Network Working Group                                              Y. Li
Internet-Draft                                                   A. Lior
Intended status: Standards Track                                     BWS
Expires: September 8, 2009                                  G. Zorn, Ed.
                                                             Network Zen
                                                           March 7, 2009


Extended Remote Authentication Dial In User Service (RADIUS) Attributes
              draft-ietf-radext-extended-attributes-06.txt

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.  This document may contain material
   from IETF Documents or IETF Contributions published or made publicly
   available before November 10, 2008.  The person(s) controlling the
   copyright in some of this material may not have granted the IETF
   Trust the right to allow modifications of such material outside the
   IETF Standards Process.  Without obtaining an adequate license from
   the person(s) controlling the copyright in such materials, this
   document may not be modified outside the IETF Standards Process, and
   derivative works of it may not be created outside the IETF Standards
   Process, except to format it for publication as an RFC or to
   translate it into languages other than English.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

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

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on September 8, 2009.

Copyright Notice

   Copyright (c) 2009 IETF Trust and the persons identified as the
   document authors.  All rights reserved.



Li, et al.              Expires September 8, 2009               [Page 1]


Internet-Draft         Extended RADIUS Attributes             March 2009


   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents in effect on the date of
   publication of this document (http://trustee.ietf.org/license-info).
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.

Abstract

   For the Remote Authentication Dial In User Service (RADIUS) protocol
   to continue to support new applications, the RADIUS attribute type
   space must be extended beyond the current limit of 255 possible
   attribute types while maintaining backwards compatibility with the
   existing protocol.  This document defines a mechanism to accomplish
   that task, along with standard methods to group together related
   attributes and to encode values that don't fit into 253 octets.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  3
     2.1.  Requirements Language  . . . . . . . . . . . . . . . . . .  3
   3.  Problem Statement  . . . . . . . . . . . . . . . . . . . . . .  4
   4.  RADIUS Type Extension  . . . . . . . . . . . . . . . . . . . .  4
   5.  Formal Syntax  . . . . . . . . . . . . . . . . . . . . . . . .  5
   6.  Examples . . . . . . . . . . . . . . . . . . . . . . . . . . .  7
   7.  Diameter Considerations  . . . . . . . . . . . . . . . . . . . 11
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 11
   9.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 11
   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
     10.1. Normative References . . . . . . . . . . . . . . . . . . . 12
     10.2. Informative References . . . . . . . . . . . . . . . . . . 12
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12


















Li, et al.              Expires September 8, 2009               [Page 2]


Internet-Draft         Extended RADIUS Attributes             March 2009


1.  Introduction

   The Remote Authentication Dial In User Service (RADIUS) Protocol
   [RFC2865] defines two classes of attributes: standard and vendor-
   specific.

   Vendor-specific Attributes (VSAs) allow vendors (including Standards
   Development Organizations (SDOs)) to define their own Attributes,
   which may not be suitable for general usage; on the other hand, the
   attributes that belong to the standard RADIUS space are controlled by
   the IETF and are intended to be of general utility.  These attributes
   are defined in RFCs and are assigned type codes by the Internet
   Assigned Number Authority (IANA)[IANA].

   The standard RADIUS attribute type code is 8 bits in length; hence
   RADIUS is limited to 255 attribute types.  Of these 255 attribute
   types, approximately 101 have been assigned as of this writing.
   According to RFC 3575 [RFC3575], types 192-223 are reserved for
   experimental use; types 224-240 are reserved for implementation-
   specific use; and values 241-255 are reserved and should not be used.
   Therefore, as of this writing there are approximately 90 type codes
   that can be allocated to new attributes.

   RADIUS evolution must not be hindered by the inability to define new
   standard RADIUS attributes.  This document defines a mechanism to
   extend the standard RADIUS Attribute space by defining a new scheme
   to allocate attribute type codes.  In addition, mechanisms are
   defined to support both the grouping of related attributes and the
   encoding of attribute values the length of which exceed the current
   limit of 253 octets.


2.  Terminology

   Extended Attribute
      The term used for the new RADIUS attributes that are defined in
      this document

   Extended Type
      The type code assigned to an Extended Attribute

2.1.  Requirements Language

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



Li, et al.              Expires September 8, 2009               [Page 3]


Internet-Draft         Extended RADIUS Attributes             March 2009


   An implementation is not compliant if it fails to satisfy one or more
   of the must or must not requirements for the protocols it implements.
   An implementation that satisfies all the MUST, MUST NOT, SHOULD, and
   SHOULD NOT requirements for its protocols is said to be
   "unconditionally compliant"; one that satisfies all the MUST and MUST
   NOT requirements but not all the SHOULD or SHOULD NOT requirements
   for its protocols is said to be "conditionally compliant".


