Uncoordinated Protocol Development Considered Harmful
RFC 5704

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Network Working Group                                     S. Bryant, Ed.
Request for Comments: 5704                                M. Morrow, Ed.
Category: Informational                                      For the IAB
                                                           November 2009

         Uncoordinated Protocol Development Considered Harmful

Abstract

   This document identifies problems that may result from the absence of
   formal coordination and joint development on protocols of mutual
   interest between standards development organizations (SDOs).  Some of
   these problems may cause significant harm to the Internet.  The
   document suggests that a robust procedure is required prevent this
   from occurring in the future.  The IAB has selected a number of case
   studies, such as Transport MPLS (T-MPLS), as recent examples to
   describe the hazard to the Internet architecture that results from
   uncoordinated adaptation of a protocol.

   This experience has resulted in a considerable improvement in the
   relationship between the IETF and the ITU-T.  In particular, this was
   achieved via the establishment of the "Joint working team on
   MPLS-TP".  In addition, the leadership of the two organizations
   agreed to improve inter-organizational working practices so as to
   avoid conflict in the future between ITU-T Recommendations and IETF
   RFCs.

   Whilst we use ITU-T - IETF interactions in these case studies, the
   scope of the document extends to all SDOs that have an overlapping
   protocol interest with the IETF.

Status of This Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (c) 2009 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

Bryant, et al.               Informational                      [Page 1]
RFC 5704                 Uncoordinated Harmful             November 2009

   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 BSD License.

Table of Contents

   1. Introduction ....................................................2
   2. Protocol Design Rules ...........................................3
      2.1. Protocol Safety ............................................3
      2.2. Importance of Invariants ...................................4
      2.3. Importance of Correct Identification .......................4
      2.4. The Role of the Design Authority ...........................4
      2.5. Ships in the Night .........................................5
   3. Examples of Miscoordination .....................................6
      3.1. T-MPLS as a Case Study .....................................6
      3.2. PPP over SONET/SDH (Synchronous Optical Network /
           Synchronous Digital Hierarchy ..............................6
   4. Managing Information Flow .......................................7
      4.1. Managing Information Flow within an SDO ....................7
      4.2. Managing Information Flow between SDOs .....................7
   5. MPLS-TP as Best Practice ........................................7
   6. IETF Change Process .............................................8
   7. Security Considerations .........................................8
   8. Acknowledgments .................................................8
   9. IAB Members at the Time of This Writing .........................8
   10. Emerging Issues ................................................9
   11. Conclusion .....................................................9
   12. Informative References .........................................9
   Appendix A.  A Review of the T-MPLS Case ..........................12
     A.1.  Multiple Definitions of Label 14 ..........................12
     A.2.  Redefinition of TTL Semantics .............................13
     A.3.  Reservation of Additional Labels ..........................13
     A.4.  Redefinition of MPLS EXP Bits .............................14
     A.5.  The Consequences for the Network Operators ................14
     A.6.  The Consequences for the SDOs .............................15

1.  Introduction

   The uncoordinated adaptation of a protocol, parameter, or code-point
   by a standards development organization (SDO), either through the
   allocation of a code-point without following the formal registration
   procedures or by unilaterally modifying the semantics of the protocol