS environments, it is RECOMMENDED that the NAS-Filter-
  Rule AVP be used instead.

6.8.  Configuration-Token AVP

  The Configuration-Token AVP (AVP Code 78) is of type OctetString and
  is sent by a Diameter Server to a Diameter Proxy Agent or Translation
  Agent in an AA-Answer command to indicate a type of user profile to
  be used.  It should not be sent to a Diameter Client (NAS).

  The format of the Data field of this AVP is site specific.

6.9.  QoS-Filter-Rule AVP

  The QoS-Filter-Rule AVP (AVP Code 407) is of type QoSFilterRule and
  provides QoS filter rules that need to be configured on the NAS for
  the user.  One or more such AVPs MAY be present in an authorization
  response.

  Note: Due to an editorial mistake in [BASE], only the AVP format is
  discussed.  The complete QoSFilterRule definition was not included.
  It is reprinted here for clarification.

  QoSFilterRule

     The QosFilterRule format is derived from the OctetString AVP Base
     Format.  It uses the ASCII charset.  Packets may be marked or
     metered based on the following information:

        Direction                          (in or out)
        Source and destination IP address  (possibly masked)
        Protocol
        Source and destination port        (lists or ranges)
        DSCP values                        (no mask or range)

     Rules for the appropriate direction are evaluated in order; the
     first matched rule terminates the evaluation.  Each packet is



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     evaluated once.  If no rule matches, the packet is treated as best
     effort.  An access device unable to interpret or apply a QoS rule
     SHOULD NOT terminate the session.

  QoSFilterRule filters MUST follow the following format:

     action dir proto from src to dst [options]

               tag    - Mark packet with a specific DSCP
                        [DIFFSERV].  The DSCP option MUST be
                        included.
               meter  - Meter traffic.  The metering options
                        MUST be included.

  dir           The format is as described under IPFilterRule.

  proto         The format is as described under IPFilterRule.

  src and dst   The format is as described under IPFilterRule.

        options:

        DSCP <color>
              Color values as defined in [DIFFSERV].  Exact
              matching of DSCP values is required (no masks or
              ranges).

        metering <rate> <color_under> <color_over>
              The metering option provides Assured Forwarding,
              as defined in [DIFFSERVAF], and MUST be present
              if the action is set to meter.  The rate option is
              the throughput, in bits per second, used
              by the access device to mark packets.  Traffic
              over the rate is marked with the color_over
              codepoint, and traffic under the rate is marked
              with the color_under codepoint.  The color_under
              and color_over options contain the drop
              preferences and MUST conform to the recommended
              codepoint keywords described in [DIFFSERVAF]
              (e.g., AF13).

              The metering option also supports the strict
              limit on traffic required by Expedited
              Forwarding, as defined in [DIFFSERVEF].  The
              color_over option may contain the keyword "drop"
              to prevent forwarding of traffic that exceeds the
              rate parameter.




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        The rule syntax is a modified subset of ipfw(8) from FreeBSD,
        and the ipfw.c code may provide a useful base for
        implementations.

6.10.  Framed Access Authorization AVPs

  This section lists the authorization AVPs necessary to
  support framed access, such as PPP and SLIP.  AVPs defined in this
  section MAY be present in a message if the Service-Type AVP was set
  to "Framed" or "Callback Framed".

6.10.1.  Framed-Protocol AVP

  The Framed-Protocol AVP (AVP Code 7) is of type Enumerated and
  contains the framing to be used for framed access.  This AVP MAY be
  present in both requests and responses.  The supported values are
  listed in [RADIUSTypes].  The following list is informational:

     1  PPP
     2  SLIP
     3  AppleTalk Remote Access Protocol (ARAP)
     4  Gandalf proprietary SingleLink/MultiLink protocol
     5  Xylogics proprietary IPX/SLIP
     6  X.75 Synchronous

6.10.2.  Framed-Routing AVP

  The Framed-Routing AVP (AVP Code 10) is of type Enumerated and
  contains the routing method for the user when the user is a router to
  a network.  This AVP SHOULD only be present in authorization
  responses.  The supported values are listed in [RADIUSTypes].  The
  following list is informational:

     0  None
     1  Send routing packets
     2  Listen for routing packets
     3  Send and Listen

6.10.3.  Framed-MTU AVP

  The Framed-MTU AVP (AVP Code 12) is of type Unsigned32 and contains
  the Maximum Transmission Unit to be configured for the user, when it
  is not negotiated by some other means (such as PPP).  This AVP SHOULD
  only be present in authorization responses.  The MTU value MUST be in
  the range from 64 to 65535.






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6.10.4.  Framed-Compression AVP

  The Framed-Compression AVP (AVP Code 13) is of type Enumerated and
  contains the compression protocol to be used for the link.  It MAY be
  used in an authorization request as a hint to the server that a
  specific compression type is desired, but the server is not required
  to honor the hint in the corresponding response.

  More than one compression protocol AVP MAY be sent.  The NAS is
  responsible for applying the proper compression protocol to the
  appropriate link traffic.

  The supported values are listed in [RADIUSTypes].  The following list
  is informational:

     0  None
     1  VJ TCP/IP header compression
     2  IPX header compression
     3  Stac-LZS compression

6.11.  IP Access Authorization AVPs

  The AVPs defined in this section are used when the user requests, or
  is being granted, access service to IP.

6.11.1.  Framed-IP-Address AVP

  The Framed-IP-Address AVP (AVP Code 8) [RADIUS] is of type
  OctetString and contains an IPv4 address of the type specified in the
  attribute value to be configured for the user.  It MAY be used in an
  authorization request as a hint to the server that a specific address
  is desired, but the server is not required to honor the hint in the
  corresponding response.

  Two values have special significance: 0xFFFFFFFF and 0xFFFFFFFE.  The
  value 0xFFFFFFFF indicates that the NAS should allow the user to
  select an address (i.e., negotiated).  The value 0xFFFFFFFE indicates
  that the NAS should select an address for the user (e.g., assigned
  from a pool of addresses kept by the NAS).

6.11.2.  Framed-IP-Netmask AVP

  The Framed-IP-Netmask AVP (AVP Code 9) is of type OctetString and
  contains the four octets of the IPv4 netmask to be configured for the
  user when the user is a router to a network.  It MAY be used in an
  authorization request as a hint to the server that a specific netmask





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  is desired, but the server is not required to honor the hint in the
  corresponding response.  This AVP MUST be present in a response if
  the request included this AVP with a value of 0xFFFFFFFF.

6.11.3.  Framed-Route AVP

  The Framed-Route AVP (AVP Code 22) is of type UTF8String and contains
  the ASCII routing information to be configured for the user on the
  NAS.  Zero or more of these AVPs MAY be present in an authorization
  response.

  The string MUST contain a destination prefix in dotted quad form
  optionally followed by a slash and a decimal length specifier stating
  how many high-order bits of the prefix should be used.  This is
  followed by a space, a gateway address in dotted quad form, a space,
  and one or more metrics separated by spaces; for example,

     "192.168.1.0/24 192.168.1.1 1".

  The length specifier may be omitted, in which case it should default
  to 8 bits for class A prefixes, to 16 bits for class B prefixes, and
  to 24 bits for class C prefixes; for example,

     "192.168.1.0 192.168.1.1 1".

  Whenever the gateway address is specified as "0.0.0.0" the IP address
  of the user SHOULD be used as the gateway address.

6.11.4.  Framed-Pool AVP

  The Framed-Pool AVP (AVP Code 88) is of type OctetString and contains
  the name of an assigned address pool that SHOULD be used to assign an
  address for the user.  If a NAS does not support multiple address
  pools, the NAS SHOULD ignore this AVP.  Address pools are usually
  used for IP addresses but can be used for other protocols if the NAS
  supports pools for those protocols.

  Although specified as type OctetString for compatibility with RADIUS
  [RADIUSExt], the encoding of the Data field SHOULD also conform to
  the rules for the UTF8String Data Format.

6.11.5.  Framed-Interface-Id AVP

  The Framed-Interface-Id AVP (AVP Code 96) is of type Unsigned64 and
  contains the IPv6 interface identifier to be configured for the user.
  It MAY be used in authorization requests as a hint to the server that
  a specific interface id is desired, but the server is not required to
  honor the hint in the corresponding response.



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6.11.6.  Framed-IPv6-Prefix AVP

  The Framed-IPv6-Prefix AVP (AVP Code 97) is of type OctetString and
  contains the IPv6 prefix to be configured for the user.  One or more
  AVPs MAY be used in authorization requests as a hint to the server
  that specific IPv6 prefixes are desired, but the server is not
  required to honor the hint in the corresponding response.

6.11.7.  Framed-IPv6-Route AVP

  The Framed-IPv6-Route AVP (AVP Code 99) is of type UTF8String and
  contains the ASCII routing information to be configured for the user
  on the NAS.  Zero or more of these AVPs MAY be present in an
  authorization response.

  The string MUST contain an IPv6 address prefix followed by a slash
  and a decimal length specifier stating how many high order bits of
  the prefix should be used.  This is followed by a space, a gateway
  address in hexadecimal notation, a space, and one or more metrics
  separated by spaces; for example,

     "2000:0:0:106::/64 2000::106:a00:20ff:fe99:a998 1".

  Whenever the gateway address is the IPv6 unspecified address, the IP
  address of the user SHOULD be used as the gateway address, such as
  in:

     "2000:0:0:106::/64 :: 1".

6.11.8.  Framed-IPv6-Pool AVP

  The Framed-IPv6-Pool AVP (AVP Code 100) is of type OctetString and
  contains the name of an assigned pool that SHOULD be used to assign
  an IPv6 prefix for the user.  If the access device does not support
  multiple prefix pools, it MUST ignore this AVP.

  Although specified as type OctetString for compatibility with RADIUS
  [RADIUSIPv6], the encoding of the Data field SHOULD also conform to
  the rules for the UTF8String Data Format.

6.12.  IPX Access

  The AVPs defined in this section are used when the user requests, or
  is being granted, access to an IPX network service.







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6.12.1.  Framed-IPX-Network AVP

  The Framed-IPX-Network AVP (AVP Code 23) is of type Unsigned32 and
  contains the IPX Network number to be configured for the user.  It
  MAY be used in an authorization request as a hint to the server that
  a specific address is desired, but the server is not required to
  honor the hint in the corresponding response.

  Two addresses have special significance: 0xFFFFFFFF and 0xFFFFFFFE.
  The value 0xFFFFFFFF indicates that the NAS should allow the user to
  select an address (i.e., Negotiated).  The value 0xFFFFFFFE indicates
  that the NAS should select an address for the user (e.g., assign it
  from a pool of one or more IPX networks kept by the NAS).

6.13.  AppleTalk Network Access

  The AVPs defined in this section are used when the user requests, or
  is being granted, access to an AppleTalk network [AppleTalk].

6.13.1.  Framed-AppleTalk-Link AVP

  The Framed-AppleTalk-Link AVP (AVP Code 37) is of type Unsigned32 and
  contains the AppleTalk network number that should be used for the
  serial link to the user, which is another AppleTalk router.  This AVP
  MUST only be present in an authorization response and is never used
  when the user is not another router.

  Despite the size of the field, values range from 0 to 65,535.  The
  special value of 0 indicates an unnumbered serial link.  A value of 1
  to 65,535 means that the serial line between the NAS and the user
  should be assigned that value as an AppleTalk network number.

6.13.2.  Framed-AppleTalk-Network AVP

  The Framed-AppleTalk-Network AVP (AVP Code 38) is of type Unsigned32
  and contains the AppleTalk Network number that the NAS should probe
  to allocate an AppleTalk node for the user.  This AVP MUST only be
  present in an authorization response and is never used when the user
  is not another router.  Multiple instances of this AVP indicate that
  the NAS may probe, using any of the network numbers specified.

  Despite the size of the field, values range from 0 to 65,535.  The
  special value 0 indicates that the NAS should assign a network for
  the user, using its default cable range.  A value between 1 and
  65,535 (inclusive) indicates to the AppleTalk Network that the NAS
  should probe to find an address for the user.





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6.13.3.  Framed-AppleTalk-Zone AVP

  The Framed-AppleTalk-Zone AVP (AVP Code 39) is of type OctetString
  and contains the AppleTalk Default Zone to be used for this user.
  This AVP MUST only be present in an authorization response.  Multiple
  instances of this AVP in the same message are not allowed.

  The codification of this field's allowed range is outside the scope
  of this specification.

6.14.  AppleTalk Remote Access

  The AVPs defined in this section are used when the user requests, or
  is being granted, access to the AppleTalk network via the AppleTalk
  Remote Access Protocol [ARAP].  They are only present if the Framed-
  Protocol AVP (see section 6.10.1) is set to ARAP.  Section 2.2 of RFC
  2869 [RADIUSExt] describes the operational use of these attributes.

6.14.1.  ARAP-Features AVP

  The ARAP-Features AVP (AVP Code 71) is of type OctetString and MAY be
  present in the AA-Accept message if the Framed-Protocol AVP is set to
  the value of ARAP.  See [RADIUSExt] for more information about the
  format of this AVP.

