[Docs] [txt|pdf] [Tracker] [WG] [Email] [Nits]

Versions: 00 01 02 03 04 05 06 07 08 RFC 4978

                            <COMPRESSION>               February 2006


Lemonade
Internet Draft: LZIP                                         S. H. Maes
Document: draft-ietf-lemonade-compress-00                   R. Cromwell
                                                              (Editors)




Expires: August 2006                                      February 2006


                               COMPRESSION
Status of this Memo

   By submitting this Internet-Draft, each author represents that any
   applicable patent or other IPR claims of which he or she is aware
   have been or will be disclosed, and any of which he or she becomes
   aware will be disclosed, in accordance with Section 6 of BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   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."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

Copyright Notice

   Copyright (C) The Internet Society (2006).

Abstract

   Lemonade investigates adding mobile optimizations for the next
   version of the Lemonade Profile. LZIP addresses this task and
   provides an extension to allow compression of the exchanged text and
   binary literals, typically message body parts.

Conventions used in this document




Maes                    Expires – August 2006                [Page 1]

                            <COMPRESSION>               February 2006


   In examples, "C:" and "S:" indicate lines sent by the client and
   server respectively.

   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].

   An implementation is not compliant if it fails to satisfy one or more
   of the MUST or REQUIRED level requirements for the protocol(s) it
   implements. An implementation that satisfies all the MUST or REQUIRED
   level and all the SHOULD level requirements for a protocol is said to
   be "unconditionally compliant" to that protocol; one that satisfies
   all the MUST level requirements but not all the SHOULD level
   requirements is said to be "conditionally compliant."  When
   describing the general syntax, some definitions are omitted as they
   are defined in [RFC3501].


Table of Contents

   Status of this Memo ........................................ 1
   Copyright Notice............................................ 1
   Abstract.................................................... 1
   Conventions used in this document........................... 1
   Table of Contents........................................... 2
   1. Introduction............................................. 2
   2. The CAPABILITY Command................................... 3
   3. LZIP Commands............................................ 3
   4. LZIP Response............................................ 3
   5. Formal Syntax............................................ 4
   Security Considerations..................................... 4
   References.................................................. 4
   Future Work................................................. 5
   Version History............................................. 5
   Acknowledgments............................................. 5
   Authors Addresses........................................... 6
   Intellectual Property Statement............................. 6
   Disclaimer of Validity...................................... 7
   Copyright Statement ........................................ 7


1.
   Introduction

   LZIP provides an extension to allow compression of text and binary
   literals.

   While it could be argued that transport could provide generic
   compression of the data (e.g. TLS with NULL Cipher), application
   level compression presents the advantage to be better tunable to the


Maes                    Expires – August 2006                [Page 2]

                            <COMPRESSION>               February 2006


   type of data being requested, for example, to avoid compression of
   already compressed data.

   Compression performances depend on the actual types of e-mail that
   are received. They change between text bodies and different types of
   attachments.  In general, LZIP presents a worthwhile gain over
   uncompressed or network compressed only approached at very little
   extra cost for the implementer.

   Bandwidth optimization are important features required in particular
   to support mobile email use cases [MEMAIL][OMA-ME-RD]


2.
  The CAPABILITY Command

   Servers which support LZIP MUST return ‘LZIP’ in the response list to
   a capability command.

   Example: A LEMONADE server that implements LZIP.
      C: a001 CAPABILITY
      S: * CAPABILITY IMAP4rev1 AUTH=LOGIN IDLE LZIP
      S: a001 OK CAPABILITY completed

3.
  LZIP Commands

   The LZIP command is an extension of [RFC3516] IMAP BINARY, which
   introduces three new commands “LZIP”, “LZIP.PEEK”, “LZIP.SIZE” that
   parallel the syntax and semantics of “BINARY”, “BINARY.PEEK”, and
   “BINARY.SIZE” in [RFC3516]. In general, LZIP inherits all of the
   requirements and semantics of [RFC3516]’s “BINARY” and “BINARY.PEEK”,
   except that the content transfer encoding being requested is
   understood to be the result of what would be returned from BINARY
   decoding, followed by the application of the DEFLATE algorithm.


   Example: Zipping a body part fetch
      C: A1 FETCH 123 LZIP.PEEK[1.2]
      S: * LZIP[1.2]~{1234}
      S: ….binary decoded and deflated data….
      S: A1 OK FETCH completed

      As mentioned in RFC3516, LZIP.SIZE is a potentially expensive
   operation, as in LZIP, so clients should be aware that making
   successive requests for the same part may be expensive.

4.
  LZIP Response

   As the result of processing an LZIP command, two new responses, LZIP
   and LZIP.SIZE which parallel that responses of [RFC3516] are


Maes                    Expires – August 2006                [Page 3]

                            <COMPRESSION>               February 2006


   introduced. They are identical in syntax and semantics of the BINARY
   responses in [RFC3516] in everyway, except that the resulting binary
   literal is understood to be in DEFLATE format.


5.
  Formal Syntax

   The following syntax specification uses the Augmented Backus-Naur
   Form (ABNF) notation.  Elements not defined here can be found in
   the formal syntax of the [ABNF], [RFC3501], and [ABNFEXTEND].

