The IMAP APPENDLIMIT Extension
draft-ietf-imapapnd-appendlimit-extension-09

The information below is for an old version of the document
Document Type Active Internet-Draft (imapapnd WG)
Last updated 2016-01-07
Replaces draft-jayantheesh-imap-appendlimit-extension
Stream IETF
Intended RFC status Proposed Standard
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Stream WG state Submitted to IESG for Publication
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Shepherd write-up Show (last changed 2015-12-07)
IESG IESG state Approved-announcement to be sent::Point Raised - writeup needed
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Send notices to "S Moonesamy" <sm+ietf@elandsys.com>
IANA IANA review state Version Changed - Review Needed
Network Working Group                     J. SrimushnamBoovaraghamoorthy
Internet-Draft                                                  N. Bisht
Intended status: Standards Track             Samsung Electronics America
Expires: July 10, 2016                                   January 7, 2016

                     The IMAP APPENDLIMIT Extension
            draft-ietf-imapapnd-appendlimit-extension-09.txt

Abstract

   This document defines an extension to the IMAP service whereby a
   server can inform the client about maximum message upload sizes,
   allowing the client to avoid sending APPEND commands that will fail
   because the messages are too large.

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
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   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on July 10, 2016.

Copyright Notice

   Copyright (c) 2016 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
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   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.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Conventions and Terminology . . . . . . . . . . . . . . .   2
   2.  APPENDLIMIT Extension . . . . . . . . . . . . . . . . . . . .   3
   3.  Mailbox-specific APPENDLIMIT  . . . . . . . . . . . . . . . .   3
     3.1.  STATUS response to the STATUS command . . . . . . . . . .   4
     3.2.  STATUS response to the LIST command . . . . . . . . . . .   4
     3.3.  APPENDLIMIT behaviour . . . . . . . . . . . . . . . . . .   4
   4.  APPEND response . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Formal syntax . . . . . . . . . . . . . . . . . . . . . . . .   5
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   Some IMAP servers have limits for message upload size, and those
   limits are not published to the email client.  When the email client
   APPENDs a message with huge attachments, using non-synchronizing
   literals, the APPEND fails because of the upload limit, but the
   client has already sent the message data anyway.  This results in
   unnecessary resource usage.  Especially in the mobile device
   environment, appending message with huge attachments consumes device
   resources like device battery power and mobile data.

   The IMAP APPENDLIMIT extension provides an ability to advertise a
   maximum upload size allowed by the IMAP server, so that the email
   client knows the size limitation beforehand.  By implementing this
   extension, IMAP server-side processing of huge attachments above the
   maximum upload size can be avoided.

1.1.  Conventions and Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

   In examples, "C:" and "S:" indicate lines sent by the client and
   server respectively.  If a single "C:" or "S:" label applies to
   multiple lines, then the line breaks between those lines are for
   editorial clarity only and are not part of the actual protocol
   exchange.

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2.  APPENDLIMIT Extension

   An IMAP server that supports the APPENDLIMIT extension advertises
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