6.14.2.  ARAP-Zone-Access AVP

  The ARAP-Zone-Access AVP (AVP Code 72) is of type Enumerated and MAY
  be present in the AA-Accept message if the Framed-Protocol AVP is set
  to the value of ARAP.

  The supported values are listed in [RADIUSTypes] and defined in
  [RADIUSExt].

6.15.  Non-Framed Access Authorization AVPs

  This section contains the authorization AVPs that are needed to
  support terminal server functionality.  AVPs defined in this section
  MAY be present in a message if the Service-Type AVP was set to
  "Login" or "Callback Login".

6.15.1.  Login-IP-Host AVP

  The Login-IP-Host AVP (AVP Code 14) [RADIUS] is of type OctetString
  and contains the IPv4 address of a host with which to connect the
  user when the Login-Service AVP is included.  It MAY be used in an
  AA-Request command as a hint to the Diameter Server that a specific




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  host is desired, but the Diameter Server is not required to honor the
  hint in the AA-Answer.

  Two addresses have special significance: all ones and 0.  The value
  of all ones indicates that the NAS SHOULD allow the user to select an
  address.  The value 0 indicates that the NAS SHOULD select a host to
  connect the user to.

6.15.2.  Login-IPv6-Host AVP

  The Login-IPv6-Host AVP (AVP Code 98) [RADIUSIPv6] is of type
  OctetString and contains the IPv6 address of a host with which to
  connect the user when the Login-Service AVP is included.  It MAY be
  used in an AA-Request command as a hint to the Diameter Server that a
  specific host is desired, but the Diameter Server is not required to
  honor the hint in the AA-Answer.

  Two addresses have special significance:

  0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF and 0.  The value
  0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF indicates that the NAS SHOULD
  allow the user to select an address.  The value 0 indicates that the
  NAS SHOULD select a host to connect the user to.

6.15.3.  Login-Service AVP

  The Login-Service AVP (AVP Code 15) is of type Enumerated and
  contains the service that should be used to connect the user to the
  login host.  This AVP SHOULD only be present in authorization
  responses.

  The supported values are listed in [RADIUSTypes].  The following list
  is informational:

     0  Telnet
     1  Rlogin
     2  TCP Clear
     3  PortMaster (proprietary)
     4  LAT
     5  X25-PAD
     6  X25-T3POS
     8  TCP Clear Quiet (suppresses any NAS-generated connect
                 string)








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6.16.  TCP Services

  The AVPs described in this section MAY be present if the Login-
  Service AVP is set to Telnet, Rlogin, TCP Clear, or TCP Clear Quiet.

6.16.1.  Login-TCP-Port AVP

  The Login-TCP-Port AVP (AVP Code 16) is of type Unsigned32 and
  contains the TCP port with which the user is to be connected when the
  Login-Service AVP is also present.  This AVP SHOULD only be present
  in authorization responses.  The value MUST NOT be greater than
  65,535.

6.17.  LAT Services

  The AVPs described in this section MAY be present if the Login-
  Service AVP is set to LAT [LAT].

6.17.1.  Login-LAT-Service AVP

  The Login-LAT-Service AVP (AVP Code 34) is of type OctetString and
  contains the system with which the user is to be connected by LAT.
  It MAY be used in an authorization request as a hint to the server
  that a specific service is desired, but the server is not required to
  honor the hint in the corresponding response.  This AVP MUST only be
  present in the response if the Login-Service AVP states that LAT is
  desired.

  Administrators use this service attribute when dealing with clustered
  systems, such as a VAX or Alpha cluster.  In these environments,
  several different time-sharing hosts share the same resources (disks,
  printers, etc.), and administrators often configure each host to
  offer access (service) to each of the shared resources.  In this
  case, each host in the cluster advertises its services through LAT
  broadcasts.

  Sophisticated users often know which service providers (machines) are
  faster and tend to use a node name when initiating a LAT connection.
  Some administrators want particular users to use certain machines as
  a primitive form of load balancing (although LAT knows how to do load
  balancing itself).

  The String field contains the identity of the LAT service to use.
  The LAT Architecture allows this string to contain $ (dollar), -
  (hyphen), . (period), _ (underscore), numerics, upper- and lowercase
  alphabetics, and the ISO Latin-1 character set extension [ISOLatin].
  All LAT string comparisons are case insensitive.




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6.17.2.  Login-LAT-Node AVP

  The Login-LAT-Node AVP (AVP Code 35) is of type OctetString and
  contains the Node with which the user is to be automatically
  connected by LAT.  It MAY be used in an authorization request as a
  hint to the server that a specific LAT node is desired, but the
  server is not required to honor the hint in the corresponding
  response.  This AVP MUST only be present in a response if the Login-
  Service-Type AVP is set to LAT.

  The String field contains the identity of the LAT service to use.
  The LAT Architecture allows this string to contain $ (dollar), -
  (hyphen), . (period), _ (underscore), numerics, upper- and lowercase
  alphabetics, and the ISO Latin-1 character set extension [ISOLatin].
  All LAT string comparisons are case insensitive.

6.17.3.  Login-LAT-Group AVP

  The Login-LAT-Group AVP (AVP Code 36) is of type OctetString and
  contains a string identifying the LAT group codes this user is
  authorized to use.  It MAY be used in an authorization request as a
  hint to the server that a specific group is desired, but the server
  is not required to honor the hint in the corresponding response.
  This AVP MUST only be present in a response if the Login-Service-Type
  AVP is set to LAT.

  LAT supports 256 different group codes, which LAT uses as a form of
  access rights.  LAT encodes the group codes as a 256-bit bitmap.

  Administrators can assign one or more of the group code bits at the
  LAT service provider; it will only accept LAT connections that have
  these group codes set in the bitmap.  The administrators assign a
  bitmap of authorized group codes to each user.  LAT gets these from
  the operating system and uses them in its requests to the service
  providers.

  The codification of the range of allowed usage of this field is
  outside the scope of this specification.

6.17.4.  Login-LAT-Port AVP

  The Login-LAT-Port AVP (AVP Code 63) is of type OctetString and
  contains the Port with which the user is to be connected by LAT.  It
  MAY be used in an authorization request as a hint to the server that
  a specific port is desired, but the server is not required to honor
  the hint in the corresponding response.  This AVP MUST only be
  present in a response if the Login-Service-Type AVP is set to LAT.




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  The String field contains the identity of the LAT service to use.
  The LAT Architecture allows this string to contain $ (dollar), -
  (hyphen), . (period), _ (underscore), numerics, upper- and lower-case
  alphabetics, and the ISO Latin-1 character set extension [ISOLatin].
  All LAT string comparisons are case insensitive.

7.  NAS Tunneling

  Some NASes support compulsory tunnel services in which the incoming
  connection data is conveyed by an encapsulation method to a gateway
  elsewhere in the network.  This is typically transparent to the
  service user, and the tunnel characteristics may be described by the
  remote AAA server, based on the user's authorization information.
  Several tunnel characteristics may be returned, and the NAS
  implementation may choose one [RADTunnels], [RADTunlAcct].

                                           +---------------------+
                                           |    AVP Flag rules   |
                                           |----+-----+----+-----|----+
                  AVP  Section             |    |     |SHLD| MUST|    |
  Attribute Name  Code Defined  Value Type |MUST| MAY | NOT| NOT |Encr|
  -----------------------------------------|----+-----+----+-----|----|
  Tunneling        401   7.1    Grouped    | M  |  P  |    |  V  | N  |
  Tunnel-Type       64   7.2    Enumerated | M  |  P  |    |  V  | Y  |
  Tunnel-Medium-    65   7.3    Enumerated | M  |  P  |    |  V  | Y  |
    Type                                   |    |     |    |     |    |
  Tunnel-Client-    66   7.4    UTF8String | M  |  P  |    |  V  | Y  |
    Endpoint                               |    |     |    |     |    |
  Tunnel-Server-    67   7.5    UTF8String | M  |  P  |    |  V  | Y  |
    Endpoint                               |    |     |    |     |    |
  Tunnel-Password   69   7.6    OctetString| M  |  P  |    |  V  | Y  |
  Tunnel-Private-   81   7.7    OctetString| M  |  P  |    |  V  | Y  |
    Group-Id                               |    |     |    |     |    |
  Tunnel-           82   7.8    OctetString| M  |  P  |    |  V  | Y  |
    Assignment-Id                          |    |     |    |     |    |
  Tunnel-Preference 83   7.9    Unsigned32 | M  |  P  |    |  V  | Y  |
  Tunnel-Client-    90   7.10   UTF8String | M  |  P  |    |  V  | Y  |
    Auth-Id                                |    |     |    |     |    |
  Tunnel-Server-    91   7.11   UTF8String | M  |  P  |    |  V  | Y  |
    Auth-Id                                |    |     |    |     |    |
  -----------------------------------------|----+-----+----+-----|----|

7.1.  Tunneling AVP

  The Tunneling AVP (AVP Code 401) is of type Grouped and contains the
  following AVPs, used to describe a compulsory tunnel service:
  [RADTunnels], [RADTunlAcct].  Its data field has the following ABNF
  grammar:



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     Tunneling     ::= < AVP Header: 401 >
                       { Tunnel-Type }
                       { Tunnel-Medium-Type }
                       { Tunnel-Client-Endpoint }
                       { Tunnel-Server-Endpoint }
                       [ Tunnel-Preference ]
                       [ Tunnel-Client-Auth-Id ]
                       [ Tunnel-Server-Auth-Id ]
                       [ Tunnel-Assignment-Id ]
                       [ Tunnel-Password ]
                       [ Tunnel-Private-Group-Id ]

7.2.  Tunnel-Type AVP

  The Tunnel-Type AVP (AVP Code 64) is of type Enumerated and contains
  the tunneling protocol(s) to be used (in the case of a tunnel
  initiator) or in use (in the case of a tunnel terminator).  It MAY be
  used in an authorization request as a hint to the server that a
  specific tunnel type is desired, but the server is not required to
  honor the hint in the corresponding response.

  The Tunnel-Type AVP SHOULD also be included in Accounting-Request
  messages.

  A tunnel initiator is not required to implement any of these tunnel
  types.  If a tunnel initiator receives a response that contains only
  unknown or unsupported Tunnel-Types, the tunnel initiator MUST behave
  as though a response were received with the Result-Code indicating a
  failure.

  The supported values are listed in [RADIUSTypes].  The following list
  is informational:

      1  Point-to-Point Tunneling Protocol (PPTP)
      2  Layer Two Forwarding (L2F)
      3  Layer Two Tunneling Protocol (L2TP)
      4  Ascend Tunnel Management Protocol (ATMP)
      5  Virtual Tunneling Protocol (VTP)
      6  IP Authentication Header in the Tunnel-mode (AH)
      7  IP-in-IP Encapsulation (IP-IP)
      8  Minimal IP-in-IP Encapsulation (MIN-IP-IP)
      9  IP Encapsulating Security Payload in the Tunnel-mode (ESP)
     10  Generic Route Encapsulation (GRE)
     11  Bay Dial Virtual Services (DVS)
     12  IP-in-IP Tunneling
     13  Virtual LANs (VLAN)





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7.3.  Tunnel-Medium-Type AVP

  The Tunnel-Medium-Type AVP (AVP Code 65) is of type Enumerated and
  contains the transport medium to use when creating a tunnel for
  protocols (such as L2TP) that can operate over multiple transports.
  It MAY be used in an authorization request as a hint to the server
  that a specific medium is desired, but the server is not required to
  honor the hint in the corresponding response.

  The supported values are listed in [RADIUSTypes].  The following list
  is informational:

      1  IPv4 (IP version 4)
      2  IPv6 (IP version 6)
      3  NSAP
      4  HDLC (8-bit multidrop)
      5  BBN 1822
      6  802 (includes all 802 media plus Ethernet "canonical
                   format")
      7  E.163 (POTS)
      8  E.164 (SMDS, Frame Relay, ATM)
      9  F.69 (Telex)
     10  X.121 (X.25, Frame Relay)
     11  IPX
     12  Appletalk
     13  Decnet IV
     14  Banyan Vines
     15  E.164 with NSAP format subaddress

7.4.  Tunnel-Client-Endpoint AVP

  The Tunnel-Client-Endpoint AVP (AVP Code 66) is of type UTF8String
  and contains the address of the initiator end of the tunnel.  It MAY
  be used in an authorization request as a hint to the server that a
  specific endpoint is desired, but the server is not required to honor
  the hint in the corresponding response.

  This AVP SHOULD be included in the corresponding Accounting-Request
  messages, in which case it indicates the address from which the
  tunnel was initiated.  This AVP, along with the Tunnel-Server-
  Endpoint and Session-Id AVP [BASE], MAY be used to provide a globally
  unique means to identify a tunnel for accounting and auditing
  purposes.

  If Tunnel-Medium-Type is IPv4 (1), then this string is either the
  fully qualified domain name (FQDN) of the tunnel client machine, or a





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  "dotted-decimal" IP address.  Implementations MUST support the
  dotted-decimal format and SHOULD support the FQDN format for IP
  addresses.

