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rfc:rfc3438

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].

Townsley Best Current Practice [Page 1] 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

Townsley Best Current Practice [Page 2] 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

Townsley Best Current Practice [Page 3] RFC 3438 L2TP IANA Considerations December 2002

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

Townsley Best Current Practice [Page 4] 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.

Townsley Best Current Practice [Page 5]

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