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AAA Working Group                                         Pat R. Calhoun
Internet-Draft                                    Sun Microsystems, Inc.
Category: Standards Track                                 William Bulley
<draft-ietf-aaa-diameter-nasreq-04.txt>              Merit Network, Inc.
                                                         Allan C. Rubens
                                                       Tut Systems, Inc.
                                                               Jeff Haag
                                                               Glen Zorn
                                                     Cisco Systems, Inc.
                                                                May 2001



                       Diameter NASREQ Extensions



Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.  Internet-Drafts are working
   documents of the Internet Engineering Task Force (IETF), its areas,
   and its working groups.  Note that other groups may also distribute
   working documents as Internet-Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at:

      http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at:

      http://www.ietf.org/shadow.html.

   This document is an individual contribution for consideration by the
   AAA Working Group of the Internet Engineering Task Force.  Comments
   should be submitted to the diameter@diameter.org mailing list.

   Distribution of this memo is unlimited.

   Copyright   (C) The Internet Society 2001.  All Rights Reserved.






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Abstract

   This document describes the Diameter extension that is used for AAA
   in a PPP/SLIP Dial-Up and Terminal Server Access environment.  This
   extension, combined with the base protocol, satisfies the
   requirements defined in the NASREQ AAA criteria specification and the
   ROAMOPS AAA Criteria specification.

   Given that it is expected that initial deployments of the Diameter
   protocol in a dial-up environment will include legacy systems, this
   extension was carefully designed to ease the burden of servers that
   must perform protocol conversion between RADIUS and Diameter.  This
   is achieved by re-using the RADIUS address space, eliminating the
   need to perform attribute lookups.


Table of Contents

      1.0  Introduction
            1.1  Requirements language
            1.2  Advertising extension support
      2.0  Supported AVPs
            2.1  Diameter AVPs
                  2.1.1  Request-Type AVP
                  2.1.2  Filter-Rule AVP
            2.2  Legacy RADIUS Attributes
                  2.2.1  NAS-IP-Address AVP
                  2.2.2  NAS-Identifier AVP
                  2.2.3  State AVP
                  2.2.4  Class AVP
      3.0  Legacy RADIUS Authentication Support
            3.1  Command-Codes Values
                  3.1.1  AA-Request (AAR) Command
                        3.1.1.1  User-Password AVP
                        3.1.1.2  CHAP-Password AVP
                        3.1.1.3  CHAP-Challenge AVP
                        3.1.1.4  ARAP-Password AVP
                  3.1.2  AA-Answer (AAA) Command
                        3.1.2.1  ARAP-Challenge-Response AVP
                        3.1.2.2  Password-Retry AVP
                  3.1.3  AA-Challenge-Ind (ACI) Command
                        3.1.3.1  Prompt AVP
            3.2  Reply-Message AVP
      4.0  Extensible Authentication Protocol Support
            4.1  Alternative Uses
            4.2  Command-Codes Values
                  4.2.1  Diameter-EAP-Request (DER) Command
                  4.2.2  Diameter-EAP-Answer (DEA) Command



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                  4.2.3  Diameter-EAP-Ind (DEI) Command
            4.3  EAP-Payload AVP
      5.0  Diameter Session Termination
      6.0  Call and Session Information
            6.1  NAS-Port AVP
            6.2  Filter-Id AVP
            6.3  Callback-Number AVP
            6.4  Callback-Id AVP
            6.5  Idle-Timeout AVP
            6.6  Called-Station-Id AVP
            6.7  Calling-Station-Id AVP
            6.8  NAS-Port-Type AVP
            6.9  Port-Limit AVP
            6.10 Connect-Info AVP
      7.0  Service Specific Authorization AVPs
            7.1  Service-Type AVP
            7.2  Framed Access Authorization AVPs
                  7.2.1  Framed-Protocol AVP
                  7.2.2  Framed-Routing AVP
                  7.2.3  Framed-MTU AVP
                  7.2.4  Framed-Compression AVP
                  7.2.5  IP Access
                        7.2.5.1  Framed-IP-Address AVP
                        7.2.5.2  Framed-IP-Netmask AVP
                        7.2.5.3  Framed-IP-Route AVP
                  7.2.6  IPX Access
                  7.2.6.1  Framed-IPX-Network AVP
                  7.2.7  Appletalk Access
                        7.2.7.1  Framed-AppleTalk-Link AVP
                        7.2.7.2  Framed-AppleTalk-Network AVP
                        7.2.7.3  Framed-AppleTalk-Zone AVP
                  7.2.8  ARAP Access
                        7.2.8.1  ARAP-Features AVP
                        7.2.8.2  ARAP-Zone-Access AVP
                        7.2.8.3  ARAP-Security AVP
                        7.2.8.4  ARAP-Security-Data AVP
            7.3  Non-Framed Access Authorization AVPs
                  7.3.1  Login-IP-Host AVP
                  7.3.2  Login-Service AVP
                  7.3.3  TCP Services
                        7.3.3.1  Login-TCP-Port AVP
                  7.3.4  LAT Services
                        7.3.4.1  Login-LAT-Service AVP
                        7.3.4.2  Login-LAT-Node AVP
                        7.3.4.3  Login-LAT-Group AVP
                        7.3.4.4  Login-LAT-Port AVP
            7.4  Tunneling AVP
                        7.4.1  Tunnel-Type AVP



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                        7.4.2  Tunnel-Medium-Type AVP
                        7.4.3  Tunnel-Client-Endpoint AVP
                        7.4.4  Tunnel-Server-Endpoint AVP
                        7.4.5  Tunnel-Password AVP
                        7.4.6  Tunnel-Private-Group-ID AVP
                        7.4.7  Tunnel-Assignment-ID AVP
                        7.4.8  Tunnel-Preference AVP
                        7.4.9  Tunnel-Client-Auth-ID AVP
                        7.4.10 Tunnel-Server-Auth-ID AVP
      8.0  Accounting Considerations
            8.1  Accounting-Input-Octets AVP
            8.2  Accounting-Output-Octets AVP
            8.3  Accounting-Session-Time AVP
            8.4  Accounting-Input-Packets AVP
            8.5  Accounting-Output-Packets AVP
            8.6  Accounting-Authentication-Type AVP
            8.7  Acct-Tunnel-Connection AVP
            8.8  Acct-Tunnel-Packets-Lost AVP
      9.0  Interactions with Resource Management
      10.0  RADIUS/Diameter Protocol Interactions
            10.1  RADIUS request forwarded as Diameter request
            10.2  Diameter request forwarded as RADIUS request
      11.0  AVP Occurrence Table
            11.1  NASREQ Command AVP Table
            11.2  Accounting AVP Table
                  11.2.1  Framed Access
                  11.2.2  Non-Framed Access
      12.0  IANA Considerations
            12.1  Command Codes
            12.2  AVP Codes
            12.3  Request-Type AVP Values
            12.4  Extension Identifier
      13.0  Security Considerations
      14.0  References
      15.0  Acknowledgements
      16.0  Authors' Addresses
      17.0  Full Copyright Statement
      18.0  Expiration Date


1.0  Introduction

   This document describes the Diameter extension that is used for AAA
   in a PPP/SLIP Dial-Up and Terminal Server Access environment.  This
   extension, combined with the base protocol [2], satisfies the
   requirements defined in the NASREQ AAA criteria specification [24]
   and the ROAMOPS AAA Criteria specification [4].




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   This document is divided into three main sections. The first section
   defines the Diameter Command-Codes and AVPs that are needed to
   support legacy authentication protocols, those that are typically
   supported by RADIUS [1] servers. The second section defines the
   Command-Codes and AVPs necessary for a Diameter node to support PPP's
   Extensible Authentication Protocol (EAP) [25].  The third section
   contains the Authorization AVPs that are needed for the various
   services offered by a NAS, such as PPP dial-in, terminal server and
   tunneling applications, such as L2TP [16].

   Given that it is expected that initial deployments of the Diameter
   protocol in a dial-up environment will include legacy systems, this
   extension was carefully designed to ease the burden of servers that
   must perform protocol conversion between RADIUS and Diameter.  This
   is achieved by re-using the RADIUS address space, eliminating the
   need to perform attribute lookups.

   The value assigned for the Extension-Id [2] AVP is one (1).


1.1  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 [12].


1.2  Advertising extension support

   Diameter nodes conforming to this specification MAY advertise support
   by including the value of one (1) in either the Device-Reboot-Ind
   Command's [2] Auth-Extension-Id or Acct-Extension-Id AVPs.


2.0  Supported AVPs

   This section lists all of the Diameter AVPs and the legacy RADIUS
   attributes supported by this extension.


2.1  Diameter AVPs

   This section will define all of the AVPs that are not backward
   compatible with the RADIUS protocol [1]. A Diameter message that
   includes one of these AVPs MAY cause interoperability issues should
   the request traverse a AAA node that only supports the RADIUS
   protocol. However, the Diameter protocol SHOULD NOT be hampered from
   future developments due to the existing installed base.



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   The following table describes the Diameter AVPs defined in the NASREQ
   extension, their AVP Code values, types, possible flag values and
   whether the AVP MAY be encrypted.

                                            +---------------------+
                                            |    AVP Flag rules   |
                                            |----+-----+----+-----|----+
                   AVP  Section             |    |     |SHLD| MUST|MAY |
   Attribute Name  Code Defined  Value Type |MUST| MAY | NOT|  NOT|Encr|
   -----------------------------------------|----+-----+----+-----|----|
   EAP-Payload      402  4.3     OctetString| M  |  P  |    |  V  | Y  |
   Filter-Rule      400  2.1.2   OctetString| M  |  P  |    |  V  | Y  |
   Request-Type     401  2.1.1   Unsigned32 | M  |  P  |    |  V  | N  |
   Tunneling        403  7.4     Grouped    | M  |  P  |    |  V  | N  |


2.1.1  Request-Type AVP

   The Request-Type AVP (AVP Code 401) is of type Unsigned32 and is used
   to determine the type of request being transmitted. Note that a
   request with this AVP set to a value other than
   AUTHORIZE_AUTHENTICATE MAY break backward RADIUS compatibility. The
   following values are defined:

      AUTHENTICATE_ONLY          1
         The request being sent is for authentication only, and MUST
         contain the relevant authentication AVPs that are needed by the
         Diameter server to authenticate the user.

      AUTHORIZE_ONLY             2
         The request being sent is for authorization only, and MUST
         contain the authorization AVPs that are necessary to identify
         the service being requested/offered.

      AUTHORIZE_AUTHENTICATE     3
         The request contains a request for both authentication and
         authorization. The request MUST include both the relevant
         authentication information, and authorization information
         necessary to identify the service being requested/offered.


2.1.2  Filter-Rule AVP

   The Filter-Rule AVP (AVP Code 400) is of type OctetString, encoded in
   the UTF-8 [29] format, and provides 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.




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   Each packet can be filtered based on the following information that
   is associated with it:

      Direction                          (in or out)
      Source and destination IP address  (possibly masked)
      Protocol
      Source and destination port        (lists or ranges)
      TCP flags
      IP fragment flag
      IP options
      ICMP types

   Rules for the appropriate direction are evaluated in order, with the
   first matched rule terminating the evaluation.  Each packet is
   evaluated once. If no rule matches, the packet is dropped if the last
   rule evaluated was a permit, and passed if the last rule was a deny.