  If Tunnel-Medium-Type is IPv6 (2), then this string is either the
  FQDN of the tunnel client machine, or a text representation of the
  address in either the preferred or alternate form [IPv6Addr].
  Conforming implementations MUST support the preferred form and SHOULD
  support both the alternate text form and the FQDN format for IPv6
  addresses.

  If Tunnel-Medium-Type is neither IPv4 nor IPv6, then this string is a
  tag referring to configuration data local to the Diameter client that
  describes the interface or medium-specific client address to use.

7.5.  Tunnel-Server-Endpoint AVP

  The Tunnel-Server-Endpoint AVP (AVP Code 67) is of type UTF8String
  and contains the address of the server end of the tunnel.  It MAY be
  used in an authorization request as a hint to the server that a
  specific endpoint is desired, but the server is not required to honor
  the hint in the corresponding response.

  This AVP SHOULD be included in the corresponding Accounting-Request
  messages, in which case it indicates the address from which the
  tunnel was initiated.  This AVP, along with the Tunnel-Client-
  Endpoint and Session-Id AVP [BASE], MAY be used to provide a globally
  unique means to identify a tunnel for accounting and auditing
  purposes.

  If Tunnel-Medium-Type is IPv4 (1), then this string is either the
  fully qualified domain name (FQDN) of the tunnel server machine, or a
  "dotted-decimal" IP address.  Implementations MUST support the
  dotted-decimal format and SHOULD support the FQDN format for IP
  addresses.

  If Tunnel-Medium-Type is IPv6 (2), then this string is either the
  FQDN of the tunnel server machine, or a text representation of the
  address in either the preferred or alternate form [IPv6Addr].
  Implementations MUST support the preferred form and SHOULD support
  both the alternate text form and the FQDN format for IPv6 addresses.

  If Tunnel-Medium-Type is not IPv4 or IPv6, this string is a tag
  referring to configuration data local to the Diameter client that
  describes the interface or medium-specific server address to use.






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7.6.  Tunnel-Password AVP

  The Tunnel-Password AVP (AVP Code 69) is of type OctetString and may
  contain a password to be used to authenticate to a remote server.
  The Tunnel-Password AVP contains sensitive information.  This value
  is not protected in the same manner as RADIUS [RADTunnels].

  As required in [BASE], Diameter messages are encrypted by using IPsec
  or TLS.  The Tunnel-Password AVP SHOULD NOT be used in untrusted
  proxy environments without encrypting it by using end-to-end security
  techniques, such as CMS Security [DiamCMS].

7.7.  Tunnel-Private-Group-Id AVP

  The Tunnel-Private-Group-Id AVP (AVP Code 81) is of type OctetString
  and contains the group Id for a particular tunneled session.  The
  Tunnel-Private-Group-Id AVP MAY be included in an authorization
  request if the tunnel initiator can predetermine the group resulting
  from a particular connection.  It SHOULD be included in the
  authorization response if this tunnel session is to be treated as
  belonging to a particular private group.  Private groups may be used
  to associate a tunneled session with a particular group of users.
  For example, it MAY be used to facilitate routing of unregistered IP
  addresses through a particular interface.  This AVP SHOULD be
  included in the Accounting-Request messages that pertain to the
  tunneled session.

7.8.  Tunnel-Assignment-Id AVP

  The Tunnel-Assignment-Id AVP (AVP Code 82) is of type OctetString and
  is used to indicate to the tunnel initiator the particular tunnel to
  which a session is to be assigned.  Some tunneling protocols, such as
  [PPTP] and [L2TP], allow for sessions between the same two tunnel
  endpoints to be multiplexed over the same tunnel and also for a given
  session to use its own dedicated tunnel.  This attribute provides a
  mechanism for Diameter to inform the tunnel initiator (e.g., PAC,
  LAC) whether to assign the session to a multiplexed tunnel or to a
  separate tunnel.  Furthermore, it allows for sessions sharing
  multiplexed tunnels to be assigned to different multiplexed tunnels.

  A particular tunneling implementation may assign differing
  characteristics to particular tunnels.  For example, different
  tunnels may be assigned different QoS parameters.  Such tunnels may
  be used to carry either individual or multiple sessions.  The
  Tunnel-Assignment-Id attribute thus allows the Diameter server to
  indicate that a particular session is to be assigned to a tunnel
  providing an appropriate level of service.  It is expected that any
  QoS-related Diameter tunneling attributes defined in the future



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  accompanying this one will be associated by the tunnel initiator with
  the Id given by this attribute.  In the meantime, any semantic given
  to a particular Id string is a matter left to local configuration in
  the tunnel initiator.

  The Tunnel-Assignment-Id AVP is of significance only to Diameter and
  the tunnel initiator.  The Id it specifies is only intended to be of
  local use to Diameter and the tunnel initiator.  The Id assigned by
  the tunnel initiator is not conveyed to the tunnel peer.

  This attribute MAY be included in authorization responses.  The
  tunnel initiator receiving this attribute MAY choose to ignore it and
  to assign the session to an arbitrary multiplexed or non-multiplexed
  tunnel between the desired endpoints.  This AVP SHOULD also be
  included in the Accounting-Request messages pertaining to the
  tunneled session.

  If a tunnel initiator supports the Tunnel-Assignment-Id AVP, then it
  should assign a session to a tunnel in the following manner:

     -  If this AVP is present and a tunnel exists between the
        specified endpoints with the specified Id, then the session
        should be assigned to that tunnel.

     -  If this AVP is present and no tunnel exists between the
        specified endpoints with the specified Id, then a new tunnel
        should be established for the session and the specified Id
        should be associated with the new tunnel.

     -  If this AVP is not present, then the session is assigned to an
        unnamed tunnel.  If an unnamed tunnel does not yet exist
        between the specified endpoints, then it is established and
        used for this session and for subsequent ones established
        without the Tunnel-Assignment-Id attribute.  A tunnel initiator
        MUST NOT assign a session for which a Tunnel-Assignment-Id AVP
        was not specified to a named tunnel (i.e., one that was
        initiated by a session specifying this AVP).

  Note that the same Id may be used to name different tunnels if these
  tunnels are between different endpoints.

7.9.  Tunnel-Preference AVP

  The Tunnel-Preference AVP (AVP Code 83) is of type Unsigned32 and is
  used to identify the relative preference assigned to each tunnel when
  more than one set of tunneling AVPs is returned within separate
  Grouped-AVP AVPs.  It MAY be used in an authorization request as a
  hint to the server that a specific preference is desired, but the



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  server is not required to honor the hint in the corresponding
  response.

  For example, suppose that AVPs describing two tunnels are returned by
  the server, one with a Tunnel-Type of PPTP and the other with a
  Tunnel-Type of L2TP.  If the tunnel initiator supports only one of
  the Tunnel-Types returned, it will initiate a tunnel of that type.
  If, however, it supports both tunnel protocols, it SHOULD use the
  value of the Tunnel-Preference AVP to decide which tunnel should be
  started.  The tunnel with the lowest numerical value in the Value
  field of this AVP SHOULD be given the highest preference.  The values
  assigned to two or more instances of the Tunnel-Preference AVP within
  a given authorization response MAY be identical.  In this case, the
  tunnel initiator SHOULD use locally configured metrics to decide
  which set of AVPs to use.

7.10.  Tunnel-Client-Auth-Id AVP

  The Tunnel-Client-Auth-Id AVP (AVP Code 90) is of type UTF8String and
  specifies the name used by the tunnel initiator during the
  authentication phase of tunnel establishment.  It MAY be used in an
  authorization request as a hint to the server that a specific
  preference is desired, but the server is not required to honor the
  hint in the corresponding response.  This AVP MUST be present in the
  authorization response if an authentication name other than the
  default is desired.  This AVP SHOULD be included in the Accounting-
  Request messages pertaining to the tunneled session.

7.11.  Tunnel-Server-Auth-Id AVP

  The Tunnel-Server-Auth-Id AVP (AVP Code 91) is of type UTF8String and
  specifies the name used by the tunnel terminator during the
  authentication phase of tunnel establishment.  It MAY be used in an
  authorization request as a hint to the server that a specific
  preference is desired, but the server is not required to honor the
  hint in the corresponding response.  This AVP MUST be present in the
  authorization response if an authentication name other than the
  default is desired.  This AVP SHOULD be included in the Accounting-
  Request messages pertaining to the tunneled session.

8.  NAS Accounting

  Applications implementing this specification use Diameter Accounting,
  as defined in [BASE], and the AVPs in the following section.
  Service-specific AVP usage is defined in the tables in section 10.

  If accounting is active, Accounting Request (ACR) messages SHOULD be
  sent after the completion of any Authentication or Authorization



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  transaction and at the end of a Session.  The Accounting-Record-Type
  value indicates the type of event.  All other AVPs identify the
  session and provide additional information relevant to the event.

  The successful completion of the first Authentication or
  Authorization transaction SHOULD cause a START_RECORD to be sent.  If
  additional Authentications or Authorizations occur in later
  transactions, the first exchange should generate a START_RECORD, and
  the later an INTERIM_RECORD.  For a given session, there MUST only be
  one set of matching START and STOP records, with any number of
  INTERIM_RECORDS in between, or one EVENT_RECORD indicating the reason
  a session wasn't started.

  The following table describes the AVPs; their AVP Code values, types,
  and possible flag values; and whether the AVP MAY be encrypted.

                                           +---------------------+
                                           |    AVP Flag rules   |
                                           |----+-----+----+-----|----+
                  AVP  Section             |    |     |SHLD| MUST|    |
  Attribute Name  Code Defined  Value Type |MUST| MAY | NOT|  NOT|Encr|
  -----------------------------------------|----+-----+----+-----|----|
  Accounting-      363  8.1     Unsigned64 | M  |  P  |    |  V  | Y  |
    Input-Octets                           |    |     |    |     |    |
  Accounting-      364  8.2     Unsigned64 | M  |  P  |    |  V  | Y  |
    Output-Octets                          |    |     |    |     |    |
  Accounting-      365  8.3     Unsigned64 | M  |  P  |    |  V  | Y  |
    Input-Packets                          |    |     |    |     |    |
  Accounting-      366  8.4     Unsigned64 | M  |  P  |    |  V  | Y  |
    Output-Packets                         |    |     |    |     |    |
  Acct-Session-Time 46  8.5     Unsigned32 | M  |  P  |    |  V  | Y  |
  Acct-Authentic    45  8.6     Enumerated | M  |  P  |    |  V  | Y  |
  Acounting-Auth-  406  8.7     Enumerated | M  |  P  |    |  V  | Y  |
    Method                                 |    |     |    |     |    |
  Acct-Delay-Time   41  8.8     Unsigned32 | M  |  P  |    |  V  | Y  |
  Acct-Link-Count   51  8.9     Unsigned32 | M  |  P  |    |  V  | Y  |
  Acct-Tunnel-      68  8.10    OctetString| M  |  P  |    |  V  | Y  |
    Connection                             |    |     |    |     |    |
  Acct-Tunnel-      86  8.11    Unsigned32 | M  |  P  |    |  V  | Y  |
    Packets-Lost                           |    |     |    |     |    |
  -----------------------------------------|----+-----+----+-----|----|

8.1.  Accounting-Input-Octets AVP

  The Accounting-Input-Octets AVP (AVP Code 363) is of type Unsigned64
  and contains the number of octets received from the user.





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  For NAS usage, this AVP indicates how many octets have been received
  from the port in the course of this session.  It can only be present
  in ACR messages with an Accounting-Record-Type of INTERIM_RECORD or
  STOP_RECORD.

8.2.  Accounting-Output-Octets AVP

  The Accounting-Output-Octets AVP (AVP Code 364) is of type Unsigned64
  and contains the number of octets sent to the user.

  For NAS usage, this AVP indicates how many octets have been sent to
  the port in the course of this session.  It can only be present in
  ACR messages with an Accounting-Record-Type of INTERIM_RECORD or
  STOP_RECORD.

8.3.  Accounting-Input-Packets AVP

  The Accounting-Input-Packets (AVP Code 365) is of type Unsigned64 and
  contains the number of packets received from the user.

  For NAS usage, this AVP indicates how many packets have been received
  from the port over the course of a session being provided to a Framed
  User.  It can only be present in ACR messages with an Accounting-
  Record-Type of INTERIM_RECORD or STOP_RECORD.

8.4.  Accounting-Output-Packets AVP

  The Accounting-Output-Packets (AVP Code 366) is of type Unsigned64
  and contains the number of IP packets sent to the user.

  For NAS usage, this AVP indicates how many packets have been sent to
  the port over the course of a session being provided to a Framed
  User.  It can only be present in ACR messages with an Accounting-
  Record-Type of INTERIM_RECORD or STOP_RECORD.

8.5.  Acct-Session-Time AVP

  The Acct-Session-Time AVP (AVP Code 46) is of type Unsigned32 and
  indicates the length of the current session in seconds.  It can only
  be present in ACR messages with an Accounting-Record-Type of
  INTERIM_RECORD or STOP_RECORD.

