[Docs] [txt|pdf] [Tracker] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-chen-radext-extended-header) 00 01

Network Working Group                                           E. Chen
Internet Draft                                                  N. Shen
Intended Status: Standards Track                          Cisco Systems
Expiration Date: October 26, 2017                        April 25, 2017



                  RADIUS Extended Identifier Attribute
                draft-chen-radext-identifier-attr-01.txt


Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

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

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

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

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

   This Internet-Draft will expire on October 26, 2017.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors. All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document. Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document. Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.



Chen & Shen                                                     [Page 1]


Internet Draft  draft-chen-radext-identifier-attr-01.txt      April 2017


Abstract

   The limitation with the one-octet "Identifier" field in the RADIUS
   packet is well known. In this document we propose extensions to the
   RADIUS protocol to address this fundamental limitation, and thus
   allowing for more efficient and more scalable implementations.


1. Introduction

   The "Identifier" field in the RADIUS packet [RFC2865] is used to
   match outstanding requests and replies.  As the field is one octet in
   size, only 256 requests can be in progress between two endpoints,
   which would present a significant bottleneck for performance.  The
   workaround for this limitation is to use multiple source ports as
   documented and discussed in [RFC2865], [RFC3539], and [RFC6613].

   Currently it is quite common to have hundreds of parallel connections
   between a RADIUS client and a server, especially in the deployment of
   controllers for wireless clients.  As the scale requirement continues
   to increase, the number of "parallel connections" is expected to grow
   (perhaps reaching thousands), which will undoubtedly create a number
   of challenges with resource utilization, efficiency, and connection
   management (with RADIUS over TCP [RFC6613] in particular) on both the
   client and the server.

   In this document we propose extensions to the RADIUS protocol to
   address this fundamental limitation and thus allowing for more
   efficient and more scalable implementations. More specifically, a new
   attribute ("Extended Identifier Attribute") is defined that can be
   used to discover the support of this specification between a client
   and a server using the Status-Server message [RFC5997].  Once the
   support is confirmed, the attribute can then be used to carry the
   extended identifier parameter in subsequent RADIUS packets. The
   extended identifier parameter can be used together with the
   Identifier to match outstanding requests and replies.

   For brevity the extensions specified in this document are referred to
   as "the Extended Identifier feature" hereafter.


1.1. Specification of Requirements

   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].





Chen & Shen                                                     [Page 2]


Internet Draft  draft-chen-radext-identifier-attr-01.txt      April 2017


2. Protocol Extensions


2.1. The Extended Identifier Attribute

   A new attribute, termed "Extended Identifier Attribute", is specified
   which can be used to discover the support for the Extended Identifier
   feature between a client and a server. It can also be used to carry
   the "extended identifier" parameter in a RADIUS packet after the
   support is confirmed.  The attribute number is TBD.  The value of the
   attribute has 4 octets, and consists of the following fields:


     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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Sta|               Extended Identifier                         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   where the 2-bit Status field is to be used in a Status-Server message
   to discover the support for the Extended Identifier feature. The
   following settings are defined:

       o It is set to 1 (for "request") when a client sends the
         Status-Server request to a server indicating its support for
         the Extended Identifier feature.

       o It is set to 2 (for "accept") or 3 (for "reject") by the
         server in its response to indicate whether it supports the
         Extended Identifier feature.

   The 30-bit "Extended Identifier" field is an unsigned integer.  It is
   to be used together with the Identifier field to match outstanding
   requests and replies.

   When the "Extended Identifier Attribute" is used in a Status-Server
   request or reply, only the Status field is used. All other fields
   SHOULD be set to zero by the sender and MUST be ignored by the
   receiver.

   When the "Extended Identifier Attribute" is used in a message other
   than the Status-Server request or reply, the Status field is unused,
   and SHOULD be set to zero by the sender and MUST be ignored by the
   receiver.

   To simplify packet processing and for consistency, the "Extended
   Identifier Attribute" MUST be encoded as the very first attribute in



Chen & Shen                                                     [Page 3]


Internet Draft  draft-chen-radext-identifier-attr-01.txt      April 2017


   the attribute list of a RADIUS packet.  If the attribute does not
   appear as the first one in the attribute list of a RADIUS packet, the
   RADIUS packet MUST be treated as invalid and the packet be discarded
   according to [RFC2865].

