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IMAP4 Binary Content Extension (RFC3516)

IP.com Disclosure Number: IPCOM000012212D
Original Publication Date: 2003-Apr-01
Included in the Prior Art Database: 2003-Apr-17
Document File: 9 page(s) / 15K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

L. Nerenberg: AUTHOR

Abstract

This memo defines the Binary extension to the Internet Message Access Protocol (IMAP4). It provides a mechanism for IMAP4 clients and servers to exchange message body data without using a MIME content- transfer-encoding.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 19% of the total text.

Network Working Group                                       L. Nerenberg

Request for Comments: 3516                               Orthanc Systems

Category: Standards Track                                     April 2003

                     IMAP4 Binary Content Extension

Status of this Memo

   This document specifies an Internet standards track protocol for the

   Internet community, and requests discussion and suggestions for

   improvements.  Please refer to the current edition of the "Internet

   Official Protocol Standards" (STD 1) for the standardization state

   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

Abstract

   This memo defines the Binary extension to the Internet Message Access

   Protocol (IMAP4).  It provides a mechanism for IMAP4 clients and

   servers to exchange message body data without using a MIME content-

   transfer-encoding.

1.   Conventions Used in this Document

   The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY"

   in this document are to be interpreted as described in [KEYWORD].

   The abbreviation "CTE" means content-transfer-encoding.

2.   Introduction

   The MIME extensions to Internet messaging allow for the transmission

   of non-textual (binary) message content [MIME-IMB].  Since the

   traditional transports for messaging are not always capable of

   passing binary data transparently, MIME provides encoding schemes

   that allow binary content to be transmitted over transports that are

   not otherwise able to do so.

   The overhead of MIME-encoding this content can be considerable in

   some contexts (e.g., slow radio links, streaming multimedia).

   Reducing the overhead associated with CTE schemes such as base64

Nerenberg                   Standards Track                     [Page 1]

RFC 3516             IMAP4 Binary Content Extension           April 2003

   can give a noticeable reduction in resource consumption.  The Binary

   extension lets the server perform CTE decoding prior to transmitting

   message data to the client.

3.  Content-Transfer-Encoding Considerations

   Every IMAP4 body section has a MIME content-transfer-encoding.

   (Those without an explicit Content-Transfer-Encoding header are

   implicitly labeled as "7bit" content.)  In the terminology of [MIME-

   IMB], the CTE specifies both a decoding algorithm and the domain of

   the decoded data.  In this memo, "decoding" refers to the CTE

   decoding step described in [MIME-IMB].

   Certain CTEs use an identity encoding transformation.  For these CTEs

   there is no decoding required, however the domain of the underlying

   data may not be expressible in the IMAP4 protocol (e.g., MIME

   "binary" conten...