8.6.  Acct-Authentic AVP

  The Acct-Authentic AVP (AVP Code 45) is of type Enumerated and
  specifies how the user was authenticated.  The supported values are
  listed in [RADIUSTypes].  The following list is informational:




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     1  RADIUS
     2  Local
     3  Remote
     4  Diameter

8.7.  Accounting-Auth-Method AVP

  The Accounting-Auth-Method AVP (AVP Code 406) is of type Enumerated.
  A NAS MAY include this AVP in an Accounting-Request message to
  indicate the method used to authenticate the user.  (Note that this
  is equivalent to the RADIUS MS-Acct-Auth-Type VSA attribute).

  The following values are defined:

     1  PAP
     2  CHAP
     3  MS-CHAP-1
     4  MS-CHAP-2
     5  EAP
     7  None

8.8.  Acct-Delay-Time

  The Acct-Delay-Time AVP (AVP Code 41) is of type Unsigned32 and
  indicates the number of seconds the Diameter client has been trying
  to send the Accounting-Request (ACR).  The accounting server may
  subtract this value from the time when the ACR arrives at the server
  to calculate the approximate time of the event that caused the ACR to
  be generated.

  This AVP is not used for retransmissions at the transport level (TCP
  or SCTP).  Rather, it may be used when an ACR command cannot be
  transmitted because there is no appropriate peer to transmit it to or
  was rejected because it could not be delivered.  In these cases, the
  command MAY be buffered and transmitted later, when an appropriate
  peer-connection is available or after sufficient time has passed that
  the destination-host may be reachable and operational.  If the ACR is
  resent in this way, the Acct-Delay-Time AVP SHOULD be included.  The
  value of this AVP indicates the number of seconds that elapsed
  between the time of the first attempt at transmission and the current
  attempt.










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8.9.  Acct-Link-Count

  The Acct-Link-Count AVP (AVP Code 51) is of type Unsigned32 and
  indicates the total number of links that have been active (current or
  closed) in a given multilink session at the time the accounting
  record is generated.  This AVP MAY be included in Accounting-Requests
  for any session that may be part of a multilink service.

  The Acct-Link-Count AVP may be used to make it easier for an
  accounting server to know when it has all the records for a given
  multilink service.  When the number of Accounting-Requests received
  with Accounting-Record-Type = STOP_RECORD and with the same Acct-
  Multi-Session-Id and unique Session-Ids equals the largest value of
  Acct-Link-Count seen in those Accounting-Requests, all STOP_RECORD
  Accounting-Requests for that multilink service have been received.

  The following example, showing eight Accounting-Requests, illustrates
  how the Acct-Link-Count AVP is used.  In the table below, only the
  relevant AVPs are shown, although additional AVPs containing
  accounting information will be present in the Accounting-Requests.

     Acct-Multi-                   Accounting-     Acct-
     Session-Id     Session-Id     Record-Type     Link-Count
     --------------------------------------------------------
       "...10"        "...10"      START_RECORD        1
       "...10"        "...11"      START_RECORD        2
       "...10"        "...11"      STOP_RECORD         2
       "...10"        "...12"      START_RECORD        3
       "...10"        "...13"      START_RECORD        4
       "...10"        "...12"      STOP_RECORD         4
       "...10"        "...13"      STOP_RECORD         4
       "...10"        "...10"      STOP_RECORD         4

8.10.  Acct-Tunnel-Connection AVP

  The Acct-Tunnel-Connection AVP (AVP Code 68) is of type OctetString
  and contains the identifier assigned to the tunnel session.  This
  AVP, along with the Tunnel-Client-Endpoint and Tunnel-Server-Endpoint
  AVPs, may be used to provide a means to uniquely identify a tunnel
  session for auditing purposes.

  The format of the identifier in this AVP depends upon the value of
  the Tunnel-Type AVP.  For example, to identify an L2TP tunnel
  connection fully, the L2TP Tunnel Id and Call Id might be encoded in
  this field.  The exact encoding of this field is implementation
  dependent.





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8.11.  Acct-Tunnel-Packets-Lost AVP

  The Acct-Tunnel-Packets-Lost AVP (AVP Code 86) is of type Unsigned32
  and contains the number of packets lost on a given link.

9.  RADIUS/Diameter Protocol Interactions

  This section describes some basic guidelines that servers acting as
  AAA Translation Agents may use.  A complete description of all the
  differences between RADIUS and Diameter is beyond the scope of this
  section and document.  Note that this document does not restrict
  implementations from creating additional translation methods, as long
  as the translation function doesn't violate the RADIUS or the
  Diameter protocols.

  Although the Diameter protocol is in many ways a superset of RADIUS
  functions, a number of RADIUS representations are not allowed, so
  that new capabilities can be used without the old problems.

  There are primarily two different situations that must be handled:
  one in which a RADIUS request is received that must be forwarded as a
  Diameter request, and another in which the inverse is true.  RADIUS
  does not support a peer-to-peer architecture, and server-initiated
  operations are generally not supported.  See [RADDynAuth] for an
  alternative.

  Some RADIUS attributes are encrypted.  RADIUS security and encryption
  techniques are applied on a hop-per-hop basis.  A Diameter agent will
  have to decrypt RADIUS attribute data entering the Diameter system,
  and if that information is forwarded, the agent MUST secure it by
  using Diameter specific techniques.

  Note that this section uses the two terms, "AVP" and "attribute", in
  a concise and specific manner.  The former is used to signify a
  Diameter AVP, and the latter to signify a RADIUS attribute.

9.1.  RADIUS Request Forwarded as Diameter Request

  This section describes the actions that should be taken when a
  Translation Agent receives a RADIUS message to be translated to a
  Diameter message.

  Note that RADIUS servers are assumed to be stateless.  It is also
  quite possible for the RADIUS messages that comprise the session
  (i.e., authentication and accounting messages) to be handled by
  different Translation Agents in the proxy network.  Therefore, a
  RADIUS/Diameter Translation Agent SHOULD NOT be assumed to have an
  accurate track on session-state information.



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  When a Translation Agent receives a RADIUS message, the following
  steps should be taken:

     -  If a Message-Authenticator attribute is present, the value MUST
        be checked but not included in the Diameter message.  If it is
        incorrect, the RADIUS message should be silently discarded.
        The gateway system SHOULD generate and include a Message-
        Authenticator in returned RADIUS responses.

     -  The transport address of the sender MUST be checked against the
        NAS identifying attributes.  See the description of NAS-
        Identifier and NAS-IP-Address below.

     -  The Translation Agent must maintain transaction state
        information relevant to the RADIUS request, such as the
        Identifier field in the RADIUS header, any existing RADIUS
        Proxy-State attribute, and the source IP address and port
        number of the UDP packet.  These may be maintained locally in a
        state table or saved in a Proxy-Info AVP group.  A Diameter
        Session-Id AVP value must be created using a session state
        mapping mechanism.

     -  If the RADIUS request contained a State attribute and the
        prefix of the data is "Diameter/", the data following the
        prefix contains the Diameter Origin-Host/Origin-Realm/Session-
        Id.  If no such attributes are present and the RADIUS command
        is an Access-Request, a new Session-Id is created.  The
        Session-Id is included in the Session-Id AVP.

     -  The Diameter Origin-Host and Origin-Realm AVPs MUST be created
        and added by using the information from an FQDN corresponding
        to the NAS-IP-Address attribute (preferred if available),
        and/or to the NAS-Identifier attribute.  (Note that the RADIUS
        NAS-Identifier is not required to be an FQDN.)

     -  The response MUST have an Origin-AAA-Protocol AVP added,
        indicating the protocol of origin of the message.

     -  The Proxy-Info group SHOULD be added, with the local server's
        identity specified in the Proxy-Host AVP.  This should ensure
        that the response is returned to this system.

     -  The Destination-Realm AVP is created from the information found
        in the RADIUS User-Name attribute.







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     -  If the RADIUS User-Password attribute is present, the password
        must be unencrypted by using the link's RADIUS shared secret.
        The unencrypted value must be forwarded in a User-Password AVP
        using Diameter security.

     -  If the RADIUS CHAP-Password attribute is present, the Ident and
        Data portion of the attribute are used to create the CHAP-Auth
        grouped AVP.

     -  If the RADIUS message contains an address attribute, it MUST be
        converted to the appropriate Diameter AVP and type.

     -  If the RADIUS message contains Tunnel information [RADTunnels],
        the attributes or tagged groups should each be converted to a
        Diameter Tunneling Grouped AVP set.  If the tunnel information
        contains a Tunnel-Password attribute, the RADIUS encryption
        must be resolved, and the password forwarded, by using Diameter
        security methods.

     -  If the RADIUS message received is an Accounting-Request, the
        Acct-Status-Type attribute value must be converted to a
        Accounting-Record-Type AVP value.  If the Acct-Status-Type
        attribute value is STOP, the local server MUST issue a
        Session-Termination-Request message once the Diameter
        Accounting-Answer message has been received.

     -  If the Accounting message contains an Acct-Termination-Cause
        attribute, it should be translated to the equivalent
        Termination-Cause AVP value.  (see below)

     -  If the RADIUS message contains the Accounting-Input-Octets,
        Accounting-Input-Packets, Accounting-Output-Octets, or
        Accounting-Output-Packets, these attributes must be converted
        to the Diameter equivalents.  Further, if the Acct-Input-
        Gigawords or Acct-Output-Gigawords attributes are present,
        these must be used to properly compute the Diameter accounting
        AVPs.

  The corresponding Diameter response is always guaranteed to be
  received by the same Translation Agent that translated the original
  request, due to the contents of the Proxy-Info AVP group in the
  Diameter request.  The following steps are applied to the response
  message during the Diameter-to-RADIUS translation:

     -  If the Diameter Command-Code is set to AA-Answer and the
        Result-Code AVP is set to DIAMETER_MULTI_ROUND_AUTH, the
        gateway must send a RADIUS Access-Challenge.  This must have
        the Origin-Host, Origin-Realm, and Diameter Session-Id AVPs



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        encapsulated in the RADIUS State attribute, with the prefix
        "Diameter/", concatenated in the above order separated with "/"
        characters, in UTF-8 [UTF-8].  This is necessary to ensure that
        the Translation Agent receiving the subsequent RADIUS Access-
        Request will have access to the Session Identifier and be able
        to set the Destination-Host to the correct value.  If the
        Multi-Round-Time-Out AVP is present, the value of the AVP MUST
        be inserted in the RADIUS Session-Timeout AVP.

     -  If the Command-Code is set to AA-Answer, the Diameter Session-
        Id AVP is saved in a new RADIUS Class attribute whose format
        consists of the string "Diameter/" followed by the Diameter
        Session Identifier.  This will ensure that the subsequent
        Accounting messages, which could be received by any Translation
        Agent, would have access to the original Diameter Session
        Identifier.
     -  If a Proxy-State attribute was present in the RADIUS request,
        the same attribute is added in the response.  This information
        may be found in the Proxy-Info AVP group, or in a local state
        table.

     -  If state information regarding the RADIUS request was saved in
        a Proxy-Info AVP or local state table, the RADIUS Identifier
        and UDP IP Address and port number are extracted and used in
        issuing the RADIUS reply.

  When translating a Diameter AA-Answer (with successful result code)
  to RADIUS Access-Accept that contains a Session-Timeout or
  Authorization-Lifetime AVP, take the following steps:

     -  If the Diameter message contains a Session-Timeout AVP but no
        Authorization-Lifetime AVP, translate it to a Session-Timeout
        attribute (not a Termination-Action).

     -  If the Diameter message contains an Authorization-Lifetime AVP
        but no Session-Timeout AVP, translate it to a Session-Timeout
        attribute and a Termination-Action set to AA-REQUEST.  (Remove
        Authorization-Lifetime and Re-Auth-Request-Type.)

     -  If the Diameter message has both, the Session-Timeout must be
        greater than or equal to the Authorization-Lifetime (required
        by [BASE]).  Translate it to a Session-Timeout value (with
        value from Authorization-Lifetime AVP, the smaller one) and
        with the Termination-Action set to AA-REQUEST.  (Remove the
        Authorization-Lifetime and Re-Auth-Request-Type.)






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RFC 4005       Diameter Network Access Server Application    August 2005


9.1.1.  RADIUS Dynamic Authorization Considerations

  A Diameter/RADIUS gateway may communicate with a server that
  implements RADIUS Dynamic Authorization [RADDynAuth].  If the server
  supports these functions, it MUST be listening on the assigned port
  and would receive RADIUS CoA-Request and Disconnect-Request messages.
  These can be mapped into the Diameter Re-Auth-Request (RAR) and
  Abort-Session-Request (ASR) message exchanges, respectively [BASE].

  If the [RADDynAuth] is not supported, the port would not be active
  and the RADIUS server would receive an ICMP Port Unreachable
  indication.  Alternatively, if the messages are received but with an
  inappropriate Service-Type, the gateway can respond with the
  appropriate NAK message and an Error-Cause attribute with the value
  of 405, "Unsupported Service".

  The RADIUS CoA-Request and Disconnect-Request messages will not
  contain a Diameter Session-Id.  Diameter requires that this value
  match an active session context.  The gateway MUST have a session Id
  cache (or other means) to identify the sessions these functions
  pertain to.  If unable to identify the session, the gateway (or NAS)
  should return an Error-Cause value 503, "Session Context Not Found".