   The filters in the Filter-Rule AVP MUST follow the format:

      action dir proto from src to dst [options]

      action       permit - Allow packets that match the rule.
                   deny - Drop packets that match the rule.

      dir          "in" is from the terminal, "out" is to the terminal.

      proto        An IP protocol specified by number.  The "ip" keyword
                   means any protocol will match.

      src and dst  <address/mask> [ports]

                   The <address/mask> may be specified as:
                   ipno       An IPv4 or IPv6 number in dotted-quad or
                              canonical IPv6 form. Only this exact IP
                              number will match the rule.
                   ipno/bits  An IP number as above with a mask width of
                              the form 1.2.3.4/24.  In this case all IP
                              numbers from 1.2.3.0 to 1.2.3.255 will
                              match.  The bit width MUST be valid for
                              the IP version and the IP number MUST NOT
                              have bits set beyond the mask.

                   The sense of the match can be inverted by preceding
                   an address with the not modifier, causing all other
                   addresses to be matched instead.  This does not
                   affect the selection of port numbers.

                      The keyword "any" is 0.0.0.0/0 or the IPv6



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                      equivalent.  The keyword "assigned" is the address
                      or set of addresses assigned to the terminal.  The
                      first rule SHOULD be "deny in ip !assigned".

                   With the TCP and UDP protocols, optional ports may be
                   specified as:

                      {port|port-port}[,port[,...]]

                   The `-' notation specifies a range of ports
                   (including boundaries).

                   Fragmented packets which have a non-zero offset (i.e.
                   not the first fragment) will never match a rule which
                   has one or more port specifications.  See the frag
                   option for details on matching fragmented packets.

      options:
         frag    Match if the packet is a fragment and this is not the
                 first fragment of the datagram.  frag may not be used
                 in conjunction with either tcpflags or TCP/UDP port
                 specifications.

         ipoptions spec
                 Match if the IP header contains the comma separated
                 list of options specified in spec. The supported IP
                 options are:

                 ssrr (strict source route), lsrr (loose source route),
                 rr (record packet route) and ts (timestamp). The
                 absence of a particular option may be denoted with a
                 `!'.

         tcpoptions spec
                 Match if the TCP header contains the comma separated
                 list of options specified in spec. The supported TCP
                 options are:

                 mss (maximum segment size), window (tcp window
                 advertisement), sack (selective ack), ts (rfc1323
                 timestamp) and cc (rfc1644 t/tcp connection count).
                 The absence of a particular option may be denoted with
                 a `!'.

         established
                 TCP packets only. Match packets that have the RST or
                 ACK bits set.




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         setup   TCP packets only. Match packets that have the SYN bit
                 set but no ACK bit.

         tcpflags spec
                 TCP packets only. Match if the TCP header contains the
                 comma separated list of flags specified in spec. The
                 supported TCP flags are:

                 fin, syn, rst, psh, ack and urg. The absence of a
                 particular flag may be denoted with a `!'. A rule which
                 contains a tcpflags specification can never match a
                 fragmented packet which has a non-zero offset.  See the
                 frag option for details on matching fragmented packets.

         icmptypes types
                 ICMP packets only.  Match if the ICMP type is in the
                 list types. The list may be specified as any
                 combination of ranges or individual types separated by
                 commas.  The supported ICMP types are:

                 echo reply (0), destination unreachable (3), source
                 quench (4), redirect (5), echo request (8), router
                 advertisement (9), router solicitation (10), time-to-
                 live exceeded (11), IP header bad (12), timestamp
                 request (13), timestamp reply (14), information request
                 (15), information reply (16), address mask request (17)
                 and address mask reply (18).

   There is one kind of packet that the NAS MUST always discard, that is
   an IP fragment with a fragment offset of one.  This is a valid
   packet, but it only has one use, to try to circumvent firewalls.

      A NAS that is unable to interpret or apply a deny rule MUST
      terminate the session.  A NAS that is unable to interpret or apply
      a permit rule MAY apply a more restrictive rule.  A NAS MAY apply
      deny rules of its own before the supplied rules, for example to
      protect the NAS owner's infrastructure.

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


2.2  Legacy RADIUS Attributes

   The Diameter protocol reserves the first 255 AVP identifiers for
   "legacy RADIUS" support. The following table contains the RADIUS
   attributes supported by this Diameter extension, their AVP code
   values, types, possible flag values and whether the AVP MAY be



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   encrypted. RADIUS attributes not listed are not supported by the
   Diameter protocol.


                                            +---------------------+
                                            |    AVP Flag rules   |
                                            |----+-----+----+-----|----+
                   AVP  Section             |    |     |SHLD| MUST|MAY |
   Attribute Name  Code Defined  Value Type |MUST| MAY | NOT|  NOT|Encr|
   -----------------------------------------|----+-----+----+-----|----|
   Accounting-       45  8.6     Unsigned32 |    |  P  |    |  V  | Y  |
     Authentication-Type                    |    |     |    |     |    |
   Accounting-Input- 42  8.1     Unsigned32 |    |  P  |    |  V  | Y  |
     Octets                                 |    |     |    |     |    |
   Accounting-Input- 47  8.4     Unsigned32 |    |  P  |    |  V  | Y  |
     Packets                                |    |     |    |     |    |
   Accounting-       43  8.2     Unsigned32 |    |  P  |    |  V  | Y  |
     Output-Octets                          |    |     |    |     |    |
   Accounting-       48  8.5     Unsigned32 |    |  P  |    |  V  | Y  |
     Output-Packets                         |    |     |    |     |    |
   Accounting-       46  8.3     Unsigned32 |    |  P  |    |  V  | Y  |
     Session-Time                           |    |     |    |     |    |
   Acct-Tunnel-      68  8.7     OctetString|    |  P  |    |  V  | Y  |
     Connection                             |    |     |    |     |    |
   Acct-Tunnel-      86  8.8     OctetString|    |  P  |    |  V  | Y  |
     Packets-Lost                           |    |     |    |     |    |
   ARAP-Challenge-   84  3.1.2.1 OctetString| M  |  P  |    |  V  | Y  |
     Response                               |    |     |    |     |    |
   ARAP-Features     71  7.2.8.1 OctetString| M  |  P  |    |  V  | Y  |
   ARAP-Password     70  3.1.1.4 OctetString| M  |  P  |    |  V  | Y  |
   ARAP-Security     73  7.2.8.3 Unsigned32 | M  |  P  |    |  V  | Y  |
   ARAP-Security-    74  7.2.8.4 OctetString| M  |  P  |    |  V  | Y  |
     Data                                   |    |     |    |     |    |
   ARAP-Zone-Access  72  7.2.8.2 Unsigned32 | M  |  P  |    |  V  | Y  |
   Callback-Id       20  6.4     OctetString| M  |  P  |    |  V  | Y  |
   Callback-Number   19  6.3     OctetString| M  |  P  |    |  V  | Y  |
   Called-Station-Id 30  6.6     OctetString| M  |  P  |    |  V  | Y  |
   Calling-Station-  31  6.7     OctetString| M  |  P  |    |  V  | Y  |
     Id                                     |    |     |    |     |    |
   CHAP-Challenge    60  3.1.1.3 OctetString| M  |  P  |    |  V  | Y  |
   CHAP-Password      3  3.1.1.2 OctetString| M  |  P  |    |  V  | Y  |
   Class             25  2.2.4   OctetString| M  |  P  |    |  V  | Y  |
   Connect-Info      77  6.10    OctetString|    |  P  |    |  V  | Y  |
   Filter-Id         11  6.2     OctetString| M  |  P  |    |  V  | Y  |
   Framed-Appletalk- 37  7.2.7.1 Unsigned32 | M  |  P  |    |  V  | Y  |
     Link                                   |    |     |    |     |    |





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                                            +---------------------+
                                            |    AVP Flag rules   |
                                            |----+-----+----+-----|----+
                   AVP  Section             |    |     |SHLD| MUST|MAY |
   Attribute Name  Code Defined  Value Type |MUST| MAY | NOT|  NOT|Encr|
   -----------------------------------------|----+-----+----+-----|----|
   Framed-Appletalk- 38  7.2.7.2 Unsigned32 | M  |  P  |    |  V  | Y  |
     Network                                |    |     |    |     |    |
   Framed-Appletalk- 39  7.2.7.3 OctetString| M  |  P  |    |  V  | Y  |
     Zone                                   |    |     |    |     |    |
   Framed-Protocol    7  7.2.1   Unsigned32 | M  |  P  |    |  V  | Y  |
   Framed-IP-Address  8  7.2.5.1 Address    | M  |  P  |    |  V  | Y  |
   Framed-           13  7.2.4   Unsigned32 | M  |  P  |    |  V  | Y  |
     Compression                            |    |     |    |     |    |
   Framed-IP-Netmask  9  7.2.5.2 Address    | M  |  P  |    |  V  | Y  |
   Framed-IP-Route   22  7.2.5.3 OctetString| M  |  P  |    |  V  | Y  |
   Framed-IPX-       23  7.2.6.1 OctetString| M  |  P  |    |  V  | Y  |
     Network                                |    |     |    |     |    |
   Framed-MTU        12  7.2.3   Unsigned32 | M  |  P  |    |  V  | Y  |
   Framed-Routing    10  7.2.2   Unsigned32 | M  |  P  |    |  V  | Y  |
   Idle-Timeout      28  6.5     Unsigned32 | M  |  P  |    |  V  | Y  |
   Login-IP-Host     14  7.3.1   Address    | M  |  P  |    |  V  | Y  |
   Login-LAT-Group   36  7.3.4.3 OctetString| M  |  P  |    |  V  | Y  |
   Login-LAT-Node    35  7.3.4.2 OctetString| M  |  P  |    |  V  | Y  |
   Login-LAT-Port    63  7.3.4.4 OctetString| M  |  P  |    |  V  | Y  |
   Login-LAT-Service 34  7.3.4.1 Unsigned32 | M  |  P  |    |  V  | Y  |
   Login-Service     15  7.3.2   Unsigned32 | M  |  P  |    |  V  | Y  |
   Login-TCP-Port    16  7.3.3.1 Unsigned32 | M  |  P  |    |  V  | Y  |
   NAS-Identifier    32  2.2.2   OctetString| M  |  P  |    |  V  | Y  |
   NAS-IP-Address     4  2.2.1   Address    | M  |  P  |    |  V  | Y  |
   NAS-Port           5  6.1.1   Unsigned32 | M  |  P  |    |  V  | Y  |
   NAS-Port-Type     61  6.8     Unsigned32 | M  |  P  |    |  V  | Y  |
   Password-Retry    75  3.1.2.2 Unsigned32 |    |  P  |    |  V  | Y  |
   Port-Limit        62  6.9     Unsigned32 | M  |  P  |    |  V  | Y  |
   Prompt            76  3.1.3.1 Unsigned32 |    |  P  |    |  V  | Y  |
   Reply-Message     18  3.2     OctetString| M  |  P  |    |  V  | Y  |
   Service-Type       6  7.1     Unsigned32 | M  |  P  |    |  V  | Y  |
   State             24  2.2.3   OctetString| M  |  P  |    |  V  | Y  |
   Tunnel-           82  7.4.7   OctetString| M  |  P  |    |  V  | Y  |
     Assignment-Id                          |    |     |    |     |    |
   Tunnel-Client-    90  7.4.9   OctetString| M  |  P  |    |  V  | Y  |
     Auth-ID                                |    |     |    |     |    |
   Tunnel-Client-    66  7.4.3   OctetString| M  |  P  |    |  V  | Y  |
     Endpoint                               |    |     |    |     |    |
   Tunnel-Medium-    65  7.4.2   Unsigned32 | M  |  P  |    |  V  | Y  |
     Type                                   |    |     |    |     |    |
   Tunnel-Password   69  7.4.5   OctetString| M  |  P  |    |  V  | Y  |