3.  Problem Statement

   A fundamental requirement for extending the RADIUS attribute space is
   the maintenance of backwards compatibility.  This means that RADIUS
   servers and proxies must be able to continue to decode and encode
   messages even though they may not need to understand an attribute
   that has been extended.  More specifically, the scheme MUST be
   compliant with the various RADIUS RFCs such as [RFC2865] and RADIUS
   Accounting [RFC2866], etc.

   The scheme SHOULD ensure that the size of the standard type space
   extension is large enough that it will not be quickly exhausted or is
   extensible in the event that it is.

   Furthermore, the scheme SHOULD align with the Diameter NASReq
   Application [RFC4005], thereby allowing the two AAA standards to
   interoperate.

   A need to group related RADIUS attributes together has become
   prevalent in current work.  Therefore, the proposed scheme SHOULD
   provide a mechanism to group related attributes together.

   In recent years, attribute sizes have been pushing the current limit
   of 253 octets.  Fragmentation of RADIUS attributes has always been
   possible by extending the value into another attribute of the same
   type; however, this approach does not always work (for example, if
   more than one instance of an attribute occurs in the same RADIUS
   packet).  The proposed scheme SHOULD enable the transmission of
   attributes longer than 253 octets.


4.  RADIUS Type Extension

   The solution described in this document takes the recommended VSA
   format [RFC2865] as a basis for the RADIUS Extended Attributes.

   We allocate RADIUS the Vendor-Id of zero (0).  In essence we are
   assigning the IETF a Vendor-Id which is what other SDOs have done in
   registering their own Vendor-Id.



Li, et al.              Expires September 8, 2009               [Page 4]


Internet-Draft         Extended RADIUS Attributes             March 2009


   Extended Attributes consist of an attribute header similar to that
   recommended by RFC 2865 [RFC2865] for Vendor Specific Attributes
   followed by a non-empty sequence of Type-Length-Value (TLV) triples
   (see below).  If an Extended Attribute contains more than one TLV
   then all of the encapsulated TLVs MUST fit completely within the
   Extended Attribute.

   The Extended Attribute header is 7 octets in length and is encoded as
   follows:

   o  The first octet contains the Type which is always Vendor-Specific
      (26)

   o  The second octet contains the length (in octets) of the entire
      Extended Attribute, including the Extended Attribute header and
      all encapsulated TLVs

   o  The next 4 octets contain the Vendor-Id (0)

   o  The final octet of the header contains the More flag and Tag
      field.  If the one-bit More flag is set (1) this indicates that
      the encapsulated TLV is continued in the following Extended
      Attribute; if the More flag is clear (0) then all of the
      encapsulated TLVs fit into the current Extended Attribute.  The
      More flag MUST NOT be set if the Extended Attribute contains more
      than one TLV.  The Tag field is used to combine sets of related
      Extended Attributes into simple, one level groups.

   o  The Data field is an abstract container for TLVs; the Data field
      MUST contain at least one TLV.

   TLVs are encoded as follows:

   o  The first two octets contain the Ext-Type field

   o  The next octet is the Ext-Len field, representing the length in
      octets of the entire TLV, including the length of the Ext-Type
      field (2 octets), the length of the Ext-Len field itself (1 octet)
      and the length of the Value field (1 or more octets)

   o  The Value field consists of one or more octets comprising the
      actual data to be transmitted


5.  Formal Syntax

   This section describes the encoding scheme used for RADIUS Extended
   Attributes.  The basis of this encoding is the format recommended for



Li, et al.              Expires September 8, 2009               [Page 5]


Internet-Draft         Extended RADIUS Attributes             March 2009


   Vendor Specific Attributes in RFC 2865 [RFC2865].

                        1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Type (26)   |  Length       |      Vendor-Id (0)            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          Vendor-Id (0)        |M|     Tag     |    Data...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      26 for Vendor-Specific

   Length

      > 10

   Vendor ID

      The Vendor Id field is 4 octets in length and MUST be zero
      (0x0000), signifying an extended IETF RADIUS attribute

   M (More)

      The More Flag is one (1) bit in length and MUST be present.  When
      a value to be transmitted exceeds 245 octets in length it is
      fragmented over two or more Extended Attributes.  If the More Flag
      is set (1), this indicates that the Value field of the Extended
      Attribute contains a fragment of a larger value, which MUST be
      continued in the next Extended Attribute of the same Ext-Type.
      When the More Flag is clear (0), the final (or only) fragment of
      the value is contained in the Extended Attribute.  The More Flag
      MUST NOT be set if the Length is less than 255.  Any Extended
      Attributes containing multiple fragments of the same value MUST be
      in order and MUST be consecutive attributes in the packet.