  The RADIUS CoA-Request message only supports a change of
  authorization attributes, and the received CoA-Request SHOULD include
  a Service-Type of "Authorize-Only".  This indicates an extended
  exchange request by the rules given in [RADDynAuth] section 3.2, note
  6.  This is the only type of exchange supported by Diameter [BASE].

  For the CoA-Request, the translated RAR message will have a Re-Auth-
  Type of AUTHORIZE_ONLY.  The returned RAA will be translated into a
  CoA-NAK with Error-Cause "Request Initiated".  The gateway's Diameter
  client SHOULD also start a reauthorization sequence by sending an AAR
  message, which will be translated into an Access-Request message.
  The RADIUS server will use the Access-Accept (or Access-Reject)
  message to convey the new authorization attributes, which the gateway
  will pass back in an AAA message.

  Any attributes included in the COA-Request or Access-Accept message
  are to be considered mandatory in Diameter.  If they cannot be
  supported, they MUST result in an error message return to the RADIUS
  server, with an Error-Cause of "Unsupported Attribute".  The Diameter
  NAS will attempt to apply all the attributes supplied in the AA
  message to the session.

  A RADIUS Disconnect-Request message received by the gateway would be
  translated to a Diameter Abort-Session-Request (ASR) message [BASE].
  The results will be returned by the Diameter client in an Abort-



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  Session-Answer (ASA) message.  A success indication would translate
  to a RADIUS Disconnect-ACK, and a failure would generate a
  Disconnect-NAK.

9.2.  Diameter Request Forwarded as RADIUS Request

  When a server receives a Diameter request to be forwarded to a RADIUS
  entity, the following are examples of the steps that may be taken:

     -  The Origin-Host AVP's value is inserted into the NAS-Identifier
        attribute.

     -  The following information MUST be present in the corresponding
        Diameter response and therefore MUST be saved, either in a
        local state table or encoded in a RADIUS Proxy-State attribute:

           1. Origin-Host AVP
           2. Session-Id AVP
           3. Proxy-Info AVP
           4. Any other AVP that MUST be present in the response and
              has no corresponding RADIUS attribute.

     -  If the CHAP-Auth AVP is present, the grouped AVPs are used to
        create the RADIUS CHAP-Password attribute data.

     -  If the User-Password AVP is present, the data should be
        encrypted and forwarded by using RADIUS rules.  The same is
        true for any other RADIUS-encrypted attribute values.

     -  AVPs of the type Address must be translated to the
        corresponding RADIUS attribute.

     -  If the Accounting-Input-Octets, Accounting-Input-Packets,
        Accounting-Output-Octets, or Accounting-Output-Packets AVPs are
        present, they must be translated to the corresponding RADIUS
        attributes.  If the value of the Diameter AVPs do not fit
        within a 32-bit RADIUS attribute, the RADIUS Acct-Input-
        Gigawords and Acct-Output-Gigawords must be used.

     -  If the RADIUS link supports the Message-Authenticator attribute
        [RADIUSExt], it SHOULD be generated and added to the request.

  When the corresponding response is received by the Translation Agent,
  which is guaranteed in the RADIUS protocol, the following steps may
  be taken:






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     -  If the RADIUS code is set to Access-Challenge, a Diameter AA-
        Answer message is created with the Result-Code set to
        DIAMETER_MULTI_ROUND_AUTH.  If the Session-Timeout AVP is
        present in the RADIUS message, its value is inserted into the
        Multi-Round-Time-Out AVP.

     - If a Proxy-State attribute is present, extract the encoded
        information; otherwise, retrieve the original Proxy-Info AVP
        group information from the local state table.

     -  The response's Origin-Host information is created from the FQDN
        of the RADIUS message's source IP address.  The same FQDN is
        also stored to a Route-Record AVP.

     -  The response's Destination-Host AVP is copied from the saved
        request's Origin-Host information.

     -  The Session-Id information can be recovered from local state,
        or from the constructed State or Proxy-State attribute, as
        above.

     -  If a Proxy-Info AVP was present in the request, the same AVP
        MUST be added to the response.

     -  If the RADIUS State attributes are present, they must be
        present in the Diameter response, minus those added by the
        gateway.

     -  Any other AVPs that were saved at request time, and that MUST
        be present in the response, are added to the message.

  When translating a RADIUS Access-Accept to Diameter AA-Answer that
  contains a Session-Timeout attribute, do the following:

     -  If the RADIUS message contains a Session-Timeout attribute and
        a Termination-Action attribute set to DEFAULT (or no
        Termination-Action attribute at all), translate it to AA-Answer
        with a Session-Timeout AVP and remove the Termination-Action
        attribute.

     -  If the RADIUS message contains a Session-Timeout attribute and
        a Termination-Action attribute set to AA-REQUEST, translate it
        to AA-Answer with Authorization-Lifetime AVP and with Re-Auth-
        Request-Type set to AUTHORIZE_AUTHENTICATE and remove the
        Session-Timeout attribute.






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RFC 4005       Diameter Network Access Server Application    August 2005


9.2.1.  RADIUS Dynamic Authorization Considerations

  A RADIUS/Diameter gateway communicating with a RADIUS client that
  implements RADIUS Dynamic Authorization [RADDynAuth] may translate
  Diameter Re-Auth-Request (RAR) messages and Abort-Session-Request
  (ASR) messages [BASE] into RADIUS CoA-Request and Disconnect-Request
  messages respectively.

  If the RADIUS client does not support the capability, the gateway
  will receive an ICMP Port Unreachable indication when it transmits
  the RADIUS message.  Even if the NAS supports [RADDynAuth], it may
  not support the Service-Type in the request message.  In this case it
  will respond with a NAK message and (optionally) an Error-Cause
  attribute with value 405, "Unsupported Service".  If the gateway
  encounters these error conditions, or if it does not support
  [RADDynAuth], it sends a Diameter Answer message with an Result-Code
  AVP of "DIAMETER_COMMAND_UNSUPPORTED" to the AAA server.

  When encoding the RADIUS messages, the gateway MUST include the
  Diameter Session-ID in the RADIUS State attribute value, as mentioned
  above.  The RADIUS client should return it in the response.

  A Diameter Re-Auth-Request (RAR) message [BASE] received by the
  gateway will be translated into a RADIUS CoA-Request and sent to the
  RADIUS client.  The RADIUS client should respond with a CoA-ACK or
  CoA-NAK message, which the gateway should translate into a Re-Auth-
  Answer (RAA) message.

  If the gateway receives a RADIUS CoA-NAK response containing a
  Service-Type Attribute with value "Authorize Only" and an Error-Cause
  Attribute with value "Request Initiated", this indicates an extended
  exchange request per [RADDynAuth] section 3.2, note 6.

  The response is translated to a Diameter Re-Auth-Answer (RAA) with a
  Result-Code AVP of "DIAMETER_LIMITED_SUCCESS" sent to the AAA server.

  Subsequently, the gateway should receive a RADIUS Access-Request from
  the NAS, with a Service-Type of "Authorize Only".  This is translated
  into a Diameter AA-Request with an Auth-Request-Type AVP of
  AUTHORIZE_ONLY and sent to the AAA server.  The AAA server will then
  reply with a Diameter AA-Answer, which is translated into a RADIUS
  Access-Accept or Access-Reject, depending on the value of the
  Result-Code AVP.

  A Diameter Abort-Session-Request (ASR) message [BASE] received by the
  gateway will be translated into a RADIUS Disconnect-Request and sent
  to the RADIUS client.  The RADIUS client should respond with a




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RFC 4005       Diameter Network Access Server Application    August 2005


  Disconnect-ACK or Disconnect-NAK message, which the gateway should
  translate into an Abort-Session-Answer (ASA) message.

  If the gateway receives a RADIUS Disconnect-NAK response containing a
  Service-Type Attribute with value "Authorize Only" and an Error-Cause
  Attribute with value "Request Initiated", the Disconnect-NAK response
  is translated into a Diameter Abort-Session-Answer (ASA) with a
  Result-Code AVP of "DIAMETER_LIMITED_SUCCESS" sent to the AAA server.

  Subsequently, the gateway should receive a RADIUS Access-Request from
  the NAS, with a Service-Type of "Authorize Only".  This is translated
  into a Diameter AA-Request with an Auth-Request-Type AVP of
  AUTHORIZE_ONLY and sent to the AAA server.  The AAA server will then
  reply with a Diameter AA-Answer, which is translated into a RADIUS
  Access-Accept or Access-Reject, depending on the value of the
  Result-Code AVP.

9.3.  AVPs Used Only for Compatibility

  The AVPs defined in this section SHOULD only be used for backwards
  compatibility when a Diameter/RADIUS translation function is invoked
  and are not typically originated by Diameter systems during normal
  operations.

                                           +---------------------+
                                           |    AVP Flag rules   |
                                           |----+-----+----+-----|----+
                  AVP  Section             |    |     |SHLD| MUST|    |
  Attribute Name  Code Defined  Value Type |MUST| MAY | NOT|  NOT|Encr|
  -----------------------------------------|----+-----+----+-----|----|
  NAS-Identifier    32  9.3.1   UTF8String | M  |  P  |    |  V  | Y  |
  NAS-IP-Address     4  9.3.2   OctetString| M  |  P  |    |  V  | Y  |
  NAS-IPv6-Address  95  9.3.3   OctetString| M  |  P  |    |  V  | Y  |
  State             24  9.3.4   OctetString| M  |  P  |    |  V  | Y  |
  Termination-     295  9.3.5   Enumerated | M  |  P  |    |  V  | Y  |
     Cause                                 |    |     |    |     |    |
  Origin-AAA-      408  9.3.6   Enumerated | M  |  P  |    |  V  | Y  |
     Protocol                              |    |     |    |     |    |
  -----------------------------------------|----+-----+----+-----|----|

9.3.1.  NAS-Identifier AVP

  The NAS-Identifier AVP (AVP Code 32) [RADIUS] is of type UTF8String
  and contains the identity of the NAS providing service to the user.
  This AVP SHOULD only be added by a RADIUS/Diameter Translation Agent.
  When this AVP is present, the Origin-Host AVP identifies the NAS
  providing service to the user.




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  In RADIUS it would be possible for a rogue NAS to forge the NAS-
  Identifier attribute.  Diameter/RADIUS translation agents SHOULD
  attempt to check a received NAS-Identifier attribute against the
  source address of the RADIUS packet, by doing an A/AAAA RR query.  If
  the NAS-Identifier attribute contains an FQDN, then such a query
  would resolve to an IP address matching the source address.  However,
  the NAS-Identifier attribute is not required to contain an FQDN, so
  such a query could fail.  If it fails, an error should be logged, but
  no action should be taken, other than a reverse lookup on the source
  address and insert the resulting FQDN into the Route-Record AVP.

  Diameter agents and servers SHOULD check whether a NAS-Identifier AVP
  corresponds to an entry in the Route-Record AVP.  If no match is
  found, then an error is logged, but no other action is taken.

9.3.2.  NAS-IP-Address AVP

  The NAS-IP-Address AVP (AVP Code 4) [RADIUS] is of type OctetString
  and contains the IP Address of the NAS providing service to the user.
  This AVP SHOULD only be added by a RADIUS/Diameter Translation Agent.
  When this AVP is present, the Origin-Host AVP identifies the NAS
  providing service to the user.

  In RADIUS it would be possible for a rogue NAS to forge the NAS-IP-
  Address attribute value.  Diameter/RADIUS translation agents MUST
  check a received NAS-IP-Address or NAS-IPv6-Address attribute against
  the source address of the RADIUS packet.  If they do not match and
  the Diameter/RADIUS translation agent does not know whether the
  packet was sent by a RADIUS proxy or NAS (e.g., no Proxy-State
  attribute), then by default it is assumed that the source address
  corresponds to a RADIUS proxy, and that the NAS Address is behind
  that proxy, potentially with some additional RADIUS proxies in
  between.  The Diameter/RADIUS translation agent MUST insert entries
  in the Route-Record AVP corresponding to the apparent route.  This
  implies doing a reverse lookup on the source address and NAS-IP-
  Address or NAS-IPv6-Address attributes to determine the corresponding
  FQDNs.

  If the source address and the NAS-IP-Address or NAS-IPv6-Address do
  not match, and the Diameter/RADIUS translation agent knows that it is
  talking directly to the NAS (e.g., there are no RADIUS proxies
  between it and the NAS), then the error should be logged, and the
  packet MUST be discarded.

  Diameter agents and servers MUST check whether the NAS-IP-Address AVP
  corresponds to an entry in the Route-Record AVP.  This is done by
  doing a reverse lookup (PTR RR) for the NAS-IP-Address to retrieve
  the corresponding FQDN, and by checking for a match with the Route-



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  Record AVP.  If no match is found, then an error is logged, but no
  other action is taken.

9.3.3.  NAS-IPv6-Address AVP

  The NAS-IPv6-Address AVP (AVP Code 95) [RADIUSIPv6] is of type
  OctetString and contains the IPv6 Address of the NAS providing
  service to the user.  This AVP SHOULD only be added by a
  RADIUS/Diameter Translation Agent.  When this AVP is present, the
  Origin-Host AVP identifies the NAS providing service to the user.