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                                            +---------------------+
                                            |    AVP Flag rules   |
                                            |----+-----+----+-----|----+
                   AVP  Section             |    |     |SHLD| MUST|MAY |
   Attribute Name  Code Defined  Value Type |MUST| MAY | NOT|  NOT|Encr|
   -----------------------------------------|----+-----+----+-----|----|
   Tunnel-Preference 83  7.4.8   Unsigned32 | M  |  P  |    |  V  | Y  |
   Tunnel-Private-   81  7.4.6   OctetString| M  |  P  |    |  V  | Y  |
     Group-ID                               |    |     |    |     |    |
   Tunnel-Server-    91  7.4.10  OctetString| M  |  P  |    |  V  | Y  |
     Auth-ID                                |    |     |    |     |    |
   Tunnel-Server-    67  7.4.4   OctetString| M  |  P  |    |  V  | Y  |
     Endpoint                               |    |     |    |     |    |
   Tunnel-Type       64  7.4.1   Unsigned32 | M  |  P  |    |  V  | Y  |
   User-Password      2  3.1.1.1 OctetString| M  |  P  |    |  V  | Y  |

   The AVPs defined in this section SHOULD only used when a
   Diameter/RADIUS gateway function is invoked, and are not used in the
   Diameter protocol.


2.2.1  NAS-IP-Address AVP

   The NAS-IP-Address AVP (AVP Code 4) [1] is of type Address, and
   contains the IP Address of the NAS providing service to the user.
   When this AVP is present, the Origin-FQDN AVP DOES NOT represent the
   NAS providing service to the user. Note that this AVP SHOULD only
   added by a RADIUS/Diameter protocol gateway (see Section 10.0).


2.2.2  NAS-Identifier AVP

   The NAS-Identifier AVP (AVP Code 32) [1] is of type OctetString,
   encoded in the UTF-8 [29] format, and contains the Identity of the
   NAS providing service to the user. When this AVP is present, the
   Origin-FQDN AVP DOES NOT represent the NAS providing service to the
   user. Note that this AVP SHOULD only added by a RADIUS/Diameter
   protocol gateway (see Section 10.0).


2.2.3  State AVP

   The State AVP (AVP Code 24) is of type OctetString and is used to
   transmit the contents of the RADIUS State attribute, and no
   interpretation of the  contents should be made.  Note that this AVP
   SHOULD only added by a RADIUS/Diameter protocol gateway (see Section
   10.0).




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2.2.4  Class AVP

   The Class AVP (AVP Code 25) is of type OctetString and is used to
   transmit the contents of the RADIUS Class attribute, and no
   interpretation of the contents should be made.  Note that this AVP
   SHOULD only added by a RADIUS/Diameter protocol gateway (see Section
   10.0).


3.0  Legacy RADIUS Authentication Support

   This section defines the new Command-Code [2] values required to
   support the legacy authentication protocols (i.e. PAP, CHAP), as well
   as the AVPs that are 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 [2].

   Unlike the RADIUS protocol [1], the Diameter protocol does not
   require authentication information to be contained in a request from
   the client. Therefore, it is possible to send a request for
   authorization only. The type of service depends upon the Request-Type
   AVP. This difference MAY cause operational issues in environments
   that need RADIUS interoperability, and it MAY be necessary that
   protocol conversion gateways add some authentication information when
   transmitting to a RADIUS server.

   The Diameter protocol allows for users to be periodically re-
   authenticated and/or re-authorized. 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. A Diameter server
   informs the NAS of the authorized session lifetime via the Session-
   Timeout AVP [1].

   A NAS MUST re-authenticate and/or authorize after the period provided
   by the server. Furthermore, it is possible for Diameter servers to
   issue an unsolicited re-authentication and/or re-authorization by
   issuing an AA-Challenge-Ind message to the NAS. Upon receipt of such
   a message, the NAS is instructed to issue a request to re-
   authenticate and/or re-authorize the client.


3.1  Command-Codes Values

   This section defines new Command-Code [2] values that MUST be
   supported by all Diameter implementations that conform to this
   specification. The following Command Codes are defined in this
   section:



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      Command-Name             Abbrev.    Code       Reference
      --------------------------------------------------------
      AA-Answer                 AAA       265          3.1.2
      AA-Challenge-Ind          ACI       267          3.1.3
      AA-Request                AAR       265          3.1.1


3.1.1  AA-Request (AAR) Command

   The AA-Request message (AAR), indicated by the Command-Code field set
   to 265 and the 'R' bit set in the message flags field, is used in
   order to request authentication and/or authorization for a given PPP
   user. The type of request is identified through the Request-Type AVP,
   and the default mode is both authentication and authorization.

   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 only
   SHOULD include the information from which the authorization will be
   performed, such as the User-Name, or DNIS and ANI AVPs. Certain
   networks MAY use different AVPs for authorization purposes. A request
   for authorization will include some AVPs defined in sections 2.0, 6.0
   and 7.0.

   It is possible for a single session to be authorized only first, then
   followed by an authentication request. However, the inverse SHOULD
   NOT be permitted.

   If the AA-Request is a result of an AA-Challenge-Ind, the Session-Id
   MUST be identical as the one provided in the initial AA-Request for
   the same session. If the AA-Request is a result of an AA-Challenge-
   Ind that included a State AVP, the same AVP MUST be present in the
   following AA-Request.


   Message Format















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      <AA-Request> ::= < Diameter Header: 265, R >
                       < Session-Id >
                       { Auth-Extension-Id }
                       { Origin-FQDN }
                       { Origin-Realm }
                       { Destination-Realm }
                       { Service-Type }
                       [ Destination-FQDN ]
                       [ NAS-Identifier ]
                       [ User-Name ]
                       [ User-Password ]
                       [ ARAP-Password ]
                       [ CHAP-Password ]
                       [ CHAP-Challenge ]
                       [ Idle-Timeout ]
                       [ State ]
                       [ Authorization-Lifetime ]
                       [ Session-Timeout ]
                     * [ AVP ]
                     * [ Proxy-Info ]
                     * [ Route-Record ]


3.1.1.1  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 following an AA-Challenge-Ind.

   This AVP MUST be encrypted using one of the methods described in [2]
   or [13]. Unless this AVP is used for one-time passwords, the User-
   Password AVP SHOULD NOT be used in non-trusted proxy environments.

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


3.1.1.2  CHAP-Password AVP

   The CHAP-Password AVP (AVP Code 3) is of type Complex and contains
   the response value provided by a PPP Challenge-Handshake
   Authentication Protocol (CHAP) [6] user in response to the challenge.

   If the CHAP-Password AVP is found in a message, the CHAP-Challenge
   AVP (see section 3.1.1.3) MUST be present as well.






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      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                         AVP Header (AVP Code = 3)
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  CHAP Ident   |    Data ...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The CHAP Ident field contains the one octet CHAP Identifier from the
   user's CHAP response [6]. The Data field is 16 octets, and contains
   the CHAP Response from the user. The actual computation of the CHAP
   response can be found in [6].


3.1.1.3  CHAP-Challenge AVP

   The CHAP-Challenge AVP (AVP Code 60) is of type OctetString and
   contains the CHAP Challenge sent by the NAS to a PPP Challenge-
   Handshake Authentication Protocol (CHAP) [6] user.


3.1.1.4  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 7.2.1) is
   included in the message and is set to ARAP. This AVP MUST NOT be
   present if the User-Password or CHAP-Password AVPs are present. See
   [32] for more information on the contents of this AVP.


3.1.2  AA-Answer (AAA) Command

   The AA-Answer (AAA) message, indicated by the Command-Code field set
   to 265 and the 'A' bit set in the message flags field, is sent in
   response to the AA-Request message. If authorization was requested, a
   successful response will include the authorization AVPs appropriate
   for the service being provided, as defined in section 2.0, 6.0 and
   7.0

   Message Format











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      <AA-Answer> ::= < Diameter Header: 265, A >
                      < Session-Id >
                      { Auth-Extension-Id }
                      { Result-Code }
                      { Origin-FQDN }
                      { Origin-Realm }
                      { Service-Type }
                      { Destination-FQDN }
                      [ User-Name ]
                      [ Error-Reporting-FQDN ]
                      [ Idle-Timeout ]
                      [ Authorization-Lifetime ]
                      [ Session-Timeout ]
                    * [ AVP ]
                    * [ Proxy-Info ]
                    * [ Route-Record ]


3.1.2.1  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 7.2.1)
   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 as
   the key. If the user's password is less than 8 octets in length, the
   password is padded at the end with NULL octets to a length of 8
   before using it as a key.


3.1.2.2  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 may be permitted before being
   disconnected. This AVP is primarily intended for use when the
   Framed-Protocol AVP (see Section 7.2.1) is set to ARAP.


3.1.3  AA-Challenge-Ind (ACI) Command

   The AA-Challenge-Ind (ACI) message, indicated by the Command-Code
   field set to 267 and the 'I' bit set in the message flags field, is
   sent by a Diameter Home server to issue a challenge requiring a
   response to a dial-up user. The message MAY have one or more Reply-



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   Message AVP, the User-Name AVP and it MAY have zero or one State AVP.
   No other AVPs are permitted in an AA-Challenge-Ind other than
   security related AVPs [2, 13].

   A Failed ACI would contain the same Command-Code, but would require
   that only be 'F' bit be set.

   On receipt of an AA-Challenge-Ind, the Identifier field is matched
   with a pending AA-Request. Invalid messages are silently discarded.

   The receipt of a valid AA-Challenge-Ind indicates that a new AA-
   Request SHOULD be sent. The NAS MAY display the text message, if any,
   to the user, and then prompt the user for a response.  It then sends
   its original AA-Request with a new request ID, with the User-Password
   AVP replaced by the user's response (encrypted), and including the
   State AVP from the AA-Challenge-Ind, if any.

   A NAS that supports PAP MAY forward the Reply-Message to the dial-in
   client and accept a PAP response which it can use as though the user
   had entered the response.  If the NAS cannot do so, it should treat
   the AA-Challenge-Ind as though it had received an AA-Answer with a
   Result-Code AVP set to a value other than DIAMETER_SUCCESS instead.

   When possible, authentication mechanisms that include more than a
   single authentication round trip SHOULD use EAP (see section 4.0)
   instead of the AA-Challenge-Ind. This command has been maintained for
   RADIUS backward compatibility.