   Due to the hop-by-hop nature of RADIUS packet transmission between
   RADIUS devices, a PROXY server MUST strip the "Extended Identifier
   Attribute" (and reconstruct if appropriate) before sending the packet
   over a different session.


2.2. Status-Server Considerations

   This section extends processing of Status-Server messages as
   described in Sections 4.1 and 4.2 of [RFC5997].

   Prior to sending a RADIUS packet (other than the Status-Server
   request) with the "Extended Identifier Attribute", a client
   implementing this specification SHOULD first send a Status-Server
   request with the "Extended Identifier Attribute" to indicate its
   support for the Extended Identifier feature.

   When a server implementing this specification receives a Status-
   Server request with the "Extended Identifier Attribute", it MUST
   include the "Extended Identifier Attribute" in its response to
   indicate whether it supports the Extended Identifier feature.  If the
   Status-server reply from a server does not contain the "Extended
   Identifier Attribute", the client MUST treat this case as "reject" by
   the server for the Extended Identifier feature.

   Unless specified by configuration, a client MUST NOT send a RADIUS
   packet (other than the Status-Server request) with the "Extended
   Identifier Attribute" to a server until it has received a response
   from the server confirming its support for the Extended Identifier
   feature using the "Extended Identifier Attribute".

   When TCP is used as the transport protocol for RADIUS [RFC6613]
   between a client and a server, the Extended Identifier feature SHOULD
   be discovered each time the TCP session is established.


2.3. Use of the Extended Identifier Field

   After the functionality defined in this specification is discovered
   between the client and the server, the Extended Identifier field can
   be carried using the "Extended Identifier Attribute" in a RADIUS
   packet. The Extended Identifier is to be used together with the
   Identifier to identify requests and replies.  The assignment of these



Chen & Shen                                                     [Page 4]


Internet Draft  draft-chen-radext-identifier-attr-01.txt      April 2017


   parameters is left to implementation.

   When the "Extended Identifier Attribute" is present in a RADIUS
   packet other than the Status-Server request or reply, the Extended
   Identifier field in the attribute MUST be used together with the
   Identifier field to identify requests and replies.

   In response to a request from a client that contains the Extended
   Identifier field, the server MUST include the Extended Identifier
   field with an identical value in its reply.


3. IANA Considerations

   A new attribute ("Extended Identifier Attribute") is defined for the
   RADIUS protocol. The type value [RFC3575] needs to be assigned using
   the assignment rules in section 10.3 of [RFC6929].


4. Security Considerations

   This document defines a new RADIUS attribute, which does not affect
   the security considerations of the RADIUS protocol [RFC2865].

   The new RADIUS attribute and the procedures described in this
   document helps eliminate the need for "parallel connections" between
   a RADIUS client and a server due to the limitation with the
   "Identifier" field.  Thus the resource utilization (such as the
   number of UDP/TCP ports) on a RADIUS device is expected to be reduced
   significantly in large scale deployment.


5. Acknowledgments

   We would like to thank Alan DeKok for useful discussions and
   suggestions.















Chen & Shen                                                     [Page 5]


Internet Draft  draft-chen-radext-identifier-attr-01.txt      April 2017


6. References


6.1. Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

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

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


6.2. Informative References

   [RFC3539]  Aboba, B. and J. Wood, "Authentication, Authorization
              and Accounting (AAA) Transport Profile", RFC 3539, June
              2003.

   [RFC6613]  DeKok, A., "RADIUS over TCP", RFC 6613, May 2012.

   [RFC5997]  DeKok, A., "Use of Status-Server Packets in the Remote
              Authentication Dial In User Service (RADIUS) Protocol",
              RFC 5997, August 2010.

   [RFC6929]  DeKok, A. and A. Lior, "Remote Authentication Dial In User
              Service (RADIUS) Protocol Extensions", RFC 6929, April
              2013.


7. Authors' Addresses

   Enke Chen
   Cisco Systems
   560 McCarthy Blvd.
   Milpitas, CA 95035
   USA

   Email: enkechen@cisco.com

   Naiming Shen
   Cisco Systems



Chen & Shen                                                     [Page 6]


Internet Draft  draft-chen-radext-identifier-attr-01.txt      April 2017


   560 McCarthy Blvd.
   Milpitas, CA 95035
   USA

   Email: naiming@cisco.com














































Chen & Shen                                                     [Page 7]


Html markup produced by rfcmarkup 1.124, available from https://tools.ietf.org/tools/rfcmarkup/