  In RADIUS it would be possible for a rogue NAS to forge the NAS-
  IPv6-Address attribute.  Diameter/RADIUS translation agents MUST
  check a received NAS-IPv6-Address attribute against the source
  address of the RADIUS packet.  If they do not match and the
  Diameter/RADIUS translation agent does not know whether the packet
  was sent by a RADIUS proxy or NAS (e.g., no Proxy-State attribute),
  then by default it is assumed that the source address corresponds to
  a RADIUS proxy, and that the NAS-IPv6-Address is behind that proxy,
  potentially with some additional RADIUS proxies in between.  The
  Diameter/RADIUS translation agent MUST insert entries in the Route-
  Record AVP corresponding to the apparent route.  This implies doing a
  reverse lookup on the source address and NAS-IPv6-Address attributes
  to determine the corresponding FQDNs.

  If the source address and the NAS-IPv6-Address do not match, and the
  Diameter/RADIUS translation agent knows that it is talking directly
  to the NAS (e.g., there are no RADIUS proxies between it and the
  NAS), then the error should be logged, and the packet MUST be
  discarded.

  Diameter agents and servers MUST check whether the NAS-IPv6-Address
  AVP corresponds to an entry in the Route-Record AVP.  This is done by
  doing a reverse lookup (PTR RR) for the NAS-IPv6-Address to retrieve
  the corresponding FQDN, and by checking for a match with the Record-
  Route AVP.  If no match is found, then an error is logged, but no
  other action is taken.

9.3.4.  State AVP

  The State AVP (AVP Code 24) [RADIUS] is of type OctetString and has
  two uses in the Diameter NAS application.

  The State AVP MAY be sent by a Diameter Server to a NAS in an AA-
  Response command that contains a Result-Code of
  DIAMETER_MULTI_ROUND_AUTH.  If so, the NAS MUST return it unmodified
  in the subsequent AA-Request command.




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  The State AVP MAY also be sent by a Diameter Server to a NAS in an
  AA-Response command that also includes a Termination-Action AVP with
  the value of AA-REQUEST.  If the NAS performs the Termination-Action
  by sending a new AA-Request command upon termination of the current
  service, it MUST return the State AVP unmodified in the new request
  command.

  In either usage, the NAS MUST NOT interpret the AVP locally.  Usage
  of the State AVP is implementation dependent.

9.3.5.  Termination-Cause AVP Code Values

  This section defines a mapping between Termination-Cause AVP code
  values and RADIUS Acct-Terminate-Cause attribute code values from RFC
  2866 [RADIUSAcct] and [RADIUSTypes], thereby allowing a
  RADIUS/Diameter Translation Agent to convert between the attribute
  and AVP values.  This section thus extends the definitions in the
  "Termination-Cause AVP" section of the Base Diameter specification.

































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RFC 4005       Diameter Network Access Server Application    August 2005


  The table in this section defines the mapping between Termination-
  Cause AVP and RADIUS Acct-Terminate-Cause causes.

                                +-----------------------+
                                |         Value         |
                                +-----------+-----------+
  Cause Value Name              |  RADIUS   | Diameter  |
  ------------------------------|-----------+-----------+
  User Request                  |     1     |   11      |
  Lost Carrier                  |     2     |   12      |
  Lost Service                  |     3     |   13      |
  Idle Timeout                  |     4     |   14      |
  Session Timeout               |     5     |   15      |
  Admin Reset                   |     6     |   16      |
  Admin Reboot                  |     7     |   17      |
  Port Error                    |     8     |   18      |
  NAS Error                     |     9     |   19      |
  NAS Request                   |     10    |   20      |
  NAS Reboot                    |     11    |   21      |
  Port Unneeded                 |     12    |   22      |
  Port Preempted                |     13    |   23      |
  Port Suspended                |     14    |   24      |
  Service Unavailable           |     15    |   25      |
  Callback                      |     16    |   26      |
  User Error                    |     17    |   27      |
  Host Request                  |     18    |   28      |
  Supplicant Restart            |     19    |   29      |  [RAD802.1X]
  Reauthentication Failure      |     20    |   30      |  [RAD802.1X]
  Port Reinit                   |     21    |   31      |  [RAD802.1X]
  Port Disabled                 |     22    |   32      |  [RAD802.1X]
  ------------------------------|-----------+-----------+

  From RFC 2866, the termination causes are as follows:

  User Request         User requested termination of service, for
                       example with LCP Terminate or by logging out.

  Lost Carrier         DCD was dropped on the port.

  Lost Service         Service can no longer be provided; for
                       example, user's connection to a host was
                       interrupted.

  Idle Timeout         Idle timer expired.

  Session Timeout      Maximum session length timer expired.

  Admin Reset          Administrator reset the port or session.



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  Admin Reboot         Administrator is ending service on the NAS,
                       for example, prior to rebooting the NAS.

  Port Error           NAS detected an error on the port that
                       required ending the session.

  NAS Error            NAS detected an error (other than on the
                       port) that required ending the session.

  NAS Request          NAS ended the session for a non-error reason not
                       otherwise listed here.

  NAS Reboot           NAS ended the session to reboot
                       non-administratively ("crash").

  Port Unneeded        NAS ended the session because resource usage
                       fell below a low-water mark (for example, if
                       a bandwidth-on-demand algorithm decided that
                       the port was no longer needed).

  Port Preempted       NAS ended the session to allocate the
                       port to a higher priority use.

  Port Suspended       NAS ended the session to suspend a virtual
                       session.

  Service Unavailable  NAS was unable to provide requested service.

  Callback             NAS is terminating the current session
                       to perform callback for a new session.

  User Error           Input from user is in error, causing
                       session termination.

  Host Request         Login Host terminated session normally.

9.3.6.  Origin-AAA-Protocol

  The Origin-AAA-Protocol AVP (AVP Code 408) is of the type Enumerated
  and should be inserted in a Diameter message translated by a gateway
  system from another AAA protocol, such as RADIUS.  It identifies the
  source protocol of the message to the Diameter system receiving the
  message.

  The supported values are:

        1       RADIUS




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RFC 4005       Diameter Network Access Server Application    August 2005


9.4.  Prohibited RADIUS Attributes

  The following RADIUS attributes MUST NOT appear in a Diameter
  message.  Instead, they are translated to other Diameter AVPs or
  handled in some special manner.  The rules for the treatment of the
  attributes are discussed in sections 9.1, 9.2, and 9.6.

  Attribute Description       Defined     Nearest Diameter AVP
  -----------------------------------------------------------------
   3 CHAP-Password            RFC 2865    CHAP-Auth Group
  26 Vendor-Specific          RFC 2865    Vendor Specific AVP
  29 Termination-Action       RFC 2865    Authorization-Lifetime
  40 Acct-Status-Type         RFC 2866    Accounting-Record-Type
  42 Acct-Input-Octets        RFC 2866    Accounting-Input-Octets
  43 Acct-Output-Octets       RFC 2866    Accounting-Output-Octets
  47 Acct-Input-Packets       RFC 2866    Accounting-Input-Packets
  48 Acct-Output-Packets      RFC 2866    Accounting-Output-Packets
  49 Acct-Terminate-Cause     RFC 2866    Termination-Cause
  52 Acct-Input-Gigawords     RFC 2869    Accounting-Input-Octets
  53 Acct-Output-Gigawords    RFC 2869    Accounting-Output-Octets
  80 Message-Authenticator    RFC 2869    none - check and discard

9.5.  Translatable Diameter AVPs

  In general, Diameter AVPs that are not RADIUS compatible have code
  values greater than 255.  The table in the section above shows the
  AVPs that can be converted into RADIUS attributes.

  Another problem may occur with Diameter AVP values that may be more
  than 253 octets in length.  Some RADIUS attributes (including but not
  limited to (8)Reply-Message, (79)EAP-Message, and (77)Connect-Info)
  allow concatenation of multiple instances to overcome this
  limitation.  If this is not possible, a Result-Code of
  DIAMETER_INVALID_AVP_LENGTH should be returned.

9.6.  RADIUS Vendor Specific Attributes

  RADIUS supports the inclusion of Vendor Specific Attributes (VSAs)
  through the use of attribute 26.  The recommended format [RADIUS] of
  the attribute data field includes a 4 octet vendor code followed by a
  one octet vendor type field and a one octet length field.  The last
  two fields MAY be repeated.

  A system communicating between Diameter and RADIUS MAY have specific
  knowledge of vendor formats, and MAY be able to translate between the
  two formats.  However, given the deployment of many RADIUS vendor
  formats that do not follow the example format in RFC 2865 [RADIUS],
  (e.g., those that use a longer vendor type code) the translations in



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RFC 4005       Diameter Network Access Server Application    August 2005


  the next two sections will not work in general for those VSAs.  RFC
  2865 states that a robust implementation SHOULD support the field as
  undistinguished octets.

  Systems that don't have vendor format knowledge MAY discard such
  attributes without knowing a suitable translation.  An alternative
  format is under consideration [VSA], which proposes encodings that
  would preserve the native information and not require vendor
  knowledge in the gateway system.

  The following sections are an example for translating RADIUS VSAs
  that use the example RADIUS format, and Diameter VSAs that have type
  codes less than 255, and value field lengths less than 252.

9.6.1.  Forwarding a Diameter Vendor Specific AVP as a RADIUS VSA

  For Type codes less than 255, the value field length MUST be less
  than 252 or the AVP will be discarded.  The RADIUS VSA attribute
  should consist of the following fields;

     RADIUS Type = 26, Vendor Specific Attribute
     RADIUS Length = total length of attribute (header + data)
     RADIUS Vendor code = Diameter Vendor code
     RADIUS Vendor type code = low order byte of Diameter AVP code
     RADIUS Vendor data length = length of Diameter data

  If the Diameter AVP code is greater than 255, then the RADIUS
  speaking code may use a Vendor specific field coding, if it knows one
  for that vendor.  Otherwise, the AVP will be ignored.  If it is
  flagged as Mandatory, a "DIAMETER_AVP_UNSUPPORTED" Result-Code will
  be returned, and the RADIUS message will not be sent.

9.6.2.  Forwarding a RADIUS VSA as a Diameter Vendor Specific AVP

  The Diameter AVP will consist of the following fields:

     Diameter Flags: V=1, M=0, P=0
     Diameter Vendor code = RADIUS VSA Vendor code
     Diameter AVP code = RADIUS VSA Vendor type code
     Diameter AVP length = length of AVP (header + data)
     Diameter Data = RADIUS VSA vendor data

  Note that the VSAs are considered optional by RADIUS rules, and this
  specification does not set the Mandatory flag.  If an implementor
  desires a VSA be made mandatory because it represents a required
  service policy, the RADIUS gateway should have a process to set the
  bit on the Diameter side.




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RFC 4005       Diameter Network Access Server Application    August 2005


  If the RADIUS receiving code knows of vendor specific field
  interpretations for the specific vendor, it may employ them to parse
  an extended AVP code or data length.  Otherwise the recommended
  standard fields will be used.

  Nested Multiple vendor data fields MUST be expanded into multiple
  Diameter AVPs.

10.  AVP Occurrence Tables

  The following tables present the AVPs used by NAS applications in NAS
  messages and specify in which Diameter messages they MAY or MAY NOT
  be present.  [BASE] messages and AVPs are not described in this
  document.  Note that AVPs that can only be present within a Grouped
  AVP are not represented in this table.

  The table uses the following symbols:

     0     The AVP MUST NOT be present in the message.
     0+    Zero or more instances of the AVP MAY be present in the
           message.
     0-1   Zero or one instance of the AVP MAY be present in the
           message.
     1     One instance of the AVP MUST be present in the message.

10.1.  AA-Request/Answer AVP Table

  The table in this section is limited to the Command Codes defined in
  this specification.