      AA-Challenge-Ind ::= < Diameter Header: 267, I >
                           < Session-Id >
                           { Auth-Extension-Id }
                           { Result-Code }
                           { Destination-Realm }
                           { Destination-FQDN }
                           { Origin-FQDN }
                           { Origin-Realm }
                           { Service-Type }
                           [ User-Name ]
                           [ Error-Reporting-FQDN ]
                           [ State ]
                         * [ AVP ]
                         * [ Reply-Message ]
                         * [ Proxy-Info ]
                         * [ Route-Record ]


3.1.3.1  Prompt AVP




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   The Prompt AVP (AVP Code 76) is of type Unsigned32, and MAY be
   present in the AA-Challenge-Ind 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 [34].


3.2  Reply-Message AVP

   The Reply-Message AVP (AVP Code 18) is of type OctetString, encoded
   in the UTF-8 [29] format, and contains text which MAY be displayed to
   the user.  When used in an AA-Answer message with a successful
   Result-Code AVP it indicates the success message. When found in the
   same message with a Result-Code other than Diameter-SUCCESS it
   contains the failure message.

   The Reply-Message AVP MAY indicate a dialog message to prompt the
   user before another AA-Request attempt. When used in an AA-
   Challenge-Ind, it MAY indicate a dialog message to prompt the user
   for a response.

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


4.0  Extensible Authentication Protocol Support

   The Extensible Authentication Protocol (EAP), described in [25],
   provides a standard mechanism for support of additional
   authentication methods within PPP. Through the use of EAP, support
   for a number of authentication schemes may be added, including smart
   and token cards, Kerberos, Public Key, One Time Passwords, and
   others.

   This section describes the Command-Codes values and AVPs that are
   required for an EAP payload to be encapsulated within the Diameter
   protocol. Since authentication occurs between the PPP client and its
   home Diameter server, end-to-end authentication is achieved, reducing
   the possibility for fraudulent authentication, such as replay and
   man-in-the-middle attacks. End-to-end authentication also provides
   for mutual (bi-directional) authentication, which is not possible
   with PAP and CHAP in a roaming environment.

   The Diameter/EAP extension allows a home Diameter server to initiate
   an unsolicited authentication request to the user. This allows the
   home server to periodically ensure that the user is still active,



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   which is useful when a server requires re-authentication to extend
   the "life" of a session [26]. Server-initiated authentication can
   reduce the number of protocol exchanges over the Internet.

   The EAP conversation between the authenticating peer and the NAS
   begins with the negotiation of EAP within LCP. Once EAP has been
   negotiated, the NAS will typically send to the Diameter server a
   Diameter-EAP-Request message with a NULL EAP-Payload AVP, signifying
   an EAP-Start. The Port number and NAS Identifier MUST be included in
   the AVPs issued by the NAS in the Diameter-EAP-Request packet.

   If the Diameter home server supports EAP, it MUST respond with a
   Diameter-EAP-Ind message containing an EAP-Payload AVP that includes
   an encapsulated EAP payload [25]. The EAP payload is forwarded by the
   NAS to the PPP client. The initial Diameter-EAP-Ind normally includes
   an EAP-Request/Identity, requesting the PPP client to identify
   itself. Upon receipt of the PPP client's EAP-Response [25], the NAS
   will then issue a second Diameter-EAP-Request message, with the
   client's EAP payload encapsulated within the EAP-Payload AVP. The
   conversation continues until the Diameter server sends a Diameter-
   EAP-Answer with a Result-Code AVP indicating success or failure. A
   Result-Code AVP containing a failure indication SHOULD also include
   an EAP-Payload AVP containing an EAP-Failure [25] payload, and the
   NAS SHOULD disconnect the PPP client by issuing a LCP terminate. If
   the Result-Code AVP indicates success, the EAP-Payload AVP MUST
   encapsulate an EAP-Success [25] payload, and the NAS SHOULD
   successfully terminate the PPP authentication phase. If authorization
   was requested, a successful Diameter-EAP-Answer MUST also include the
   appropriate authorization AVPs required for the service requested
   (see sections 2.0, 6.0 and 7.0).

   The above scenario creates a situation in which the NAS never needs
   to manipulate an EAP packet. An alternative may be used in situations
   where an EAP-Request/Identity message will always be sent by the NAS
   to the authenticating peer. This involves having the NAS send an
   EAP-Request/Identity message to the PPP client, and forwarding the
   EAP-Response/Identity packet to the Diameter server in the EAP-
   Payload AVP of a Diameter-EAP-Request packet. While this approach
   will save a round-trip, it cannot be universally employed. There are
   circumstances in which the user's identity may not be needed (such as
   when authentication and accounting is handled based on the calling or
   called phone number), and therefore an EAP-Request/Identity packet
   may not necessarily be issued by the NAS to the authenticating peer.

   Unless the NAS interprets the EAP-Response/Identity packet returned
   by the authenticating peer, it will not have access to the user's
   identity. Therefore, the Diameter Server SHOULD return the user's
   identity by inserting it in the User-Name attribute of subsequent



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   Diameter-EAP-Answer packets. Without the user's identity, the
   Session-Id AVP MAY be used for accounting and billing, however
   operationally this MAY be very difficult to manage.

   The Diameter-EAP-Ind message MAY be sent by a Diameter server in
   order to initiate an unsolicited authentication of the PPP user, as
   described in [26]. This functionality allows a home Diameter server
   to easily extend the "life" of a session for a particular service,
   while reducing the total number of authentication round-trips, should
   the NAS initiate the periodic authentication.

   Should an EAP authentication session be interrupted due to a home
   server failure, the session MAY be directed to an alternate server,
   but the authentication session will have to be restarted from the
   beginning.

   When Diameter is used in a roaming environment, the NAS SHOULD issue
   the EAP-Request/Identity request to the PPP client, and forward the
   EAP-Response in the initial Diameter-EAP-Request message. This allows
   any Diameter proxies or brokers to identify the user, and forward the
   message to the appropriate home server. If a response is received
   with the Result-Code set to DIAMETER_COMMAND_UNSUPPORTED [2], it is
   an indication that a Diameter server in the proxy chain does not
   support EAP. The NAS MAY re-open LCP and attempt to negotiate another
   PPP authentication protocol, such as PAP or CHAP. A NAS SHOULD be
   cautious when determining whether a less secure authentication
   protocol will be used, since this could be a result of a bidding down
   attack.


4.1  Alternative uses

   Currently the conversation between the backend authentication server
   and the Diameter server is proprietary because of lack of
   standardization. In order to increase standardization and provide
   interoperability between Diameter vendors and backend security
   vendors, it is recommended that Diameter-encapsulated EAP be used for
   this conversation.

   This has the advantage of allowing the Diameter server to support EAP
   without the need for authentication-specific code within the Diameter
   server. Authentication-specific code can then reside on a backend
   authentication server instead.

   In the case where Diameter-encapsulated EAP is used in a conversation
   between a Diameter server and a backend authentication server, the
   latter will typically return an Diameter-EAP-Answer/EAP-Payload/EAP-
   Success message without inclusion of the expected authorization AVPs



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   required in a successful response. This means that the Diameter
   server MUST add these attributes prior to sending an Diameter-EAP-
   Answer/EAP-Payload/EAP-Success message to the NAS.


4.2  Command-Codes Values

   This section defines new Command-Code [2] values that MUST be
   supported by all Diameter implementations conforming to this
   specification. The following Command Codes are defined in this
   section:

      Command-Name             Abbrev.    Code       Reference
      --------------------------------------------------------
      Diameter-EAP-Answer       DEA       268          4.2.2
      Diameter-EAP-Ind          DEI       270          4.2.3
      Diameter-EAP-Request      DER       268          4.2.1



4.2.1  Diameter-EAP-Request (DER) Command

   The Diameter-EAP-Request (DER) command, indicated by the Command-Code
   field set to 268 and the 'R' bit set in the message flags field, is
   sent by a Diameter client to a Diameter server and conveys an EAP-
   Response [25] from the dial-up PPP client. The Diameter-EAP-Request
   MUST contain one EAP-Payload AVP, which contains the actual EAP
   payload. An EAP-Payload AVP with no data MAY be sent to the Diameter
   server to initiate an EAP authentication session.

   Upon receipt of a Diameter-EAP-Request, a Diameter server MUST issue
   a reply. The reply may be either:

      1) a Diameter-EAP-Ind containing an EAP-Request encapsulated
         within an EAP-Payload attribute
      2) a Diameter-EAP-Answer containing an EAP-Success encapsulated
         within an EAP-Payload and a Result-Code indicating success.
      3) a Diameter-EAP-Answer containing an EAP-Failure encapsulated
         within an EAP-Payload and a Result-Code indicating failure.
      4) A Message-Reject-Ind packet with a Result-Code set to
         DIAMETER_COMMAND_UNSUPPORTED if a Diameter server does not
         support the EAP extension.

   Message Format







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      <Diameter-EAP-Request> ::= < Diameter Header: 268, R >
                                 < Session-Id >
                                 { Auth-Extension-Id }
                                 { Origin-FQDN }
                                 { Origin-Realm }
                                 { Destination-Realm }
                                 { Service-Type }
                                 { EAP-Payload }
                                 [ Destination-FQDN ]
                                 [ Authorization-Lifetime ]
                                 [ Session-Timeout ]
                                 [ User-Name ]
                                 [ Idle-Timeout ]
                                 [ NAS-IP-Address ]
                                 [ NAS-Identifier ]
                                 [ State ]
                               * [ AVP ]
                               * [ Proxy-Info ]
                               * [ Route-Record ]


4.2.2  Diameter-EAP-Answer (DEA) Command

   The Diameter-EAP-Answer (DEA) message, indicated by the Command-Code
   field set to 268 and the 'A' bit set in the message flags field, is
   sent by the Diameter server to the client to indicate either a
   successful or failed authentication. The Diameter-EAP-Answer message
   SHOULD include an EAP payload of type EAP-Success or EAP-Failure
   encapsulated within an EAP-Payload AVP. The Result-Code AVP MUST
   indicate a failure if the EAP-Failure payload is present, while the
   AVP MUST indicate success if the EAP-Success payload is present.

   If the message from the Diameter client included a request for
   authorization, a successful response MUST include the authorization
   AVPs that are relevant to the service being provided.

   Message Format














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      <Diameter-EAP-Answer> ::= < Diameter Header: 268, A >
                                < Session-Id >
                                { Auth-Extension-Id }
                                { Result-Code }
                                { Origin-FQDN }
                                { Origin-Realm }
                                { Destination-FQDN }
                                { Service-Type }
                                [ Error-Reporting-FQDN ]
                                [ EAP-Payload ]
                                [ User-Name ]
                                [ Idle-Timeout ]
                                [ Authorization-Lifetime ]
                                [ Session-Timeout ]
                              * [ AVP ]
                              * [ Proxy-Info ]
                              * [ Route-Record ]


4.2.3  Diameter-EAP-Ind (DEI) Command

   The Diameter-EAP-Ind (DEI) command, indicated by the Command-Code set
   to 270 and the 'I' bit set in the message flags field, has two uses.
   This message MAY be sent in response to a Diameter-EAP-Request
   message, and MUST contain an EAP-Response payload [25] encapsulated
   within an EAP-Payload AVP.