   Tag

      The Tag field is 7 bits long and MUST be present.  It is used to
      group Extended Attributes.  Extended Attributes with the same non-
      zero value in the Tag field belong to the same group.  A Tag value
      of zero (0) indicates that the attribute is not grouped.  A Tag
      value of all ones (0x7F) is reserved.







Li, et al.              Expires September 8, 2009               [Page 6]


Internet-Draft         Extended RADIUS Attributes             March 2009


   Data

      The Data field is >= 4 octets in length.  It consists of 1 or more
      TLVs.

   TLVs have the following syntax:

                        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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Ext-Type           |    Ext-Len    |    Value...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Ext-Type

      Two (2) octets.  Up-to-date values of the Ext-Type field are
      specified in the most recent "Assigned Numbers" [IANA].  Values
      64512-65535 (0xFC00-0xFFFF) are reserved.

   Ext-Len

      > 3.  The length of the Type-Length-Value tuple in octets,
      including the Ext-Type, Ext-Len and Value fields.

   Value

      One or more octets.


6.  Examples

   Consider an attribute called Foo of type String.  Foo has been
   allocated an Extended-Type of 257 by IANA.  The following figure
   illustrates the encoding of the string "Hello":

















Li, et al.              Expires September 8, 2009               [Page 7]


Internet-Draft         Extended RADIUS Attributes             March 2009


                        1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Type (26)   |    Length     |          Vendor-Id
   |               | (7 + 8 = 15)  |             (0)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
           Vendor-Id (cont)        |M|    Tag      |   Ext-Type
                                   |0|    (0)      |    (0X01)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    Ext-Type (cont)|    Ext-Len    |     Value     |               |
        (0X01)     |  (3 + 5 = 8)  |      (H)      |      (e)      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               |               |               |
   |      (l)      |      (l)      |      (o)      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 1

   Now consider another instantiation of the Foo Extended Attribute,
   this one with a length of 251 octets.  In this case the value is
   fragmented over two Extended Attributes.  The first 245 octets are
   included in the first fragment which has the More bit set and the
   remaining 6 octets appear in the second attribute.  Figure 2 below
   illustrates the encoding of the first 7 octets of the first Extended
   Attribute, while Figure 3 shows how the second attribute (containing
   the string "e end.") is encoded.

                        1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Type (26)   |    Length     |          Vendor-Id
   |               |(7 + 248 = 255)|             (0)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
          Vendor-Id (cont)         |M|    Tag      |    Ext-Type
                (0)                |1|    (0)      |     (0X01)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    Ext-Type (cont)|    Ext-Len    |     Value     |               |
        (0X01)     |(3 + 245 = 248)|      (H)      |      (e)      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               |               |               |               |
   |      (l)      |      (l)      |      (o)      |     ( )       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               |
   |      (W)      |      ...
   +-+-+-+-+-+-+-+-+

                                 Figure 2




Li, et al.              Expires September 8, 2009               [Page 8]


Internet-Draft         Extended RADIUS Attributes             March 2009


                        1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Type (26)   |    Length     |          Vendor-Id
   |               | (7 + 9  = 16) |             (0)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
           Vendor-Id (cont)        |M|    Tag      |    Ext-Type
                  (0)              |0|    (0)      |     (0X00)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    Ext-Type (cont)|    Ext-Len    |     Value     |               |
        (0X01)     |  (3 + 6 = 9)  |      (e)      |      ( )      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               |               |               |               |
   |      (e)      |     (n)       |      (d)      |      (.)      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 3

   The next example illustrates several of the features of Extended
   Attributes:

   o  encapsulation of values greater than 253 octets in length

   o  grouping of related Extended Attributes using tags

   o  encapsulation of more than one TLV in a single Extended Attribute

   Consider the following structure:

     struct
       Integer a;
       String  b;
       Integer c;
     endStruct

   Element 'a' is assigned an Extended Type of 290 (0x0122).  Element
   'b' is assigned an Extended Type of 259 (0x0103) and element 'c' is
   assigned an Extended Type of 271 (0x010F).  The following figure
   illustrates the encoding where the value of 'a' contains 0xDEADDEAD,
   the first two octets of 'b' contain the string "He", octets 243-250
   of 'b' contain "The end." and the value of 'c' is 0x12345678.  The
   attributes are grouped together with TAG=42.  Note that this encoding
   is only one out of several possibilities since there is no strict
   order in attribute marshalling; for the sake of brevity, octets 3-241
   of the value of 'b' are omitted from the diagram.






