





Network Working Group                                        W. Townsley
Request for Comments: 3438                                 Cisco Systems
BCP: 68                                                    December 2002
Category: Best Current Practice


                  Layer Two Tunneling Protocol (L2TP)
    Internet Assigned Numbers Authority (IANA) Considerations Update

Status of this Memo

   This document specifies an Internet Best Current Practices for the
   Internet Community, and requests discussion and suggestions for
   improvements.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.

Abstract

   This document describes updates to the Internet Assigned Numbers
   Authority (IANA) considerations for the Layer Two Tunneling Protocol
   (L2TP).

Table of Contents

   1. Introduction.............................................    1
     1.1 Terminology...........................................    2
   2. IANA Considerations......................................    2
     2.1 Control Message AVPs..................................    3
     2.2 Message Type AVP Values...............................    3
     2.3 Result Code AVP Values................................    3
     2.4 Remaining Values......................................    3
   3. Normative References.....................................    3
   4. Security Considerations..................................    4
   5. Acknowledgements.........................................    4
   6. Author's Address.........................................    4
   7. Full Copyright Statement.................................    5

1. Introduction

   This document provides guidance to the Internet Assigned Numbers
   Authority (IANA) regarding the registration of values related to the
   Layer Two Tunneling Protocol (L2TP), defined in [RFC2661], in
   accordance with BCP 26, [RFC2434].





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RFC 3438                L2TP IANA Considerations           December 2002


1.1 Terminology

   The following terms are used here with the meanings defined in
   BCP 26:  "name space", "assigned value", "registration".

   The following policies are used here with the meanings defined in
   BCP 26: "Private Use", "First Come First Served", "Expert Review",
   "Specification Required", "IETF Consensus", "Standards Action".

2. IANA Considerations

   L2TP [RFC2661] defines a number of "magic" numbers to be maintained
   by the IANA.  This section updates the criteria to be used by the
   IANA to assign additional numbers in each of these lists.

   Each of the values identified in this document that require a
   registration criteria update are currently maintained by IANA and
   have a range of values from 0 to 65 535, of which a very small number
   have been allocated (the maximum number allocated within any one
   range is 46) [L2TP-IANA].  Given the nature of these values, it is
   not expected that any will ever run into a resource allocation
   problem if registration allocation requirements are relaxed from
   their current state.

   The recommended criteria changes for IANA registration are listed in
   the following sections.  In one case, the registration criteria is
   currently defined as First Come First Served and should be made more
   strict, others are defined as IETF Consensus and need to be relaxed.
   The relaxation from IETF Consensus is motivated by specific cases in
   which values that were never intended to be vendor-specific have had
   to enter early field trials or be released in generally available
   products with vendor-specific values while awaiting documents to be
   formalized.  In most cases, this results in products that have to
   support both the vendor-specific value and IETF value indefinitely.

   For registration requests where a Designated Expert should be
   consulted, the responsible IESG Area Director should appoint the
   Designated Expert.

   For registration requests requiring Expert Review, the Designated
   Expert should consult relevant WGs as appropriate (e.g., the l2tpext
   WG at the time of this writing).

   The basic guideline for the Expert Review process will be to approve
   the assignment of a value only if there is a document being advanced
   that clearly defines the values to be assigned, and there is active





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RFC 3438                L2TP IANA Considerations           December 2002


   implementation development (perhaps entering early field or
   interoperability trails, requiring assigned values to proceed without
   having to resort to a chosen vendor-specific method).

2.1 Control Message AVPs

   IANA manages the "Control Message Attribute Value Pairs" [L2TP-IANA]
   name space, of which 0 - 46 have been assigned.  The criteria for
   assignment was originally IETF Consensus.  Further values should be
   assigned upon Expert Review.

2.2 Message Type AVP Values

   IANA manages the "Message Type AVP (Attribute Type 0) Values" [L2TP-
   IANA] name space, of which 0 - 16 have been assigned.  The criteria
   for assignment was originally IETF Consensus.  Further values should
   be assigned upon Expert Review.

2.3 Result Code AVP Values

   IANA maintains a list of "Result Code values for the StopCCN
   message," "Result Code values for the CDN message," and "General
   Error Codes" [L2TP-IANA].  The criteria for Error Code assignment was
   originally First Come First Served, and the criteria for CDN and
   StopCCN Result Codes were originally IETF Consensus.  Further values
   for all Result and Error codes should be assigned upon Expert Review.

2.4 Remaining Values

   All criteria for L2TP values maintained by IANA and not mentioned
   specifically in this document remain unchanged.

3. Normative References

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

   [RFC2434]   Alvestrand, H. and T. Narten, "Guidelines for Writing an
               IANA Considerations Section in RFCs", BCP 26, RFC 2434,
               October 1998.

   [RFC2661]   Townsley, W., Valencia, A., Rubens, A., Pall, G., Zorn,
               G. and B. Palter, "Layer Two Tunneling Layer Two
               Tunneling Protocol (L2TP)", RFC 2661, August 1999.

   [L2TP-IANA] Internet Assigned Numbers Authority (IANA), "Layer Two
               Tunneling Protocol 'L2TP' - RFC 2661",
               http://www.iana.org/assignments/l2tp-parameters



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4. Security Considerations

   This focuses on IANA considerations, and does not have security
   considerations.

5. Acknowledgements

   Some of this text and much of the format of this document was taken
   from an internet document on EAP IANA Considerations authored by
   Bernard Aboba.

6. Author's Address

   W. Mark Townsley
   Cisco Systems
   7025 Kit Creek Road
   PO Box 14987
   Research Triangle Park, NC 27709

   EMail: mark@townsley.net































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RFC 3438                L2TP IANA Considerations           December 2002


7.  Full Copyright Statement

   Copyright (C) The Internet Society (2002).  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
   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
   document 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
   developing 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 limited 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 DISCLAIMS 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.

Acknowledgement

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



















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