   A Failed DEI would contain the same Command-Code, but would require
   that only be 'F' bit be set.

   Alternatively, this message MAY also be sent unsolicited from a
   Diameter server to a client to request re-authentication of a PPP
   client. For re-authentication, it is recommended that the Identity
   request be skipped in order to reduce the number of authentication
   round trips. This is only possible when the user's identity is
   already known by the home Diameter server.

   Upon receipt of the message, the NAS MUST issue the EAP payload to
   the PPP Client, and SHOULD respond with a Diameter-EAP-Request
   containing the EAP-Response [25] packet.

   Message Format









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      <Diameter-EAP-Ind> ::= <Diameter Header: 270, I>
                              < Session-Id >
                              { Auth-Extension-Id }
                              { Destination-FQDN }
                              { Destination-Realm }
                              { Origin-FQDN }
                              { Origin-Realm }
                              { EAP-Payload }
                              { Service-Type }
                              [ User-Name ]
                            * [ AVP ]
                            * [ Proxy-Info ]
                            * [ Route-Record ]


4.3  EAP-Payload AVP

   The EAP-Payload AVP (AVP Code 402) is of type OctetString and is used
   to encapsulate the actual EAP payload [25] that is being exchanged
   between the dial-up PPP client and the home Diameter server.


5.0  Diameter Session Termination

   When a Network Access Server (NAS) receives an indication that a
   user's session is being disconnected (e.g. LCP Terminate is
   received), the NAS MUST issue a Session-Termination-Request (STR) [2]
   to its Diameter Server. This will ensure that any resources
   maintained on the servers is freed appropriately.

   Further, a NAS that receives a Session-Termination-Ind (STI) [2] MUST
   disconnect the PPP (or tunneling) session and respond with an STR
   message.


6.0  Call and Session Information

   This section contains the authorization AVPs that are needed to
   identify call and session information, and allows the server to set
   constraints on a session.


6.1  NAS-Port AVP

   The NAS-Port AVP (AVP Code 5) is of type Unsigned32 and contains the
   physical port number of the NAS which is authenticating the user, and
   is normally only present in an authentication and/or authorization
   request. Note that this is using "port" in its sense of a physical



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   connection on the NAS, not in the sense of a TCP or UDP port number.
   Either NAS-Port or NAS-Port-Type (AVP Code 61) or both SHOULD be
   present in the request, if the NAS differentiates among its ports.


6.2  Filter-Id AVP

   The Filter-Id AVP (AVP Code 11) is of type OctetString, encoded in
   the UTF-8 [29] format, and contains the name of the filter list for
   this user. Zero or more Filter-Id AVPs MAY be sent in an
   authorization response.

   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 since filter naming differs
   from one service provider to another.

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


6.3  Callback-Number AVP

   The Callback-Number AVP (AVP Code 19) is of type OctetString, encoded
   in the UTF-8 [29] format, 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 the range of allowed usage of this field is
   outside the scope of this specification.


6.4  Callback-Id AVP

   The Callback-Id AVP (AVP Code 20) is of type OctetString, encoded in
   the UTF-8 [29] format, 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 since it assumes that the Callback-
   Id is configured on the NAS. It is therefore preferable to use the
   Callback-Number AVP instead.


6.5  Idle-Timeout AVP




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   The Idle-Timeout AVP (AVP Code 28) is of type Unsigned32 and sets the
   maximum number of consecutive seconds of idle connection allowed to
   the user before termination of the session or prompt. It MAY be used
   in an authentication and/or authorization request (or challenge) as a
   hint to the server that an idle timeout is desired, but the server is
   not required to honor the hint in the corresponding response.


6.6  Called-Station-Id AVP

   The Called-Station-Id AVP (AVP Code 30) is of type OctetString,
   encoded in the UTF-8 [29] format, and allows the NAS to send in the
   request the phone number that the user called, using Dialed Number
   Identification (DNIS) or a similar technology. Note that this may be
   different from the phone number the call comes in on. It SHOULD only
   be present in authentication and/or authorization requests.

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


6.7  Calling-Station-Id AVP

   The Calling-Station-Id AVP (AVP Code 31) is of type OctetString,
   encoded in the UTF-8 [29] format, and allows the NAS to send in the
   request the phone number that the call came from, using Automatic
   Number Identification (ANI) or a similar technology. It SHOULD only
   be present in authentication and/or authorization requests.


   If the 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 ANI.

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


6.8  NAS-Port-Type AVP

   The NAS-Port-Type AVP (AVP Code 61) is of type Unsigned32 and
   contains the type of the physical port of the NAS which is



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   authenticating the user. It can be used instead of or in addition to
   the NAS-Port (5) AVP.  This AVP SHOULD only be used in authentication
   and/or authorization requests. This AVP MAY be combined with the
   NAS-Port AVP to assist in differentiating its ports.

   The supported values are defined in [34].


6.9  Port-Limit AVP

   The Port-Limit AVP (AVP Code 62) is of type Unsigned32 and sets the
   maximum number of ports to be provided to the user by the NAS.  It
   MAY be used in an authentication and/or authorization request as a
   hint to the server that multilink PPP [9] service is desired, but the
   server is not required to honor the hint in the corresponding
   response.


6.10  Connect-Info AVP

   The Connect-Info AVP (AVP Code 77) is of type OctetString and is sent
   in the AA-Request message, and indicates the nature of the user's
   connection. The value consists of UTF-8 encoded 10646 characters.
   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, they may both be included in the first AVP
   with the transmit speed first (the speed the NAS modem transmits at),
   a slash (/), the receive speed, then optionally other information.


7.0  Service Specific Authorization AVPs

   This section contains the RADIUS authorization AVPs that are
   supported in the Diameter protocol. The Service-Type AVP MUST be
   present in all messages, and based on the value of the Service-Type
   AVP, additional AVPs defined in sections 7.2, 7.3 and 7.4 MAY be
   present.


7.1  Service-Type AVP

   The Service-Type AVP (AVP Code 6) is of type Unsigned32 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, and MUST treat unknown or unsupported
   Service-Types as though a response with a Result-Code other than
   Diameter-SUCCESS had been received instead.



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   When used in a request, the Service-Type AVP SHOULD be considered to
   be a hint to the server that the NAS has reason to believe the user
   would prefer the kind of service indicated, but the server is not
   required to honor the hint. The following values have been defined
   for the Service-Type AVP:

   The complete list of defined values can be found in [1] and [34]. The
   following values are extracted from [1], and are listed here since
   they are further qualified:

      Login               1
         The user should be connected to a host. The message MAY include
         additional AVPs defined in section 7.3.

      Framed              2
         A Framed Protocol should be started for the User, such as PPP
         or SLIP. The message MAY include additional AVPs defined in
         section 7.2, or 7.4 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
         section 7.3.

      Callback Framed     4
         The user should be disconnected and called back, then a Framed
         Protocol should be started for the User, such as PPP or SLIP.
         The message MAY include additional AVPs defined in section 7.2,
         or 7.4 for tunneling services.


7.2  Framed Access Authorization AVPs

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


7.2.1  Framed-Protocol AVP

   The Framed-Protocol AVP (AVP Code 7) is of type Unsigned32 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 [34].


7.2.2  Framed-Routing AVP



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   The Framed-Routing AVP (AVP Code 10) is of type Unsigned32 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 [34].


7.2.3  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
   between the range of 64 and 65535.


7.2.4  Framed-Compression AVP

   The Framed-Compression AVP (AVP Code 13) is of type Unsigned32 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. It is the
   responsibility of the NAS to apply the proper compression protocol to
   appropriate link traffic.

   The supported values are listed in [34].


7.2.5  IP Access

   The AVPs defined in this section are used when the user requests, or
   is being granted, access to IP. They are only present if the Framed-
   Protocol AVP (see Section 7.2.1) is set to PPP, SLIP, Gandalf
   proprietarySingleLink/MultiLink protocol, or X.75 Synchronous.


7.2.5.1  Framed-IP-Address AVP

   The Framed-IP-Address AVP (AVP Code 8) is of type Address and
   contains the address 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



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   select an address (e.g. 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).


7.2.5.2  Framed-IP-Netmask AVP

   The Framed-IP-Netmask AVP (AVP Code 9) is of type Address and
   contains the IP 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 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.


7.2.5.3  Framed-IP-Route AVP

   The Framed-IP-Route AVP (AVP Code 22) is of type OctetString, encoded
   in the UTF-8 [29] format, and contains the routing information to be
   configured for the user on the NAS. Zero or more such 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. That 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, 16 bits for class B prefixes, and 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.


7.2.6  IPX Access

   The AVPs defined in this section are used when the user requests, or
   is being granted, access to IPX. They are only present if the
   Framed-Protocol AVP (see Section 7.2.1) is set to PPP, Xylogics
   proprietary IPX/SLIP, Gandalf proprietarySingleLink/MultiLink
   protocol, or X.75 Synchronous.


7.2.6.1  Framed-IPX-Network AVP



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   The Framed-IPX-Network AVP (AVP Code 23) is of type OctetString,
   encoded in the UTF-8 [29] format, 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 (e.g. Negotiated). The value 0xFFFFFFFE indicates
   that the NAS should select an address for the user (e.g. assigned
   from a pool of one or more IPX networks kept by the NAS).


7.2.7  Appletalk Access

   The AVPs defined in this section are used when the user requests, or
   is being granted, access to Appletalk. They are only present if the
   Framed-Protocol AVP (see Section 7.2.1) is set to PPP, Gandalf
   proprietary SingleLink/MultiLink protocol, or X.75 Synchronous.


7.2.7.1  Framed-AppleTalk-Link AVP

   The Framed-AppleTalk-Link AVP (AVP Code 37) is of type Unsigned32 and
   contains the AppleTalk network number which 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 zero to 65535. The
   special value of zero indicates that this is an unnumbered serial
   link.  A value of one to 65535 means that the serial line between the
   NAS and the user should be assigned that value as an AppleTalk
   network number.


7.2.7.2  Framed-AppleTalk-Network AVP

   The Framed-AppleTalk-Network AVP (AVP Code 38) is of type Unsigned32
   and contains the AppleTalk Network number which 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 zero to 65535. The
   special value zero indicates that the NAS should assign a network for



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   the user, using its default cable range. A value between one and
   65535 (inclusive) indicates the AppleTalk Network the NAS should
   probe to find an address for the user.


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


7.2.8  ARAP Access

   The AVPs defined in this section are used when the user requests, or
   is being granted, access to ARAP. They are only present if the
   Framed-Protocol AVP (see Section 7.2.1) is set to AppleTalk Remote
   Access Protocol (ARAP).


7.2.8.1  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 [32] for more information of the format of
   this AVP.


7.2.8.2  ARAP-Zone-Access AVP

   The ARAP-Zone-Access AVP (AVP Code 72) is of type Unsigned32, 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 [34], and are defined in [32].


7.2.8.3  ARAP-Security AVP

   The ARAP-Security AVP (AVP Code 73) is of type Unsigned32, and MAY be
   present in the AA-Challenge-Ind message if the Framed-Protocol AVP is
   set to the value of ARAP.  See [32] for more information of the
   format of this AVP.