   The create ABNF grammar in [RFC3501] is hereby modified to the
   grammar defined in [ABNFEXTEND]


      fetch-att      =/  "LZIP" [".PEEK"] section-binary [partial]
                         / "LZIP.SIZE" section-binary

      msg-att-static =/  "LZIP" section-binary SP (nstring / literal8)
                         / "LZIP.SIZE" section-binary SP number

Security Considerations

   LZIP does not introduce additional security consideration with
   respect to IMAPv4Rev1.


References

   [LEMONADEPROFILE] Maes, S.H. and Melnikov A., "Lemonade Profile",
      draft-ietf-lemonade-profile-XX.txt, (work in progress).

   [MEMAIL] Maes, S.H., “Lemonade and Mobile e-mail", draft-maes-
      lemonade-mobile-email-xx.txt, (work in progress).

   [OMA-ME-RD] Open Mobile Alliance Mobile Email Requirement Document,
      (Work in progress).  http://www.openmobilealliance.org/

   [P-IMAP] Maes, S.H., Lima R., Kuang, C., Cromwell, R., Ha, V. and
      Chiu, E., Day, J., Ahad R., Jeong W-H., Rosell G., Sini, J., Sohn
      S-M., Xiaohui F. and Lijun Z., "Push Extensions to the IMAP
      Protocol (P-IMAP)", draft-maes-lemonade-p-imap-xx.txt, (work in
      progress).

   [RFC1951] Deutsch, P. “DEFLATE Compressed Data Format Specification
      version 1.3”, RFC1951, May 1996.
      http://www.ietf.org/rfc/rfc1951




Maes                    Expires – August 2006                [Page 4]

                            <COMPRESSION>               February 2006


   [RFC2119] Brader, S.  "Keywords for use in RFCs to Indicate
      Requirement Levels", RFC 2119, March 1997.
      http://www.ietf.org/rfc/rfc2119

   [RFC3501] Crispin, M. "IMAP4, Internet Message Access Protocol
      Version 4 rev1", RFC 3501, March 2003.
      http://www.ietf.org/rfc/rfc3501

   [RFC3516] Nerenberg, L. “IMAP4 Binary Content Extension”, RFC3516,
      April 2003.
      http://www.ietf.org/rfc/rfc3516

Future Work

   Should a new “compressed literal” be considered paralleling the
   binary literal8 syntax? For example, %~{nz-number}? Potential
   applications could be its usage in APPEND/CATENATE.

Version History

   Release 00 of draft-maes-lemonadel-lzip
      Initial release published in June 2005
   Release 01 of draft-maes-lemonadel-lzip
         Shortened list of editors. Authors pushed to acknowledgements
            Section 2: Addition of exact compression algorithm
   references
            Section 4:
               Addition of exact compression algorithm references
               Considerations on command compression added
               Correction and updates of examples
            References:
               Additional references on compression algorithms and IMAP4
            Binary.
      Release 02 of draft-maes-lemonadel-lzip
         Reworked to model IMAP BINARY
      Release 00 of IETF draft
            Re-cast LZIP to focus on compression of text and binary
   literals.

Acknowledgments

   The authors want to thank all who have contributed key insight and
   extensively reviewed and discussed the concepts of LPSEARCH and its
   early introduction P-IMAP [P-IMAP]. In particular, this includes the
   authors of the P-IMAP draft: Rafiul Ahad – Oracle Corporation, Eugene
   Chiu – Oracle Corporation, Ray Cromwell – Oracle Corporation, Jia-der
   Day – Oracle Corporation, Vi Ha – Oracle Corporation, Wook-Hyun Jeong
   – Samsung Electronics Co. LTF, Chang Kuang – Oracle Corporation,
   Rodrigo Lima – Oracle Corporation, Stephane H. Maes – Oracle


Maes                    Expires – August 2006                [Page 5]

                            <COMPRESSION>               February 2006


   Corporation, Gustaf Rosell - Sony Ericsson, Jean Sini – Symbol
   Technologies, Sung-Mu Son – LG Electronics, Fan Xiaohui - CHINA
   MOBILE COMMUNICATIONS CORPORATION (CMCC), Zhao Lijun - CHINA MOBILE
   COMMUNICATIONS CORPORATION (CMCC). We also want to give a special
   thanks to A. Melnikov for his review and suggestions.


Authors Addresses

   Stephane H. Maes
   Oracle Corporation
   500 Oracle Parkway
   M/S 4op634
   Redwood Shores, CA 94065
   USA
   Phone: +1-650-607-6296
   Email: stephane.maes@oracle.com


   Ray Cromwell
   Oracle Corporation
   500 Oracle Parkway
   Redwood Shores, CA 94065
   USA

   Anil Srivastava
   Sun Microsystems
   4150 Network Circle SCA15/201
   Santa Clara, CA 94065
   anil.srivastava@sun.com


Intellectual Property Statement

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; nor does it represent that it has
   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 7878 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.


Maes                    Expires – August 2006                [Page 6]

                            <COMPRESSION>               February 2006



   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at ietf-
   ipr@ietf.org.

Disclaimer of Validity
   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
   ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
   INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
   INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Copyright Statement

   Copyright (C) The Internet Society (2006).  This document is subject
   to the rights, licenses and restrictions contained in BCP 78, and
   except as set forth therein, the authors retain all their rights.

Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.

























Maes                    Expires – August 2006                [Page 7]


Html markup produced by rfcmarkup 1.109, available from https://tools.ietf.org/tools/rfcmarkup/