[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01 02 03 04 05 06 07 08 09 10 11 12 RFC 5550

LEMONADE Working Group                                      S. Maes, Ed.
Internet-Draft                                                    Oracle
Expires: December 31, 2006                              A. Melnikov, Ed.
                                                           Isode Limited
                                                        D. Cridland, Ed.
                                                   Inventure Systems Ltd
                                                           June 29, 2006


                          LEMONADE profile bis
                 draft-ietf-lemonade-profile-bis-03.txt

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.

   This Internet-Draft will expire on December 31, 2006.

Copyright Notice

   Copyright (C) The Internet Society (2006).

Abstract

   This document describes the LEMONADE profile.  It contains pointers
   to or descriptions of all the features that are normatively part of
   this version of the LEMONADE profile.

   This document describes a profile (a set of required extensions,



Maes, et al.            Expires December 31, 2006               [Page 1]

Internet-Draft            LEMONADE profile bis                 June 2006


   restrictions and usage modes) of the IMAP and mail submission
   protocols.  This profile allows clients (especially those that are
   constrained in memory, bandwidth, processing power, or other areas)
   to efficiently use IMAP and Submission to access and submit mail.
   This includes the ability to forward received mail without needing to
   download and upload the mail, to optimize submission and to
   efficiently resynchronize in case of loss of connectivity with the
   server.

   The Lemonade profile relies upon extensions to IMAP and Mail
   Submission protocols; specifically URLAUTH and CATENATE IMAP protocol
   extensions and BURL extension to the SUBMIT protocol.


Table of Contents

   1.  Conventions used in this document  . . . . . . . . . . . . . .  4
   2.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Forward without download . . . . . . . . . . . . . . . . . . .  5
     3.1.  Motivations  . . . . . . . . . . . . . . . . . . . . . . .  5
     3.2.  Message Sending Overview . . . . . . . . . . . . . . . . .  5
     3.3.  Traditional Strategy . . . . . . . . . . . . . . . . . . .  6
     3.4.  Step by step description . . . . . . . . . . . . . . . . .  7
       3.4.1.  Message assembly using IMAP CATENATE extension . . . .  7
       3.4.2.  Message assembly using SMTP CHUNKING and BURL
               extensions . . . . . . . . . . . . . . . . . . . . . . 12
     3.5.  Normative statements related to forward without
           download . . . . . . . . . . . . . . . . . . . . . . . . . 16
     3.6.  Security Considerations for pawn-tickets.  . . . . . . . . 16
     3.7.  Copies of Sent messages: The fcc problem . . . . . . . . . 17
     3.8.  Registration of $Forwarded IMAP keyword  . . . . . . . . . 17
   4.  Message Submission . . . . . . . . . . . . . . . . . . . . . . 17
     4.1.  Pipelining . . . . . . . . . . . . . . . . . . . . . . . . 18
     4.2.  DSN Support  . . . . . . . . . . . . . . . . . . . . . . . 18
     4.3.  Message size declaration . . . . . . . . . . . . . . . . . 18
     4.4.  Enhanced status code Support . . . . . . . . . . . . . . . 18
     4.5.  TLS  . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
   5.  Message Store  . . . . . . . . . . . . . . . . . . . . . . . . 18
     5.1.  Quick resynchronization  . . . . . . . . . . . . . . . . . 19
     5.2.  Message part handling  . . . . . . . . . . . . . . . . . . 19
     5.3.  Compression  . . . . . . . . . . . . . . . . . . . . . . . 19
     5.4.  Out of band notifications  . . . . . . . . . . . . . . . . 19
     5.5.  Virtual Mailboxes  . . . . . . . . . . . . . . . . . . . . 20
     5.6.  Additional IMAP extensions . . . . . . . . . . . . . . . . 20
   6.  Summary of the required IMAP and SMTP extensions . . . . . . . 21
   7.  OMA MEM Requirement document . . . . . . . . . . . . . . . . . 21
     7.1.  OMA MEM Architecture . . . . . . . . . . . . . . . . . . . 22
     7.2.  OMA MEM Deployment Issues  . . . . . . . . . . . . . . . . 22



Maes, et al.            Expires December 31, 2006               [Page 2]