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7.2.8.4  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-Challenge-Ind message if the
   Framed-Protocol AVP is set to the value of ARAP.  This AVP contains
   the security module challenge or response associated with the ARAP
   Security Module specified in ARAP-Security.


7.3  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".


7.3.1  Login-IP-Host AVP

   The Login-IP-Host AVP (AVP Code 14) is of type Address and contains
   the system with which to connect the user, when the Login-Service AVP
   is included. It MAY be used in an authorization request as a hint to
   the server that a specific host 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. The value zero indicates that the NAS SHOULD
   select a host to connect the user to.


7.3.2  Login-Service AVP

   The Login-Service AVP (AVP Code 15) is of type Unsigned32 and
   contains the service which 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 [34].


7.3.3  TCP Services

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


7.3.3.1  Login-TCP-Port AVP



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   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 65535.


7.3.4  LAT Services

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


7.3.4.1  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 the service attribute when dealing with clustered
   systems, such as a VAX or Alpha cluster. In such an environment
   several different time sharing hosts share the same resources (disks,
   printers, etc.), and administrators often configure each 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.
   Alternately, 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 lower case
   alphabetics, and the ISO Latin-1 character set extension [8]. All LAT
   string comparisons are case insensitive.


7.3.4.2  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



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   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
   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 lower case
   alphabetics, and the ISO Latin-1 character set extension [8]. All LAT
   string comparisons are case insensitive.


7.3.4.3  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 which 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 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 bit map. The administrators assign a
   bitmap of authorized group codes to each user; LAT gets these from
   the operating system, and uses these 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.


7.3.4.4  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 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 lower case



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   alphabetics, and the ISO Latin-1 character set extension [8]. All LAT
   string comparisons are case insensitive.


7.4  Tunneling AVP

   The Tunneling AVP (AVP Code 403) is of type Grouped and contains AVPs
   used to describe a tunnel. Its Data field has the following ABNF
   grammar:

      Tunneling   = Type Medium Cep Sep Pw Gid Aid Pref Caid Said
         Type        = Tunnel-Type ; See Section 7.4.1
         Medium      = Tunnel-Medium-Type ; See Section 7.4.2
         Cep         = Tunnel-Client-Endpoint ; See Section 7.4.3
         Sep         = Tunnel-Server-Endpoint ; See Section 7.4.4
         Pw          = Tunnel-Password ; See Section 7.4.5
         Gid         = Tunnel-Private-Group-ID ; See Section 7.4.6
         Aid         = Tunnel-Assignment-ID ; See Section 7.4.7
         Pref        = Tunnel-Preference ; See Section 7.4.8
         Caid        = Tunnel-Client-Auth-ID ; See Section 7.4.9
         Said        = Tunnel-Server-Auth-ID ; See Section 7.1.4.10

      +---------------------------------------------------------------+
      |                 AVP Header (AVP Code = 403)                   |
      +---------------------------------------------------------------+
      |                        Tunnel-Type AVP                        |
      +---------------------------------------------------------------+
      |                    Tunnel-Medium-Type AVP                     |
      +---------------------------------------------------------------+
      |                  Tunnel-Client-Endpoint AVP                   |
      +---------------------------------------------------------------+
      |                  Tunnel-Server-Endpoint AVP                   |
      +---------------------------------------------------------------+
      |                      Tunnel-Password AVP                      |
      +---------------------------------------------------------------+
      |                 Tunnel-Private-Group-Id AVP                   |
      +---------------------------------------------------------------+
      |                   Tunnel-Assignment-ID AVP                    |
      +---------------------------------------------------------------+
      |                     Tunnel-Preference AVP                     |
      +---------------------------------------------------------------+
      |                   Tunnel-Client-Auth-ID AVP                   |
      +---------------------------------------------------------------+
      |                   Tunnel-Server-Auth-ID AVP                   |
      +---------------------------------------------------------------+


7.4.1  Tunnel-Type AVP



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   The Tunnel-Type AVP (AVP Code 64) is of type Unsigned32 and contains
   the tunneling protocol(s) to be used (in the case of a tunnel
   initiator) or the the tunneling protocol 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 SHOULD also be present in the corresponding ADIF
   Record within the Accounting-Request.

   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 was received with the Result-Code indicating a
   failure.

   The supported values are listed in [34].


7.4.2  Tunnel-Medium-Type AVP

   The Tunnel-Medium-Type AVP (AVP Code 65) is of type Unsigned32 and
   contains the transport medium to use when creating a tunnel for those
   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 Value field contains one of the values listed under "Address
   Family Numbers" in [10]. The value of most importance is (1) for IPv4
   and (2) for IPv6.


7.4.3  Tunnel-Client-Endpoint AVP

   The Tunnel-Client-Endpoint AVP (AVP Code 66) is of type OctetString,
   encoded in the UTF-8 [29] format, 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 ADIF Record of 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 [2], MAY be used to provide
   a globally unique means to identify a tunnel for accounting and



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   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
   it is a "dotted-decimal" IP address.  Conformant 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 it is a text representation of
   the address in either the preferred or alternate form [5].
   Conformant 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, this string is a tag
   referring to configuration data local to the Diameter client that
   describes the interface and medium-specific address to use.


7.4.4  Tunnel-Server-Endpoint AVP

   The Tunnel-Server-Endpoint AVP (AVP Code 67) is of OctetString,
   encoded in the UTF-8 [29] format, 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 ADIF Record of 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 [2], 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
   it is a "dotted-decimal" IP address.  Conformant 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 it is a text representation of
   the address in either the preferred or alternate form [5].
   Conformant implementations MUST support the preferred form and SHOULD
   support both the alternate text form and the FQDN format for IPv6
   addresses.



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   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 and medium-specific address to use.


7.4.5  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.
   This AVP MUST only be present in authorization responses in an
   encrypted form, using one of the methods described in [2] and [13].


7.4.6  Tunnel-Private-Group-ID AVP

   The Tunnel-Private-Group-ID AVP (AVP Code 81) is of type OctetString,
   encoded in the UTF-8 [29] format, 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
   pre-determine the group resulting from a particular connection and
   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 value SHOULD be included the corresponding ADIF-Record in the
   Accounting-Request which pertain to a tunneled session.


7.4.7  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 utilize its own dedicated tunnel. This attribute provides
   a mechanism for Diameter to be used 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



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   indicate that a particular session is to be assigned to a tunnel that
   provides an appropriate level of service.  It is expected that any
   QOS-related Diameter tunneling attributes defined in the future that
   accompany this attribute 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 intended to be of only
   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 assign
   the session to an arbitrary multiplexed or non-multiplexed tunnel
   between the desired endpoints.  This attribute SHOULD also be
   included in the corresponding ADIF-Record in the Accounting-Request
   messages which pertain to a 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
        and subsequent sessions 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 such
   tunnels are between different endpoints.


7.4.8  Tunnel-Preference AVP

   The Tunnel-Preference AVP (AVP Code 83) is of type Unsigned32 and is



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   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
   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 having the numerically lowest 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.


7.4.9  Tunnel-Client-Auth-ID AVP

   The Tunnel-Client-Auth-ID AVP (AVP Code 90) is of type Unsigned32 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 corresponding
   ADIF-Record of the Accounting-Request messages which pertain to a
   tunneled session.


7.4.10  Tunnel-Server-Auth-ID AVP

   The Tunnel-Server-Auth-ID AVP (AVP Code 91) is of type OctetString
   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 corresponding
   ADIF-Record of the Accounting-Request messages which pertain to a
   tunneled session.




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8.0  Accounting AVPs

   This section contains a description of the AVPs defined in this
   document that are to be included in Diameter accounting messages [2].


8.1  Accounting-Input-Octets AVP

   The Accounting-Input-Octets AVP (AVP Code 42) is of type Unsigned64,
   and contains the number of octets in IP packets received by the user.


8.2  Accounting-Output-Octets AVP

   The Accounting-Output-Octets AVP (AVP Code 43) is of type Unsigned64,
   and contains the number of octets in IP packets sent to the user.


8.3  Accounting-Session-Time AVP

   The Accounting-Session-Time AVP (AVP Code 46) is of type Unsigned32,
   and indicates the length of the current session in seconds.


8.4  Accounting-Input-Packets AVP

   The Accounting-Input-Packets (AVP Code 47) is of type Unsigned64, and
   contains the number of IP packets received by the user.


8.5  Accounting-Output-Packets AVP

   The Accounting-Output-Packets (AVP Code 48) is of type Unsigned64,
   and contains the number of IP packets sent to the user.


8.6  Accounting-Authentication-Type AVP

   The Accounting-Authentication-Type AVP (AVP Code 45) is of type
   Unsigned32, and specifies how the user was authenticated. The
   supported values are listed in [34].


8.7  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



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   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 fully identify an L2TP tunnel
   connection, the L2TP Tunnel ID and Call ID might be encoded in this
   field. The exact encoding of this field is implementation dependent.


8.8  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.


9.0  Interactions with Resource Management

   The Resource Management extension [31] provides the ability for a
   Diameter node to query a peer for session state information. The
   document states that service-specific extensions are responsible for
   specifying what AVPs are to be present in the Resource-Token [31]
   AVP.

   In addition to the AVPs listed in [31], the Resource-Token with the
   Extension-Id AVP set to one (1) MUST include the Service-Type AVP. In
   the event of a framed (PPP) user, the Framed-IP-Address and Framed-
   IPX-Network MUST be present if the corresponding network is being
   used. For Login users, the Login-IP-Host AVP and Login-Service AVP
   MUST be present. For tunneling users, the Tunnel-Type, Tunnel-
   Medium-Type, Tunnel-Client-Endpoint, and the Tunnel-Server-Endpoint
   AVPs MUST be present.


10.0  RADIUS/Diameter Protocol Interactions

   This section describes some basic guidelines that may be used by
   servers that act as protocol gateways. Note that this document does
   not restrict implementations from creating other methods, as long as
   the bridging function doesn't break the RADIUS nor the Diameter
   protocol.

   There are essentially two different situations that must be handled;
   one where a RADIUS request is received that must be forwarded as a
   Diameter request, and the inverse. Note that this section uses two
   different terms; AVP and attribute. The former is used to signify a
   Diameter AVP, while the latter is used to signify a RADIUS attribute.





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10.1  RADIUS request forwarded as Diameter request

   This section describes the actions that should be followed when a
   protocol Gateway receives a RADIUS message that is to be translated
   to a Diameter message.

   It is important to note that RADIUS servers are inherently stateless,
   and this section maintains that assumption. It is quite possible for
   the RADIUS messages that comprises the session (i.e. authentication
   and accounting messages) be handled by different protocol gateways in
   the proxy network.  Therefore a RADIUS->Diameter protocol gateway
   cannot maintain session state information.

