IMAP4 Non-synchronizing Literals
RFC 7888

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Internet Engineering Task Force (IETF)                  A. Melnikov, Ed.
Request for Comments: 7888                                     Isode Ltd
Obsoletes: 2088                                                 May 2016
Category: Standards Track
ISSN: 2070-1721

                    IMAP4 Non-synchronizing Literals

Abstract

   The Internet Message Access Protocol (RFC 3501) contains the
   "literal" syntactic construct for communicating strings.  When
   sending a literal from client to server, IMAP requires the client to
   wait for the server to send a command continuation request between
   sending the octet count and the string data.  This document specifies
   an alternate form of literal that does not require this network round
   trip.

   This document specifies 2 IMAP extensions: LITERAL+ and LITERAL-.
   LITERAL+ allows the alternate form of literals in all IMAP commands.
   LITERAL- is the same as LITERAL+, but it disallows the alternate form
   of literals unless they are 4096 bytes or less.

   This document obsoletes RFC 2088.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7888.

Melnikov                     Standards Track                    [Page 1]
RFC 7888            IMAP4 Non-synchronizing Literals            May 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
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   publication of this document.  Please review these documents
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   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Conventions . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Specification . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Considerations on When to Use and Not to Use Synchronizing
       Literals  . . . . . . . . . . . . . . . . . . . . . . . . . .   5
   5.  LITERAL- Capability . . . . . . . . . . . . . . . . . . . . .   5
   6.  Interaction with BINARY Extension . . . . . . . . . . . . . .   6
   7.  Interaction with MULTIAPPEND Extension  . . . . . . . . . . .   6
   8.  Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . .   6
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     11.1.  Normative References . . . . . . . . . . . . . . . . . .   7
     11.2.  Informative References . . . . . . . . . . . . . . . . .   8
   Appendix A.  Changes since RFC 2088 . . . . . . . . . . . . . . .   9
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   9
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   9

Melnikov                     Standards Track                    [Page 2]
RFC 7888            IMAP4 Non-synchronizing Literals            May 2016

1.  Introduction

   The Internet Message Access Protocol [RFC3501] contains the "literal"
   syntactic construct for communicating strings.  When sending a
   literal from client to server, IMAP requires the client to wait for
   the server to send a command continuation request between sending the
   octet count and the string data.  This document specifies an
   alternate form of literal that does not require this network round