Li, et al.              Expires September 8, 2009               [Page 9]


Internet-Draft         Extended RADIUS Attributes             March 2009


                        1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Type (26)   |    Length     |          Vendor-Id
   |               | (7 + 7 = 14)  |             (0)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
           Vendor-Id (cont)        |M|    Tag      |    Ext-Type
                 (0)               |0|    (42)     |     (0x01)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    Ext-Type (cont)|    Ext-Len    |     Value     |               |
        (0x22)     |  (3 + 4 = 7)  |     (0xDE)    |    (0xAD)     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               |               |
   |     (0xDE)    |      (0xAD)   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                        1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Type (26)   |    Length     |          Vendor-Id
   |               |(7 + 248 = 255)|             (0)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
             Vendor-Id (cont)      |M|    Tag      |    Ext-Type
                  (0)              |1|    (42)     |     (0x01)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    Ext-Type (cont)|    Ext-Len    |     Value     |               |
        (0x03)     |(3 + 245 = 248)|      (H)      |      (e)      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ...
                        1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Type (26)   |    Length     |          Vendor-Id
   |               |  (7+8 = 15)   |             (0)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
           Vendor-Id (cont)        |M|    Tag      |    Ext-Type
                 (0)               |0|    (42)     |     (0x01)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    Ext-Type (cont)|     Ext-Len   |     Value     |               |
        (0x03)     |   (3 + 5 = 8) |      ( )      |      (e)      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               |               |               |
   |      (n)      |      (d)      |      (.)      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+






Li, et al.              Expires September 8, 2009              [Page 10]


Internet-Draft         Extended RADIUS Attributes             March 2009


                        1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Type (26)   |    Length     |          Vendor-Id
   |               |  (7+7 = 14)   |             (0)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
           Vendor-Id (cont)        |M|    Tag      |    Ext-Type
                 (0)               |0|    (42)     |     (0x01)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    Ext-Type (cont)|     Ext-Len   |     Value     |               |
        (0x0F)     |   (3 + 4 = 7) |     (0x12)    |    (0x34)     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               |               |
   |    (0x56)     |     (0x78)    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 4


7.  Diameter Considerations

   Since the Extended Attributes are encoded as Vendor-Specific RADIUS
   Attributes (see [IANA]), no special handling is required by Diameter
   [RFC3588] entities; see [RFC4005] for details on the Diameter
   treatment of RADIUS VSAs.


8.  Security Considerations

   This document does not introduce any new security issues into the
   RADIUS protocol; for known security problems with RADIUS, see
   [RFC2865], [RFC2869] and [RFC2607].


9.  IANA Considerations

   This standard requires that the Vendor-Id of zero be allocated to the
   IETF.

   It also requires that IANA set up a new registry for the RADIUS
   Extended Types, reserving the values 64512-65535 (0xFC00-0xFFFF) for
   future purposes.  Values in this registry should be allocated using
   the "IETF Review" policy [RFC5226].


10.  References





Li, et al.              Expires September 8, 2009              [Page 11]


Internet-Draft         Extended RADIUS Attributes             March 2009


10.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

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

10.2.  Informative References

   [IANA]     Internet Assigned Number Authority, "RADIUS TYPES",
              August 2008,
              <http://www.iana.org/assignments/radius-types>.

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

   [RFC2866]  Rigney, C., "RADIUS Accounting", RFC 2866, June 2000.

   [RFC2869]  Rigney, C., Willats, W., and P. Calhoun, "RADIUS
              Extensions", RFC 2869, June 2000.

   [RFC3575]  Aboba, B., "IANA Considerations for RADIUS (Remote
              Authentication Dial In User Service)", RFC 3575,
              July 2003.

   [RFC3588]  Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J.
              Arkko, "Diameter Base Protocol", RFC 3588, September 2003.

   [RFC4005]  Calhoun, P., Zorn, G., Spence, D., and D. Mitton,
              "Diameter Network Access Server Application", RFC 4005,
              August 2005.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008.














Li, et al.              Expires September 8, 2009              [Page 12]


Internet-Draft         Extended RADIUS Attributes             March 2009


Authors' Addresses

   Yong Li
   Bridgewater Systems Corporation
   303 Terry Fox Drive
   Suite 100
   Ottawa, Ontario  K2K 3J1
   Canada

   Phone: +1 (613) 591-6655
   Email: yongli@bridgewatersystems.com
   URI:   http://www.bridgewatersystems.com/


   Avi Lior
   Bridgewater Systems Corporation
   303 Terry Fox Drive
   Suite 100
   Ottawa, Ontario  K2K 3J1
   Canada

   Phone: +1 (613) 591-6655
   Email: avi@bridgewatersystems.com
   URI:   http://www.bridgewatersystems.com/


   Glen Zorn (editor)
   Network Zen
   1310 East Thomas Street
   Seattle, Washington  98102
   US

   Phone: +1 (206) 377-9035
   Email: gwz@net-zen.net

















Li, et al.              Expires September 8, 2009              [Page 13]