   When a protocol gateway receives a RADIUS message, the following
   steps should be taken:

      - If the NAS-IP-Address attribute is present in the RADIUS
        message, the name MUST be translated to its corresponding FQDN,
        and encoded in the Diameter message's Origin-FQDN AVP. If the
        NAS-Identifier attribute is present, the data can be used in the
        Origin-FQDN AVP.
      - The Origin-FQDN AVP is added with the local server's identity.
        This will ensure that the corresponding response will be
        returned to the correct gateway server.
      - The Destination-Realm AVP is created from the information found
        in the RADIUS User-Name attribute.
      - The Gateway Server must maintain state information relevant to
        the RADIUS request, such as the Identifier field in the RADIUS
        header, any existing RADIUS Proxy-State attribute as well as the
        source IP address and port number of the UDP packet. These may
        be maintained locally in a state table, or may be saved in a
        Proxy-Info AVP.
      - If the Acct-Session-Id attribute was found in the request, the
        contents are inserted in the Acct-Session-Id AVP.
      - If the RADIUS request contained a Class or State attribute, and
        the prefix of the data is "Diameter/", the data following the
        prefix contains the Diameter 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.
      - If the RADIUS message received is an Accounting-Request, with
        the Acct-Status-Type attribute set to STOP, the local server
        MUST issue a Session-Termination-Request message once the
        Diameter Accounting-Answer has been received.

   The corresponding Diameter response is always guaranteed to be
   received by the same protocol gateway that translated the original
   request, due to the contents of the Origin-FQDN AVP in the Diameter



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   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-Challenge, the
        Diameter Session-Id and the Origin-FQDN AVPs are saved in the
        RADIUS State attribute, with the prefix "Diameter/". This is
        necessary in order to ensure that the protocol gateway that will
        receive the subsequent RADIUS Access-Request will have access to
        the Session Identifier, and be able to set the Destination-FQDN
        to the correct value.
      - 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 protocol
        gateway, 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, or in a local state table.
      - If state information regarding the RADIUS request was saved in a
        Proxy-Info AVP, the RADIUS Identifier and UDP IP Address and
        port number are extracted and used in issuing the RADIUS reply.


10.2  Diameter request forwarded as RADIUS request

   When a server receives a Diameter request that is to be forwarded to
   a RADIUS entity, the following steps are an example of the steps that
   may be followed:

      - The Origin-FQDN AVP's value is inserted in 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 it MAY be encoded in a RADIUS Proxy-State
        attribute:
           1. Origin-FQDN AVP
           2. Session-Id AVP
           3. Proxy-Info AVP
           4. Route-Record AVPs (in the proper order)
           5. Any other AVP that MUST be present in the response, and
              has no corresponding RADIUS attribute.

   When the corresponding response is received by the gateway server,
   which is guaranteed in the RADIUS protocol, the following steps may
   be followed:




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      - If a Proxy-Info AVP is present, extract the encoded information,
        otherwise retrieve the information from the local state table.
      - The request's Origin-FQDN information is added to the
        Destination-FQDN AVP.
      - The Session-Id information is added to the Session-Id AVP.
      - The Route-Record AVPs MUST be added to the Diameter message, in
        the same order they were present in the request.
     - If a Proxy-Info AVP was present in the request, the same AVP MUST
        be added to the response.
      - If the RADIUS Class or State attributes are present, these
        attributes must be present in the Diameter response.
      - Any other AVPs that were saved, and MUST be present in the
        response, are added to the message.


11.0  AVP Occurrence Table

   The following tables presents the AVPs defined in this document, and
   specifies in which Diameter messages they MAY, or MAY NOT be present.
   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.


11.1  NASREQ Command AVP Table

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

                                 +-----------------------------------+
                                 |            Command-Code           |
                                 |-----+-----+-----+-----+-----+-----+
   Attribute Name                | AAR | AAA | ACI | DER | DEA | DEI |
   ------------------------------|-----+-----+-----+-----+-----|-----|
   ARAP-Challenge-Response       | 0   | 0-1 | 0-1 | 0   | 0-1 | 0-1 |
   ARAP-Features                 | 0   | 0-1 | 0-1 | 0   | 0-1 | 0-1 |
   ARAP-Password                 | 0-1 | 0   | 0   | 0-1 | 0   | 0   |
   ARAP-Security                 | 0-1 | 0   | 0-1 | 0-1 | 0   | 0-1 |
   ARAP-Security-Data            | 0+  | 0   | 0   | 0+  | 0   | 0   |
   ARAP-Zone-Access              | 0   | 0-1 | 0   | 0   | 0-1 | 0   |
   Callback-Id                   | 0   | 0-1 | 0   | 0   | 0-1 | 0   |



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                                 +-----------------------------------+
                                 |            Command-Code           |
                                 |-----+-----+-----+-----+-----+-----+
   Attribute Name                | AAR | AAA | ACI | DER | DEA | DEI |
   ------------------------------|-----+-----+-----+-----+-----|-----|
   Auth-Extension-Id             | 1   | 1   | 1   | 1   | 1   | 1   |
   Authorization-Lifetime        | 0-1 | 0-1 | 0   | 0-1 | 0-1 | 0   |
   Callback-Number               | 0-1 | 0-1 | 0   | 0-1 | 0-1 | 0   |
   Called-Station-Id             | 0-1 | 0   | 0   | 0-1 | 0   | 0   |
   Calling-Station-Id            | 0-1 | 0   | 0   | 0-1 | 0   | 0   |
   CHAP-Challenge                | 0-1 | 0   | 0   | 0   | 0   | 0   |
   CHAP-Password                 | 0-1 | 0   | 0   | 0   | 0   | 0   |
   Class                         | 0   | 0+  | 0   | 0   | 0+  | 0   |
   Connect-Info                  | 0-1 | 0   | 0   | 0-1 | 0   | 0   |
   Destination-FQDN              | 0+  | 1   | 1   | 0+  | 1   | 1   |
   Destination-Realm             | 0   | 1   | 1   | 1   | 0   | 1   |
   EAP-Payload                   | 0   | 0   | 0   | 1   | 1   | 1   |
   Error-Reporting-FQDN          | 0   | 0+  | 0+  | 0   | 0+  | 0   |
   Filter-Id                     | 0   | 0+  | 0   | 0   | 0+  | 0   |
   Filter-Rule                   | 0   | 0+  | 0   | 0   | 0+  | 0   |
   Framed-Appletalk-Link         | 0   | 0-1 | 0   | 0   | 0-1 | 0   |
   Framed-Appletalk-Network      | 0   | 0+  | 0   | 0   | 0+  | 0   |
   Framed-Appletalk-Zone         | 0   | 0-1 | 0   | 0   | 0-1 | 0   |
   Framed-Compression            | 0+  | 0+  | 0   | 0+  | 0+  | 0   |
   Framed-IP-Address             | 0-1 | 0   | 0   | 0-1 | 0   | 0   |
   Framed-IP-Netmask             | 0-1 | 0-1 | 0   | 0-1 | 0-1 | 0   |
   Framed-IP-Route               | 0   | 0+  | 0   | 0   | 0+  | 0   |
   Framed-IPX-Network            | 0   | 0-1 | 0   | 0   | 0-1 | 0   |
   Framed-MTU                    | 0   | 0-1 | 0   | 0   | 0-1 | 0   |
   Framed-Protocol               | 0-1 | 0   | 0   | 0-1 | 0   | 0   |
   Framed-Routing                | 0-1 | 0   | 0   | 0-1 | 0   | 0   |
   Idle-Timeout                  | 0-1 | 0-1 | 0   | 0-1 | 0-1 | 0   |
   Login-IP-Host                 | 0+  | 0+  | 0   | 0   | 0   | 0   |
   Login-LAT-Group               | 0-1 | 0-1 | 0   | 0   | 0   | 0   |
   Login-LAT-Node                | 0-1 | 0-1 | 0   | 0   | 0   | 0   |
   Login-LAT-Port                | 0-1 | 0-1 | 0   | 0   | 0   | 0   |
   Login-LAT-Service             | 0-1 | 0-1 | 0   | 0   | 0   | 0   |
   Login-Service                 | 0   | 0+  | 0   | 0   | 0   | 0   |
   Login-TCP-Port                | 0   | 0+  | 0   | 0   | 0   | 0   |
   NAS-IP-Address                | 1   | 0   | 0   | 1   | 0   | 0   |
   NAS-Port                      | 1   | 0   | 0   | 1   | 0   | 0   |
   NAS-Port-Type                 | 0-1 | 0   | 0   | 0-1 | 0   | 0   |
   Origin-FQDN                   | 1   | 1   | 1   | 1   | 1   | 1   |
   Origin-Realm                  | 1   | 1   | 1   | 1   | 1   | 1   |
   Password-Retry                | 0   | 0-1 | 0   | 0   | 0   | 0   |
   Port-Limit                    | 0-1 | 0   | 0   | 0-1 | 0   | 0   |
   Prompt                        | 0   | 0   | 0-1 | 0   | 0   | 0   |
   Proxy-Info                    | 0+  | 0+  | 0+  | 0+  | 0+  | 0+  |



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   Reply-Message                 | 0   | 0   | 0+  | 0   | 0   | 0   |
                                 +-----------------------------------+
                                 |            Command-Code           |
                                 |-----+-----+-----+-----+-----+-----+
   Attribute Name                | AAR | AAA | ACI | DER | DEA | DEI |
   ------------------------------|-----+-----+-----+-----+-----|-----|
   Request-Type                  | 1   | 1   | 0   | 1   | 1   | 0   |
   Result-Code                   | 0   | 1   | 0   | 0   | 1   | 0   |
   Route-Record                  | 0+  | 0+  | 0+  | 0+  | 0+  | 0+  |
   Service-Type                  | 1   | 1   | 0   | 1   | 1   | 0   |
   Session-Id                    | 1   | 1   | 1   | 1   | 1   | 1   |
   Session-Timeout               | 0   | 0-1 | 0   | 0   | 0-1 | 0   |
   State                         | 0-1 | 0-1 | 0-1 | 0   | 0-1 | 0   |
   Tunneling                     | 0+  | 0+  | 0   | 0+  | 0+  | 0   |
   User-Name                     | 0-1 | 0-1 | 0-1 | 0-1 | 0-1 | 0-1 |
   User-Password                 | 0-1 | 0   | 0   | 0   | 0   | 0   |


11.2  Accounting AVP Table

   The tables in this section are used to represent which AVPs defined
   in this document are to be present in the Accounting messages,
   defined in [1].