Internet-Draft            LEMONADE profile bis                 June 2006


     7.3.  OMA MEM proxy  . . . . . . . . . . . . . . . . . . . . . . 22
     7.4.  IETF LEMONADE Architecture . . . . . . . . . . . . . . . . 22
     7.5.  LEMONADE profile logical architecture  . . . . . . . . . . 24
       7.5.1.  Relationship between the OMA MEM and LEMONADE
               logical architectures  . . . . . . . . . . . . . . . . 24
       7.5.2.  LEMONADE realization of OMA MEM with non-LEMONADE
               compliant servers  . . . . . . . . . . . . . . . . . . 26
     7.6.  Filters and server to client notifications and LEMONADE  . 27
     7.7.  LEMONADE Profile features  . . . . . . . . . . . . . . . . 29
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 30
     8.1.  Confidentiality Protection of Submitted Messages . . . . . 30
     8.2.  TLS  . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
     8.3.  Additional extensions and deployment models  . . . . . . . 31
   9.  IANA considerations  . . . . . . . . . . . . . . . . . . . . . 31
   10. Future work  . . . . . . . . . . . . . . . . . . . . . . . . . 31
   11. Version history  . . . . . . . . . . . . . . . . . . . . . . . 31
   12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 32
   Appendix A.  Streaming attachments . . . . . . . . . . . . . . . . 32
   13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 34
     13.1. Normative References . . . . . . . . . . . . . . . . . . . 34
     13.2. Informative References . . . . . . . . . . . . . . . . . . 37
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 38
   Intellectual Property and Copyright Statements . . . . . . . . . . 39




























Maes, et al.            Expires December 31, 2006               [Page 3]

Internet-Draft            LEMONADE profile bis                 June 2006


1.  Conventions used in this document

   In examples, "M:", "I:" and "S:" indicate lines sent by the client
   messaging user agent, IMAP e-mail server and SMTP submit 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].

   Other capitalised words are typically names of extensions or commands
   - these are uppercased for clarity only, and are case-insensitive.

   All examples in this document are optimized for Lemonade use and
   might not represent examples of proper protocol usage for a general
   use Submit/IMAP client.  In particular examples assume that Lemonade
   Submit and IMAP servers support all Lemonade extensions described in
   this document, so they do not demonstrate fallbacks in the absence of
   an extension.


2.  Introduction

   LEMONADE provides enhancements to Internet email to support diverse
   service environments.

   This document describes the LEMONADE profile that includes:
   o  "Forward without download" that describes exchanges between
      Lemonade clients and servers to allow to submit new email messages
      incorporating content which resides on locations external to the
      client.
   o  Quick mailbox resynchronization using [RFC4551].
   o  Several IMAP and SMTP extensions that allow saving bandwidth
      and/or number of round trips required to send/receive data.
   o  Extensions to provide support to realizations of OMA mobile email
      enabler (MEM) [MEM-req] [MEM-arch] using Internet Mail protocols
      defined by the IETF.

   <<Editor's note: This document contains the current view of the work.
   It refers to stable specifications and work in progress.  As the work
   progress, it is expected that this document will evolve and be
   updated accordingly.  As a result some of the statements about some
   specification may not yet be supported by the references.  When that
   is the case, these specifications are expected to be be updated.>>

   Also, it is to be noted that this document solely describes
   normatively the LEMONADE profile.  It discusses LEMONADE
   understanding of the work in progress at OMA MEM ([MEM-req] and [MEM-



Maes, et al.            Expires December 31, 2006               [Page 4]

Internet-Draft            LEMONADE profile bis                 June 2006


   arch] but does not provide a normative reading of these documents.
   Readers MUST refer to the Open Mobile Alliance web site for normative
   references on the Mobile Email Enabler (OMA MEM).  The LEMONADE
   working group believes that the LEMONADE profile can be used as basis
   for an OMA technical specification of a realization based on LEMONADE
   of the OMA MEM enabler.


3.  Forward without download

3.1.  Motivations

   The advent of client/server email using the [RFC3501], [RFC2821] and
   [RFC4409] protocols has changed what formerly were local disk
   operations to become repetitive network data transmissions.

   Lemonade "forward without download" makes use of the [RFC4468] SUBMIT
   extension to enable access to external sources during the submission
   of a message.  In combination with the IMAP [RFC4467] extension,
   inclusion of message parts or even entire messages from the IMAP mail
   store is possible with a minimal trust relationship between the IMAP
   and SMTP SUBMIT servers.

