Long-term Viability of Protocol Extension Mechanisms
draft-thomson-use-it-or-lose-it-00

Document Type Active Internet-Draft (individual)
Last updated 2017-09-11
Replaces draft-thomson-protocol-freedom
Stream (None)
Intended RFC status (None)
Formats plain text xml pdf html bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
Network Working Group                                         M. Thomson
Internet-Draft                                                   Mozilla
Intended status: Standards Track                      September 12, 2017
Expires: March 16, 2018

          Long-term Viability of Protocol Extension Mechanisms
                   draft-thomson-use-it-or-lose-it-00

Abstract

   The ability to change protocols depends on exercising the extension
   and version negotiation mechanisms that support change.  Protocols
   that don't use these mechanisms can find that deploying changes can
   be difficult and costly.

Status of This Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   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."

   This Internet-Draft will expire on March 16, 2018.

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
   (https://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.

Thomson                  Expires March 16, 2018                 [Page 1]
Internet-Draft              Use It Or Lose It             September 2017

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Implementations of Protocols are Imperfect  . . . . . . . . .   2
     2.1.  Good Protocol Design is Not Sufficient  . . . . . . . . .   3
     2.2.  Multi-Party Interactions and Middleboxes  . . . . . . . .   4
   3.  Retaining Viable Protocol Evolution Mechanisms  . . . . . . .   5
     3.1.  Practice Can Ensure Viability . . . . . . . . . . . . . .   5
     3.2.  Dependency is Better  . . . . . . . . . . . . . . . . . .   6
     3.3.  Unused Extension Points Become Unusable . . . . . . . . .   7
   4.  Defensive Design Principles for Protocols . . . . . . . . . .   7
     4.1.  Active Use  . . . . . . . . . . . . . . . . . . . . . . .   7
     4.2.  Grease  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     4.3.  Cryptography  . . . . . . . . . . . . . . . . . . . . . .   9
     4.4.  Visibility of Faults  . . . . . . . . . . . . . . . . . .   9
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
   7.  Informative References  . . . . . . . . . . . . . . . . . . .  10
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

   A successful protocol [SUCCESS] will change in ways that allow it to
   continue to fulfill the needs of its users.  New use cases,
   conditions and constraints on the deployment of a protocol can render
   a protocol that does not change obsolete.

   Usage patterns and requirements for a protocol shift over time.
   Protocols can react to these shifts in one of three ways: adjust
   usage patterns within the constraints of the protocol, extend the
   protocol, and replace the protocol.  These reactions are
   progressively more disruptive, but are also dictated by the nature of
   the change in requirements over longer periods.

   Experience with Internet-scale protocol deployment shows that
   changing protocols is not uniformly successful.  [TRANSITIONS]
   examines the problem more broadly.

   This document examines the specific conditions that determine whether
   protocol maintainers have the ability to design and deploy new or
   modified protocols.  Section 4 outlines several strategies that might
   aid in ensuring that protocol changes remain possible over time.

2.  Implementations of Protocols are Imperfect

   A change to a protocol can be made extremely difficult to deploy if
   there are bugs in implementations with which the new deployment needs
   to interoperate.  Bugs in the handling of new codepoints or

Thomson                  Expires March 16, 2018                 [Page 2]
Internet-Draft              Use It Or Lose It             September 2017

   extensions can mean that instead of handling the mechanism as
Show full document text