   11.2.1  Framed Access

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






















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                                 +-----------------------+
                                 |      Command-Code     |
                                 |-----+-----+-----+-----+
   Attribute Name                | ACR | ACA | ASI | API |
   ------------------------------|-----+-----+-----+-----+
   Accounting-Authentication-Type| 1   | 0-1 | 0   | 0   |
   Accounting-Input-Octets       | 1   | 1   | 0   | 0   |
   Accounting-Input-Packets      | 1   | 1   | 0   | 0   |
   Accounting-Output-Octets      | 1   | 1   | 0   | 0   |
   Accounting-Output-Packets     | 1   | 1   | 0   | 0   |
   Accounting-Session-Time       | 1   | 1   | 0   | 0   |
   Accounting-State              | 0   | 0   | 1   | 0   |
   Acct-Tunnel-Connection        | 0-1 | 0-1 | 0   | 0   |
   Acct-Tunnel-Packets-Lost      | 0-1 | 0-1 | 0   | 0   |
   Framed-AppleTalk-Link         | 0-1 | 0-1 | 0   | 0   |
   Framed-AppleTalk-Network      | 0-1 | 0-1 | 0   | 0   |
   Framed-AppleTalk-Zone         | 0-1 | 0-1 | 0   | 0   |
   Framed-Compression            | 0-1 | 0-1 | 0   | 0   |
   Framed-IP-Address             | 0-1 | 0-1 | 0   | 0   |
                                 +-----------------------+
                                 |      Command-Code     |
                                 |-----+-----+-----+-----+
   Attribute Name                | ACR | ACA | ASI | API |
   ------------------------------|-----+-----+-----+-----+
   Framed-IP-Netmask             | 0-1 | 0-1 | 0   | 0   |
   Framed-IPX-Network            | 0-1 | 0-1 | 0   | 0   |
   Framed-MTU                    | 0-1 | 0-1 | 0   | 0   |
   Framed-Protocol               | 0-1 | 0-1 | 0   | 0   |
   Framed-Route                  | 0-1 | 0-1 | 0   | 0   |
   Framed-Routing                | 0-1 | 0-1 | 0   | 0   |
   Service-Type                  | 1   | 1   | 0   | 0   |
   Tunnel-Assignment-ID          | 0-1 | 0-1 | 0   | 0   |
   Tunnel-Client-Endpoint        | 0-1 | 0-1 | 0   | 0   |
   Tunnel-Medium-Type            | 0-1 | 0-1 | 0   | 0   |
   Tunnel-Private-Group-ID       | 0-1 | 0-1 | 0   | 0   |
   Tunnel-Server-Endpoint        | 0-1 | 0-1 | 0   | 0   |
   Tunnel-Type                   | 0-1 | 0-1 | 0   | 0   |
   ------------------------------|-----+-----+-----+-----+


   11.2.2  Non-Framed Access

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







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                                 +-----------------------+
                                 |      Command-Code     |
                                 |-----+-----+-----+-----+
   Attribute Name                | ACR | ACA | ASI | API |
   ------------------------------|-----+-----+-----+-----+
   Accounting-Authentication-Type| 1   | 0-1 | 0   | 0   |
   Accounting-Input-Octets       | 1   | 1   | 0   | 0   |
   Accounting-Input-Packets      | 1   | 1   | 0   | 0   |
   Accounting-Output-Octets      | 1   | 1   | 0   | 0   |
   Accounting-Output-Packets     | 1   | 1   | 0   | 0   |
   Accounting-Session-Time       | 1   | 1   | 0   | 0   |
   Accounting-State              | 0   | 0   | 1   | 0   |
   Login-IP-Host                 | 0-1 | 0-1 | 0   | 0   |
   Login-LAT-Service             | 0-1 | 0-1 | 0   | 0   |
   Login-LAT-Node                | 0-1 | 0-1 | 0   | 0   |
   Login-LAT-Group               | 0-1 | 0-1 | 0   | 0   |
   Login-LAT-Port                | 0-1 | 0-1 | 0   | 0   |
   Login-Service                 | 0-1 | 0-1 | 0   | 0   |
   Login-TCP-Port                | 0-1 | 0-1 | 0   | 0   |
   Service-Type                  | 1   | 1   | 0   | 0   |
   ------------------------------|-----+-----+-----+-----+


12.0  IANA Considerations

   This section contains the namespaces that have either been created in
   this specification, or the values assigned to existing namespaces
   managed by IANA.


12.1  Command Codes

   This specification assigns the values 265, 267, 268 and 270 from the
   Command Code namespace defined in [2], and extended in [13] and [30].
   See sections 3.1 and 4.2 for the assignment of the namespace in this
   specification.


12.2  AVP Codes

   This specification assigns the values 400-403 from the AVP Code
   namespace defined in [2], and extended in [13] and [30]. See section
   2.1 for the assignment of the namespace in this specification.

   This specification also makes use of AVPs in the 0-255 range, which
   are defined in [34].





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12.3  Request-Type AVP Values

   As defined in Section 2.1.1, the Request-Type AVP (AVP Code 401)
   defines the values 1-3. All remaining values are available for
   assignment via IETF Consensus [27].


12.4  Extension Identifier

   This specification assigns the value one (1) to the Extension
   Identifier namespace defined in [1]. See section 1.2 for more
   information.


13.0  Security Considerations

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

   The use of PAP SHOULD be discouraged, since it exposes user's
   passwords to possibly non-trusted entities. PAP is also frequently
   used for use with One-Time Passwords (OTP), which does not expose any
   security risks. However, it is highly recommended that OTP be
   supported through the EAP protocol.

   This document also describes how CHAP can be carried within the
   Diameter protocol, which is required for backward RADIUS
   compatibility. The CHAP protocol, as used in a RADIUS environment,
   facilitates authentication replay attacks, and therefore SHOULD NOT
   be used when EAP is available.


14.0  References


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

   [2]  Calhoun, Rubens, Akhtar, Guttman, "Diameter Base Protocol",
        draft-ietf-aaa-diameter-04.txt, IETF work in progress, May 2001.

   [3]  Aboba, Beadles, "The Network Access Identifier." RFC 2486. Janu-
        ary 1999.

   [4]  Aboba, Zorn, "Criteria for Evaluating Roaming Protocols", RFC
        2477, January 1999.



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   [5]  Hinden, R., Deering, S., "IP Version 6 Addressing Architecture",
        RFC 2373, July 1998

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

   [7]  Jacobson, "Compressing TCP/IP headers for low-speed serial
        links", RFC 1144, February 1990.

   [8]  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>

   [9]  Sklower, Lloyd, McGregor, Carr, "The PPP Multilink Protocol
        (MP)", RFC 1717, November 1994.

   [10] Reynolds, J., Postel, J., "Assigned Numbers", STD 2, RFC 1700,
        October 1994

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

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

   [13] P. Calhoun, W. Bulley, S. Farrell, "Diameter End-to-End Security
        Extension", draft-ietf-aaa-diameter-e2e-sec-02.txt, IETF work in
        progress, May 2001.

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

   [15] Valencia, A., Littlewood, M., Kolar, T., "Cisco Layer Two For-
        warding (Protocol) 'L2F'", RFC 2341, May 1998

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

   [17] Hamzeh, K., "Ascend Tunnel Management Protocol - ATMP", RFC
        2107, February 1997

   [18] Kent, S., Atkinson, R., "Security Architecture for the Internet
        Protocol", RFC 2401, November 1998

   [19] Perkins, C., "IP Encapsulation within IP", RFC 2003, October



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        1996

   [20] Perkins, C., "Minimal Encapsulation within IP", RFC 2004,
        October 1996

   [21] Atkinson, R., "IP Encapsulating Security Payload (ESP)", RFC
        1827, August 1995

   [22] Hanks, S., Li, T., Farinacci, D., Traina, P., "Generic Routing
        Encapsulation (GRE)", RFC 1701, October 1994

   [23] Simpson, W., "IP in IP Tunneling", RFC 1853, October 1995

   [24] M. Beadles, D. Mitton, "Criteria for Evaluating Network Access
        Server Protocols", draft-ietf-nasreq-criteria-05.txt, IETF work
        in progress, June 2000.

   [25] L. J. Blunk, J. R. Vollbrecht, "PPP Extensible Authentication
        Protocol (EAP)." RFC 2284, March 1998.

   [26] G. Zorn, P. R. Calhoun, "Limiting Fraud in Roaming", draft-
        ietf-roamops-fraud-limit-00.txt, IETF work in progress, May
        1999.

   [27] Narten, Alvestrand, "Guidelines for Writing an IANA Considera-
        tions Section in RFCs", BCP 26, RFC 2434, October 1998

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

   [29] F. Yergeau, "UTF-8, a transformation format of ISO 10646", RFC
        2279, January 1998.

   [30] P. Calhoun, C. Perkins, "Diameter Mobile IP Extensions", draft-
        ietf-aaa-diameter-mobileip-04.txt, IETF work in progress, May
        2001.

   [31] P. Calhoun, "Diameter Resource Management", draft-calhoun-
        diameter-res-mgmt-06.txt, IETF Work in Progress, February 2001.

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

   [33] G. Zorn, D. Leifer, A. Rubens, J. Shriver, M. Holdrege, I. Goy-
        ret, "RADIUS Attributes for Tunnel Protocol Support", RFC 2868,
        June 2000.

   [34] IANA, "RADIUS Types", http://www.isi.edu/in-



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        notes/iana/assignments/radius-types

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

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

   [37] G. Zorn, D. Leifer, A. Rubens, J. Shriver, M. Holdrege, I. Goy-
        ret, "RADIUS Attributes for Tunnel Protocol Support", RFC 2868,
        June 2000.


15.0  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, from which much of the concepts in this specification were
   derived from.  Also Carl Rigney and Ward Willats for [32], and Glen
   Zorn, Dory Leifer, Allan C. Rubens, John Shriver, Matt Holdrege and
   Ignacio Goyret for their work on [33]. This document stole text and
   concepts from both [32] and [33].

   The authors would also like to acknowledge the following people for
   their contribution in the development of the Diameter protocol:

   Bernard Aboba, Jari Arkko, William Bulley, Daniel C. Fox, Lol Grant,
   Nancy Greene, Peter Heitman, Paul Krumviede, Fergal Ladley, Ryan
   Moats, Victor Muslin, Kenneth Peirce, Sumit Vakil, John R. Vollbrecht
   and Jeff Weisberg


16.0  Authors' Addresses

   Questions about this memo can be directed to:

      Pat R. Calhoun
      Network and Security Research Center, Sun Labs
      Sun Microsystems, Inc.
      15 Network Circle
      Menlo Park, California, 94025
      USA

       Phone:  +1 650-786-7733
         Fax:  +1 650-786-6445
      E-mail:  pcalhoun@eng.sun.com


      William Bulley



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      Merit Network, Inc.
      Building One, Suite 2000
      4251 Plymouth Road
      Ann Arbor, Michigan  48105-2785
      USA

       Phone:  +1 734-764-9993
         Fax:  +1 734-647-3185
      E-mail:  web@merit.edu


      Allan C. Rubens
      Tut Systems, Inc.
      220 E. Huron, Suite 260
      Ann Arbor, MI 48104
      USA

       Phone:  +1 734-995-1697
      E-Mail:  arubens@tutsys.com


      Jeff Haag
      Cisco Systems
      7025 Kit Creek Road
      PO Box 14987
      Research Triangle Park, NC 27709

       Phone:  1-919-392-2353
      E-Mail:  haag@cisco.com


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

      Phone:  +1 425 438 8218
     E-Mail:  gwz@cisco.com


17.0  Full Copyright Statement

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published



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   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works. However, this docu-
   ment itself may not be modified in any way, such as by removing the
   copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of develop-
   ing Internet standards in which case the procedures for copyrights
   defined in the Internet Standards process must be followed, or as
   required to translate it into languages other than English. The lim-
   ited permissions granted above are perpetual and will not be revoked
   by the Internet Society or its successors or assigns. This document
   and the information contained herein is provided on an "AS IS" basis
   and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DIS-
   CLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
   TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT
   INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR
   FITNESS FOR A PARTICULAR PURPOSE.


18.0  Expiration Date

   This memo is filed as <draft-ietf-aaa-diameter-nasreq-04.txt> and
   expires in October 2001.




























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