                                +-----------+
                                |  Command  |
                                |-----+-----+
  Attribute Name                | AAR | AAA |
  ------------------------------|-----+-----+
  Acct-Interim-Interval         | 0   | 0-1 |
  ARAP-Challenge-Response       | 0   | 0-1 |
  ARAP-Features                 | 0   | 0-1 |
  ARAP-Password                 | 0-1 | 0   |
  ARAP-Security                 | 0-1 | 0-1 |
  ARAP-Security-Data            | 0+  | 0+  |
  ARAP-Zone-Access              | 0   | 0-1 |
  Auth-Application-Id           | 1   | 1   |
  Auth-Grace-Period             | 0-1 | 0-1 |
  Auth-Request-Type             | 1   | 1   |
  Auth-Session-State            | 0-1 | 0-1 |
  Authorization-Lifetime        | 0-1 | 0-1 |
  ------------------------------|-----+-----+



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RFC 4005       Diameter Network Access Server Application    August 2005


                                +-----------+
                                |  Command  |
                                |-----+-----+
  Attribute Name                | AAR | AAA |
  ------------------------------|-----+-----+
  Callback-Id                   | 0   | 0-1 |
  Callback-Number               | 0-1 | 0-1 |
  Called-Station-Id             | 0-1 | 0   |
  Calling-Station-Id            | 0-1 | 0   |
  CHAP-Auth                     | 0-1 | 0   |
  CHAP-Challenge                | 0-1 | 0   |
  Class                         | 0   | 0+  |
  Configuration-Token           | 0   | 0+  |
  Connect-Info                  | 0+  | 0   |
  Destination-Host              | 0-1 | 0   |
  Destination-Realm             | 1   | 0   |
  Error-Message                 | 0   | 0-1 |
  Error-Reporting-Host          | 0   | 0-1 |
  Failed-AVP                    | 0+  | 0+  |
  Filter-Id                     | 0   | 0+  |
  Framed-Appletalk-Link         | 0   | 0-1 |
  Framed-Appletalk-Network      | 0   | 0+  |
  Framed-Appletalk-Zone         | 0   | 0-1 |
  Framed-Compression            | 0+  | 0+  |
  Framed-Interface-Id           | 0-1 | 0-1 |
  Framed-IP-Address             | 0-1 | 0-1 |
  Framed-IP-Netmask             | 0-1 | 0-1 |
  Framed-IPv6-Prefix            | 0+  | 0+  |
  Framed-IPv6-Pool              | 0   | 0-1 |
  Framed-IPv6-Route             | 0   | 0+  |
  Framed-IPX-Network            | 0   | 0-1 |
  Framed-MTU                    | 0-1 | 0-1 |
  Framed-Pool                   | 0   | 0-1 |
  Framed-Protocol               | 0-1 | 0-1 |
  Framed-Route                  | 0   | 0+  |
  Framed-Routing                | 0   | 0-1 |
  Idle-Timeout                  | 0   | 0-1 |
  Login-IP-Host                 | 0+  | 0+  |
  Login-IPv6-Host               | 0+  | 0+  |
  Login-LAT-Group               | 0-1 | 0-1 |
  Login-LAT-Node                | 0-1 | 0-1 |
  Login-LAT-Port                | 0-1 | 0-1 |
  Login-LAT-Service             | 0-1 | 0-1 |
  Login-Service                 | 0   | 0-1 |
  Login-TCP-Port                | 0   | 0-1 |
  Multi-Round-Time-Out          | 0   | 0-1 |
  ------------------------------|-----+-----+




Calhoun, et al.             Standards Track                    [Page 72]

RFC 4005       Diameter Network Access Server Application    August 2005


                                +-----------+
                                |  Command  |
                                |-----+-----+
  Attribute Name                | AAR | AAA |
  ------------------------------|-----+-----+
  NAS-Filter-Rule               | 0   | 0+  |
  NAS-Identifier                | 0-1 | 0   |
  NAS-IP-Address                | 0-1 | 0   |
  NAS-IPv6-Address              | 0-1 | 0   |
  NAS-Port                      | 0-1 | 0   |
  NAS-Port-Id                   | 0-1 | 0   |
  NAS-Port-Type                 | 0-1 | 0   |
  Origin-AAA-Protocol           | 0-1 | 0-1 |
  Origin-Host                   | 1   | 1   |
  Origin-Realm                  | 1   | 1   |
  Origin-State-Id               | 0-1 | 0-1 |
  Originating-Line-Info         | 0-1 | 0   |
  Password-Retry                | 0   | 0-1 |
  Port-Limit                    | 0-1 | 0-1 |
  Prompt                        | 0   | 0-1 |
  Proxy-Info                    | 0+  | 0+  |
  QoS-Filter-Rule               | 0   | 0+  |
  Re-Auth-Request-Type          | 0   | 0-1 |
  Redirect-Host                 | 0   | 0+  |
  Redirect-Host-Usage           | 0   | 0-1 |
  Redirect-Max-Cache-Time       | 0   | 0-1 |
  Reply-Message                 | 0   | 0+  |
  Result-Code                   | 0   | 1   |
  Route-Record                  | 0+  | 0+  |
  Service-Type                  | 0-1 | 0-1 |
  Session-Id                    | 1   | 1   |
  Session-Timeout               | 0   | 0-1 |
  State                         | 0-1 | 0-1 |
  Tunneling                     | 0+  | 0+  |
  User-Name                     | 0-1 | 0-1 |
  User-Password                 | 0-1 | 0   |
  ------------------------------|-----+-----+

10.2.  Accounting AVP Tables

  The tables in this section are used to show which AVPs defined in
  this document are to be present and used in NAS application
  Accounting messages.  These AVPs are defined in this document, as
  well as in [BASE] and [RADIUSAcct].







Calhoun, et al.             Standards Track                    [Page 73]

RFC 4005       Diameter Network Access Server Application    August 2005


10.2.1.  Accounting Framed Access AVP Table

  The table in this section is used when the Service-Type specifies
  Framed Access.

                                         +-----------+
                                         |  Command  |
                                         |-----+-----+
  Attribute Name                         | ACR | ACA |
  ---------------------------------------|-----+-----+
  Accounting-Auth-Method                 | 0-1 | 0   |
  Accounting-Input-Octets                | 1   | 0   |
  Accounting-Input-Packets               | 1   | 0   |
  Accounting-Output-Octets               | 1   | 0   |
  Accounting-Output-Packets              | 1   | 0   |
  Accounting-Record-Number               | 0-1 | 0-1 |
  Accounting-Record-Type                 | 1   | 1   |
  Accounting-Realtime-Required           | 0-1 | 0-1 |
  Accounting-Sub-Session-Id              | 0-1 | 0-1 |
  Acct-Application-Id                    | 0-1 | 0-1 |
  Acct-Session-Id                        | 1   | 0-1 |
  Acct-Multi-Session-Id                  | 0-1 | 0-1 |
  Acct-Authentic                         | 1   | 0   |
  Acct-Delay-Time                        | 0-1 | 0   |
  Acct-Interim-Interval                  | 0-1 | 0-1 |
  Acct-Link-Count                        | 0-1 | 0   |
  Acct-Session-Time                      | 1   | 0   |
  Acct-Tunnel-Connection                 | 0-1 | 0   |
  Acct-Tunnel-Packets-Lost               | 0-1 | 0   |
  Authorization-Lifetime                 | 0-1 | 0   |
  Callback-Id                            | 0-1 | 0   |
  Callback-Number                        | 0-1 | 0   |
  Called-Station-Id                      | 0-1 | 0   |
  Calling-Station-Id                     | 0-1 | 0   |
  Class                                  | 0+  | 0+  |
  Connection-Info                        | 0+  | 0   |
  Destination-Host                       | 0-1 | 0   |
  Destination-Realm                      | 1   | 0   |
  Event-Timestamp                        | 0-1 | 0-1 |
  Error-Message                          | 0   | 0-1 |
  Error-Reporting-Host                   | 0   | 0-1 |
  Failed-AVP                             | 0   | 0+  |
  ---------------------------------------|-----+-----+








Calhoun, et al.             Standards Track                    [Page 74]

RFC 4005       Diameter Network Access Server Application    August 2005


                                         +-----------+
                                         |  Command  |
                                         |-----+-----+
  Attribute Name                         | ACR | ACA |
  ---------------------------------------|-----+-----+
  Framed-AppleTalk-Link                  | 0-1 | 0   |
  Framed-AppleTalk-Network               | 0-1 | 0   |
  Framed-AppleTalk-Zone                  | 0-1 | 0   |
  Framed-Compression                     | 0-1 | 0   |
  Framed-IP-Address                      | 0-1 | 0   |
  Framed-IP-Netmask                      | 0-1 | 0   |
  Framed-IPv6-Prefix                     | 0+  | 0   |
  Framed-IPv6-Pool                       | 0-1 | 0   |
  Framed-IPX-Network                     | 0-1 | 0   |
  Framed-MTU                             | 0-1 | 0   |
  Framed-Pool                            | 0-1 | 0   |
  Framed-Protocol                        | 0-1 | 0   |
  Framed-Route                           | 0-1 | 0   |
  Framed-Routing                         | 0-1 | 0   |
  NAS-Filter-Rule                        | 0+  | 0   |
  NAS-Identifier                         | 0-1 | 0-1 |
  NAS-IP-Address                         | 0-1 | 0-1 |
  NAS-IPv6-Address                       | 0-1 | 0-1 |
  NAS-Port                               | 0-1 | 0-1 |
  NAS-Port-Id                            | 0-1 | 0-1 |
  NAS-Port-Type                          | 0-1 | 0-1 |
  Origin-AAA-Protocol                    | 0-1 | 0-1 |
  Origin-Host                            | 1   | 1   |
  Origin-Realm                           | 1   | 1   |
  Origin-State-Id                        | 0-1 | 0-1 |
  Originating-Line-Info                  | 0-1 | 0   |
  Proxy-Info                             | 0+  | 0+  |
  QoS-Filter-Rule                        | 0+  | 0   |
  Route-Record                           | 0+  | 0+  |
  Result-Code                            | 0   | 1   |
  Service-Type                           | 0-1 | 0-1 |
  Session-Id                             | 1   | 1   |
  Termination-Cause                      | 0-1 | 0-1 |
  Tunnel-Assignment-Id                   | 0-1 | 0   |
  Tunnel-Client-Endpoint                 | 0-1 | 0   |
  Tunnel-Medium-Type                     | 0-1 | 0   |
  Tunnel-Private-Group-Id                | 0-1 | 0   |
  Tunnel-Server-Endpoint                 | 0-1 | 0   |
  Tunnel-Type                            | 0-1 | 0   |
  User-Name                              | 0-1 | 0-1 |
  Vendor-Specific-Application-Id         | 0-1 | 0-1 |
  ---------------------------------------|-----+-----+




Calhoun, et al.             Standards Track                    [Page 75]

RFC 4005       Diameter Network Access Server Application    August 2005


10.2.2.  Accounting Non-Framed Access AVP Table

  The table in this section is used when the Service-Type specifies
  Non-Framed Access.

                                         +-----------+
                                         |  Command  |
                                         |-----+-----+
  Attribute Name                         | ACR | ACA |
  ---------------------------------------|-----+-----+
  Accounting-Auth-Method                 | 0-1 | 0   |
  Accounting-Input-Octets                | 1   | 0   |
  Accounting-Output-Octets               | 1   | 0   |
  Accounting-Record-Type                 | 1   | 1   |
  Accounting-Record-Number               | 0-1 | 0-1 |
  Accounting-Realtime-Required           | 0-1 | 0-1 |
  Accounting-Sub-Session-Id              | 0-1 | 0-1 |
  Acct-Application-Id                    | 0-1 | 0-1 |
  Acct-Session-Id                        | 1   | 0-1 |
  Acct-Multi-Session-Id                  | 0-1 | 0-1 |
  Acct-Authentic                         | 1   | 0   |
  Acct-Delay-Time                        | 0-1 | 0   |
  Acct-Interim-Interval                  | 0-1 | 0-1 |
  Acct-Link-Count                        | 0-1 | 0   |
  Acct-Session-Time                      | 1   | 0   |
  Authorization-Lifetime                 | 0-1 | 0   |
  Callback-Id                            | 0-1 | 0   |
  Callback-Number                        | 0-1 | 0   |
  Called-Station-Id                      | 0-1 | 0   |
  Calling-Station-Id                     | 0-1 | 0   |
  Class                                  | 0+  | 0+  |
  Connection-Info                        | 0+  | 0   |
  Destination-Host                       | 0-1 | 0   |
  Destination-Realm                      | 1   | 0   |
  Event-Timestamp                        | 0-1 | 0-1 |
  Error-Message                          | 0   | 0-1 |
  Error-Reporting-Host                   | 0   | 0-1 |
  Failed-AVP                             | 0   | 0+  |
  Login-IP-Host                          | 0+  | 0   |
  Login-IPv6-Host                        | 0+  | 0   |
  Login-LAT-Service                      | 0-1 | 0   |
  Login-LAT-Node                         | 0-1 | 0   |
  Login-LAT-Group                        | 0-1 | 0   |
  Login-LAT-Port                         | 0-1 | 0   |
  Login-Service                          | 0-1 | 0   |
  Login-TCP-Port                         | 0-1 | 0   |
  ---------------------------------------|-----+-----+




Calhoun, et al.             Standards Track                    [Page 76]

RFC 4005       Diameter Network Access Server Application    August 2005


                                         +-----------+
                                         |  Command  |
                                         |-----+-----+
  Attribute Name                         | ACR | ACA |
  ---------------------------------------|-----+-----+
  NAS-Identifier                         | 0-1 | 0-1 |
  NAS-IP-Address                         | 0-1 | 0-1 |
  NAS-IPv6-Address                       | 0-1 | 0-1 |
  NAS-Port                               | 0-1 | 0-1 |
  NAS-Port-Id                            | 0-1 | 0-1 |
  NAS-Port-Type                          | 0-1 | 0-1 |
  Origin-AAA-Protocol                    | 0-1 | 0-1 |
  Origin-Host                            | 1   | 1   |
  Origin-Realm                           | 1   | 1   |
  Origin-State-Id                        | 0-1 | 0-1 |
  Originating-Line-Info                  | 0-1 | 0   |
  Proxy-Info                             | 0+  | 0+  |
  QoS-Filter-Rule                        | 0+  | 0   |
  Route-Record                           | 0+  | 0+  |
  Result-Code                            | 0   | 1   |
  Session-Id                             | 1   | 1   |
  Service-Type                           | 0-1 | 0-1 |
  Termination-Cause                      | 0-1 | 0-1 |
  User-Name                              | 0-1 | 0-1 |
  Vendor-Specific-Application-Id         | 0-1 | 0-1 |
  ---------------------------------------|-----+-----+

11.  IANA Considerations

  This section provides guidance to the Internet Assigned Numbers
  Authority (IANA) regarding registration of values related to the
  Diameter protocol, in accordance with BCP 26 [IANAConsid].

