Deprecating Use of the "X-" Prefix in Application Protocols
draft-ietf-appsawg-xdash-03

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Document Type Active Internet-Draft (appsawg WG)
Last updated 2012-03-06 (latest revision 2012-02-13)
Replaces draft-saintandre-xdash
Stream IETF
Intended RFC status Best Current Practice
Formats plain text pdf html
Stream WG state Submitted to IESG for Publication
Consensus Unknown
Document shepherd Alexey Melnikov
Shepherd write-up Show (last changed 2012-02-22)
IESG IESG state In Last Call (ends 2012-03-15)
Telechat date
Needs 4 more YES or NO OBJECTION positions to pass.
Responsible AD Pete Resnick
Send notices to appsawg-chairs@tools.ietf.org, draft-ietf-appsawg-xdash@tools.ietf.org
APPSAWG                                                   P. Saint-Andre
Internet-Draft                                       Cisco Systems, Inc.
Intended status: BCP                                          D. Crocker
Expires: August 16, 2012                     Brandenburg InternetWorking
                                                           M. Nottingham
                                                               Rackspace
                                                       February 13, 2012

      Deprecating Use of the "X-" Prefix in Application Protocols
                      draft-ietf-appsawg-xdash-03

Abstract

   Historically, designers and implementers of application protocols
   have often distinguished between "standard" and "non-standard"
   parameters by prefixing the latter with the string "X-" or similar
   constructions.  In practice, this convention causes more problems
   than it solves.  Therefore, this document deprecates the "X-"
   convention for textual parameters in application protocols.

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
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   This Internet-Draft will expire on August 16, 2012.

Copyright Notice

   Copyright (c) 2012 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

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   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.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Recommendations for Implementers of Application Protocols  . .  3
   3.  Recommendations for Creators of New Parameters . . . . . . . .  3
   4.  Recommendations for Protocol Designers . . . . . . . . . . . .  4
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . .  4
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  5
   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .  5
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . .  5
     8.1.  Normative References . . . . . . . . . . . . . . . . . . .  5
     8.2.  Informative References . . . . . . . . . . . . . . . . . .  5
   Appendix A.  Background  . . . . . . . . . . . . . . . . . . . . .  7
   Appendix B.  Analysis  . . . . . . . . . . . . . . . . . . . . . .  9
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11

Saint-Andre, et al.      Expires August 16, 2012                [Page 2]
Internet-Draft                The X- Prefix                February 2012

1.  Introduction

   Many application protocols use parameters with textual names to
   identify data (media types, header fields in Internet mail messages
   and HTTP requests, vCard parameters and properties, etc.).
   Historically, designers and implementers of application protocols
   have often distinguished between "standard" and "non-standard"
   parameters by prefixing the latter with the string "X-" or similar
   constructions (e.g., "x."), where the "X" is commonly understood to
   stand for "eXperimental" or "eXtension".

   Although in theory the "X-" convention was a good way to avoid
   collisions (and attendant interoperability problems) between standard
   parameters and non-standard parameters, in practice the benefits have
   been outweighed by the costs associated with the leakage of non-
   standard parameters into the standards space.  Therefore this
   document deprecates the "X-" convention for named parameters in
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