RFC 3438

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

Title block, bestie: this is RFC 3438 💖, filed under the Network Working Group 🧚 by W. Townsley of Cisco Systems 💅. It's a Best Current Practice (that's BCP 68 👑), dated December 2002. The title block doesn't list anything it obsoletes or updates, so no drama there 🙈.

---

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 🌸

Okay so this doc is all about updating the Internet Assigned Numbers Authority (IANA) considerations for the Layer Two Tunneling Protocol (L2TP). Iconic energy ✨.

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 🍓

So this document gives IANA its guidance on registering values for L2TP, which is defined in [RFC2661], following BCP 26, [RFC2434]. Main character energy 💅.

1.1 Terminology 📚

The terms here mean what BCP 26 says they mean: "name space", "assigned value", "registration" 🔥.

The policies here also mean what BCP 26 says: "Private Use", "First Come First Served", "Expert Review", "Specification Required", "IETF Consensus", "Standards Action" 🫶.

2. IANA Considerations 👑

Okay, L2TP [RFC2661] has a bunch of "magic" numbers that IANA keeps track of. This section updates the criteria IANA uses to assign new numbers to each of those lists 💖.

Every value this document talks about, the ones that need a registration criteria update, is currently kept by IANA and runs from 0 to 65 535. Only a tiny handful are taken, and the most allocated in any one range is 46 [L2TP-IANA] 🌈. Honestly these values are never going to run out of room, even if the registration rules get relaxed from where they are now 🙈.

The recommended changes are in the sections below. In one case, the criteria are currently First Come First Served and should get stricter 😤. Others are IETF Consensus and need to loosen up. Why loosen? Because values that were never meant to be vendor-specific ended up in early field trials or shipped products as vendor-specific values, while people waited for the documents to get formalized. Result: products end up supporting both the vendor-specific value and the IETF value forever 😭.

When a registration request needs a Designated Expert, the responsible IESG Area Director should appoint that Designated Expert 🧚.

When a registration request needs Expert Review, the Designated Expert should consult the relevant WGs as appropriate (for example, the l2tpext WG at the time of writing) 🦋.

The basic guideline for Expert Review: approve a value only if there's a document being advanced that clearly defines the values to be assigned, AND there's active implementation development (maybe entering early field or interoperability trials, where assigned values let things move forward without falling back on a chosen vendor-specific method) 💅.

2.1 Control Message AVPs 🎀

IANA manages the "Control Message Attribute Value Pairs" [L2TP-IANA] name space, and 0 - 46 have been assigned. The criteria were 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, and 0 - 16 have been assigned. The criteria were originally IETF Consensus. Further values should be assigned upon Expert Review ✨.

2.3 Result Code AVP Values 🍓

IANA keeps 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 were originally First Come First Served. 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 🧚

Every L2TP criterion that IANA maintains and that isn't specifically mentioned in this document stays exactly the same 💖.

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

4. Security Considerations 💀

Real talk, bestie: this focuses on IANA considerations, and it does not have security considerations 😭. Take it seriously anyway, because the stakes of this section are not nothing 🫶.

5. Acknowledgements 🫶

Some of this text and much of the format of this document came from an internet document on EAP IANA Considerations, written by Bernard Aboba. Thank you, Bernard 💜✨.

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

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. 🌈