  This document defines values in the namespaces that have been created
  and defined in the Diameter Base [BASE].  The IANA Considerations
  section of that document details the assignment criteria.  Values
  assigned in this document, or by future IANA action, must be
  coordinated within this shared namespace.

11.1.  Command Codes

  This specification assigns the value 265 from the Command Code
  namespace defined in [BASE].  See sections 3.1 and 3.2 for the
  assignment of the namespace in this specification.







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RFC 4005       Diameter Network Access Server Application    August 2005


11.2.  AVP Codes

  This specification assigns the values 363 - 366 and 400 - 408 from
  the AVP Code namespace defined in [BASE].  See sections 4 and 5 for
  the assignment of the namespace in this specification.  Note that the
  values 363 - 366 are jointly, but consistently, assigned in
  [DiamMIP].  This document also creates one new namespace to be
  managed by IANA, as described in section 11.5.

  This specification also specifies the use of AVPs in the 0 - 255
  range, which are defined in [RADIUSTypes].  These values are assigned
  by the policy in RFC 2865 section 6 [RADIUS] and are amended by RFC
  3575 [RADIUSIANA].

11.3.  Application Identifier

  This specification uses the value one (1) in the Application
  Identifier namespace as assigned in [BASE].  See section 1.2 above
  for more information.

11.4.  CHAP-Algorithm AVP Values

  As defined in section 5.5, the CHAP-Algorithm AVP (AVP Code 403) uses
  the values of the "PPP AUTHENTICATION ALGORITHMS" namespace defined
  in [PPPCHAP].

11.5.  Accounting-Auth-Method AVP Values

  As defined in section 8.6, the Accounting-Auth-Method AVP (AVP Code
  406) defines the values 1 - 5.  All remaining values are available
  for assignment via IETF Consensus [IANA].

11.6.  Origin-AAA-Protocol AVP Values

  As defined in section 9.3.6, the Origin-AAA-Protocol AVP (AVP Code
  408) defines the value 1. All remaining values are available for
  assignment with a "Specification Required" policy [IANAConsid].

12.  Security Considerations

  This document describes the extension of Diameter for the NAS
  application.  The security considerations of the Diameter protocol
  itself have been discussed in [BASE].  Use of this application of
  Diameter MUST take into consideration the security issues and
  requirements of the Base protocol.






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  This document does not contain a security protocol but does discuss
  how PPP authentication protocols can be carried within the Diameter
  protocol.  The PPP authentication protocols described are PAP and
  CHAP.

  The use of PAP SHOULD be discouraged, as it exposes users' passwords
  to possibly non-trusted entities.  However, PAP is also frequently
  used for use with One-Time Passwords, which do not expose a security
  risk.

  This document also describes how CHAP can be carried within the
  Diameter protocol, which is required for RADIUS backward
  compatibility.  The CHAP protocol, as used in a RADIUS environment,
  facilitates authentication replay attacks.

  The use of the EAP authentication protocols described in [DiamEAP]
  can offer better security, given a method suitable for the
  circumstances.

13.  References

13.1.  Normative References

  [BASE]         Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and
                 J. Arkko, "Diameter Base Protocol", RFC 3588,
                 September 2003.

  [DiamTrans]    Aboba, B. and J. Wood, "Authentication, Authorization
                 and Accounting (AAA) Transport Profile", RFC 3539,
                 June 2003.

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

  [RADIUSTypes]  IANA, "RADIUS Types", URL:
                 <http://www.iana.org/assignments/radius-types>

  [RADIUSIPv6]   Aboba, B., Zorn, G., and D. Mitton, "RADIUS and IPv6",
                 RFC 3162, August 2001.

  [IPv6Addr]     Nerenberg, L., "IMAP4 Binary Content Extension", RFC
                 3516, April 2003.

  [PPPCHAP]      Simpson, W., "PPP Challenge Handshake Authentication
                 Protocol (CHAP)", RFC 1994, August 1996.





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RFC 4005       Diameter Network Access Server Application    August 2005


  [IANAConsid]   Narten, T. and H. Alvestrand, "Guidelines for Writing
                 an IANA Considerations Section in RFCs", BCP 26, RFC
                 2434, October 1998.

  [IANA]         IANA Assigned Numbers Database, URL:
                 <http://www.iana.org/numbers.html>

  [Keywords]     Bradner, S., "Key words for use in RFCs to Indicate
                 Requirement Levels", BCP 14, RFC 2119, March 1997.

  [ANITypes]     NANPA Number Resource Info, ANI Assignments, URL:
                 <http://www.nanpa.com/number_resource_info/
                 ani_ii_assignments.html>

13.2.  Informative References

  [RADIUSAcct]   Rigney, C., "RADIUS Accounting", RFC 2866, June 2000.

  [RADIUSExt]    Rigney, C., Willats, W., and P. Calhoun, "RADIUS
                 Extensions", RFC 2869, June 2000.

  [RADTunnels]   Zorn, G., Leifer, D., Rubens, A., Shriver, J.,
                 Holdrege, M., and I. Goyret, "RADIUS Attributes for
                 Tunnel Protocol Support", RFC 2868, June 2000.

  [RADTunlAcct]  Zorn, G., Aboba, B., and D. Mitton, "RADIUS Accounting
                 Modifications for Tunnel Protocol Support", RFC 2867,
                 June 2000.

  [RADDynAuth]   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.

  [RADIUSIANA]   Aboba, B., "IANA Considerations for RADIUS (Remote
                 Authentication Dial In User Service)", RFC 3575, July
                 2003.

  [NASModel]     Mitton, D. and M. Beadles, "Network Access Server
                 Requirements Next Generation (NASREQNG) NAS Model",
                 RFC 2881, July 2000.

  [NASCriteria]  Beadles, M. and D. Mitton, "Criteria for Evaluating
                 Network Access Server Protocols", RFC 3169, September
                 2001.






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RFC 4005       Diameter Network Access Server Application    August 2005


  [AAACriteria]  Aboba, B., Calhoun, P., Glass, S., Hiller, T., McCann,
                 P., Shiino, H., Zorn, G., Dommety, G., Perkins, C.,
                 Patil, B., Mitton, D., Manning, S., Beadles, M.,
                 Walsh, P., Chen, X., Sivalingham, S., Hameed, A.,
                 Munson, M., Jacobs, S., Lim, B., Hirschman, B., Hsu,
                 R., Xu, Y., Campbell, E., Baba, S., and E. Jaques,
                 "Criteria for Evaluating AAA Protocols for Network
                 Access", RFC 2989, November 2000.

  [DiamEAP]      Eronen, P., "Diameter EAP Application", Work in
                 Progress, May 2004.

  [DiamCMS]      Calhoun, P., Bulley, W., and S. Farrell, "Diameter CMS
                 Security Application", Work in Progress, March 2002.

  [DiamMIP]      Calhoun, P., Johansson, T., Perkins, C., Hiller, T.,
                 and P. McCann "Diameter Mobile IPv4 Application", RFC
                 4004, August 2005.

  [VSA]          Mitton, D., "Diameter/RADIUS Vendor Specific AVP
                 Translation", Work in Progress, April 2005.

  [RAD802.1X]    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.

  [CDMA2000]     3GPP2 "P.S0001-B", Wireless IP Network Standard,
                 October 2002.
                 http://www.3gpp2.com/Public_html/specs/P.S0001-
                 B_v1.0.pdf

  [AppleTalk]    Sidhu, Gursharan; Andrews, Richard F. & Oppenheimer,
                 Alan B.  "Inside AppleTalk", Second Edition, Apple
                 Computer., 1990

  [ARAP]         Apple Remote Access Protocol (ARAP) Version 2.0
                 External Reference Specification", Apple Computer,
                 September 1994, R0612LL/B

  [IPX]          Novell, Inc., "NetWare System Technical Interface
                 Overview", June 1989,  # 883-000780-001

  [LAT]          Local Area Transport (LAT) Specification V5.0, Digital
                 Equipment Corp., AA-NL26A-TE, June 1989






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  [DIFFSERV]     Nichols, K., Blake, S., Baker, F., and D. Black,
                 "Definition of the Differentiated Services Field (DS
                 Field) in the IPv4 and IPv6 Headers", RFC 2474,
                 December 1998.

  [DIFFSERVAF]   Heinanen, J., Baker, F., Weiss, W., and J. Wroclawski,
                 "Assured Forwarding PHB Group", RFC 2597, June 1999.

  [DIFFSERVEF]   Davie, B., Charny, A., Bennet, J.C., Benson, K., Le
                 Boudec, J., Courtney, W., Davari, S., Firoiu, V., and
                 D. Stiliadis, "An Expedited Forwarding PHB (Per-Hop
                 Behavior)", RFC 3246, March 2002.

  [UTF-8]        Yergeau, F., "UTF-8, a transformation format of ISO
                 10646", STD 63, RFC 3629, November 2003.

  [ISOLatin]     ISO 8859. International Standard -- Information
                 Processing -- 8-bit Single-Byte Coded Graphic
                 Character Sets -- Part 1: Latin Alphabet No. 1, ISO
                 8859-1:1987.  URL:
                 <http://www.iso.ch/cate/d16338.html>

  [PPP]          Simpson, W., "The Point-to-Point Protocol (PPP)", STD
                 51, RFC 1661, July 1994.

  [PAP]          Lloyd, B. and W. Simpson, "PPP Authentication
                 Protocols", RFC 1334, October 1992.

  [L2TP]         Townsley, W., Valencia, A., Rubens, A., Pall, G.,
                 Zorn, G., and B. Palter, "Layer Two Tunneling Protocol
                 "L2TP"", RFC 2661, August 1999.

  [PPPMP]        Sklower, K., Lloyd, B., McGregor, G., Carr, D., and T.
                 Coradetti, "The PPP Multilink Protocol (MP)", RFC
                 1990, August 1996.

  [PPTP]         Hamzeh, K., Pall, G., Verthein, W., Taarud, J.,
                 Little, W., and G. Zorn, "Point-to-Point Tunneling
                 Protocol", RFC 2637, July 1999.

  [IEEE 802.11F] IEEE, "Trial-Use Recommended Practice for Multi-Vendor
                 Access Point Interoperability via an Inter-Access
                 Point Protocol Across Distribution Systems Supporting
                 IEEE 802.11 Operation", IEEE 802.11F-2003, June 2003.







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14.  Acknowledgements

  The authors would like to thank Carl Rigney, Allan C. Rubens, William
  Allen Simpson, and Steve Willens for their work on the original
  RADIUS [RADIUS], from which many of the concepts in this
  specification were derived.  Thanks, also, to Carl Rigney for
  [RADIUSAcct] and [RADIUSExt]; Ward Willats for [RADIUSExt]; Glen
  Zorn, Bernard Aboba, and Dave Mitton for [RADTunlAcct] and
  [RADIUSIPv6]; and Dory Leifer, John Shriver, Matt Holdrege, and
  Ignacio Goyret for their work on [RADTunnels].  This document stole
  text and concepts from both [RADTunnels] and [RADIUSExt].  Thanks go
  to Carl Williams for providing IPv6-specific text.

  The authors would also like to acknowledge the following people for
  their contributions in the development of the Diameter protocol:
  Bernard Aboba, Jari Arkko, William Bulley, Kuntal Chowdhury, Daniel
  C. Fox, Lol Grant, Nancy Greene, Jeff Hagg, Peter Heitman, Paul
  Krumviede, Fergal Ladley, Ryan Moats, Victor Muslin, Kenneth Peirce,
  Sumit Vakil, John R. Vollbrecht, and Jeff Weisberg.

  Finally, Pat Calhoun would like to thank Sun Microsystems, as most of
  the effort put into this document was done while he was in their
  employ.




























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Authors' Addresses

  Pat Calhoun
  Cisco Systems, Inc.
  170 West Tasman Drive
  San Jose, CA 95134
  USA

  Phone: +1 408-853-5269
  EMail: [email protected]


  Glen Zorn
  Cisco Systems, Inc.
  500 108th Avenue N.E., Suite 500
  Bellevue, WA 98004
  USA

  Phone:  1 425-471-4861
  EMail: [email protected]


  David Spence
  3259 Bluett Rd.
  Ann Arbor, MI  48105
  USA

  Phone: +1 734 834 6481
  EMail: [email protected]


  David Mitton
  Circular Networks
  733 Turnpike St #154
  North Andover, MA 01845

  EMail: [email protected]














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Full Copyright Statement

  Copyright (C) The Internet Society (2005).

  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.

  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,
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Acknowledgement

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







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