   Lemonade "forward without download" has the advantage of maintaining
   one submission protocol, and thus avoids the risk of having multiple
   parallel and possibly divergent mechanisms for submission.  The
   client can use Submit/SMTP [RFC4409] extensions without these being
   added to IMAP.  Furthermore, by keeping the details of message
   submission in the SMTP SUBMIT server, Lemonade "forward without
   download" can work with other message retrieval protocols such as
   POP, NNTP, or whatever else may be designed in the future.

3.2.  Message Sending Overview

   The act of sending an email message can be thought of as involving
   multiple steps: initiation of a new draft, draft editing, message
   assembly, and message submission.

   Initiation of a new draft and draft editing takes place in the MUA.
   Frequently, users choose to save more complex messages on an
   [RFC3501] server (via the APPEND command with the \Draft flag) for
   later recall by the MUA and resumption of the editing process.

   Message assembly is the process of producing a complete message from
   the final revision of the draft and external sources.  At assembly
   time, external data is retrieved and inserted in the message.

   Message submission is the process of inserting the assembled message



Maes, et al.            Expires December 31, 2006               [Page 5]

Internet-Draft            LEMONADE profile bis                 June 2006


   into the [RFC2821] infrastructure, typically using the [RFC4409]
   protocol.

3.3.  Traditional Strategy

   Traditionally, messages are initiated, edited, and assembled entirely
   within an MUA, although drafts may be saved to an [RFC3501] server
   and later retrieved from the server.  The completed text is then
   transmitted to an MSA for delivery.

   There is often no clear boundary between the editing and assembly
   process.  If a message is forwarded, its content is often retrieved
   immediately and inserted into the message text.  Similarly, when
   external content is inserted or attached, the content is usually
   retrieved immediately and made part of the draft.

   As a consequence, each save of a draft and subsequent retrieve of the
   draft transmits that entire (possibly large) content, as does message
   submission.

   In the past, this was not much of a problem, because drafts, external
   data, and the message submission mechanism were typically located on
   the same system as the MUA.  The most common problem was running out
   of disk quota.



























Maes, et al.            Expires December 31, 2006               [Page 6]

Internet-Draft            LEMONADE profile bis                 June 2006


3.4.  Step by step description

   The model distinguishes between a Messaging User Agent (MUA), an
   IMAPv4Rev1 Server ([RFC3501]) and a SMTP submit server ([RFC4409]),
   as illustrated in Figure 1.

         +--------------------+               +--------------+
         |                    | <------------ |              |
         |     MUA (M)        |               | IMAPv4Rev1   |
         |                    |               |  Server      |
         |                    | ------------> | (Server I)   |
         +--------------------+               +--------------+
                ^    |                              ^     |
                |    |                              |     |
                |    |                              |     |
                |    |                              |     |
                |    |                              |     |
                |    |                              |     |
                |    |                              |     v
                |    |                        +--------------+
                |    |----------------------> |   SMTP       |
                |                             |   Submit     |
                |-----------------------------|   Server     |
                                              |  (Server S)  |
                                              +--------------+

   Figure 1: Lemonade "forward without download"

   Lemonade "forward without download" allows a Messaging User Agent to
   compose and forward an e-mail combining fragments that are located in
   an IMAP server, without having to download these fragments to the
   client.

   There are two ways to perform "forward without download" based on
   where the message assembly takes place.  The first uses extended
   APPEND command [RFC4469] to edit a draft message in the message store
   and cause the message assembly on the IMAP server.  The second uses a
   succession of BURL and BDAT commands to submit and assemble through
   concatenation, message data from the client and external data fetched
   from the provided URL.  The two subsequent sections provide step-by-
   step instructions on how "forward without download" is achieved.

3.4.1.  Message assembly using IMAP CATENATE extension

   In the BURL [RFC4468]/CATENATE [RFC4469] variant of the Lemonade
   "forward without download" strategy, messages are initially composed
   and edited within an MUA.  The [RFC4469] extension to [RFC3501] is
   then used to create the messages on the IMAP server by transmitting



Maes, et al.            Expires December 31, 2006               [Page 7]

Internet-Draft            LEMONADE profile bis                 June 2006


   new text and assembling them.  The UIDPLUS [RFC4315] IMAP extension
   is used by the client in order to learn the UID of the created
   messages.  Finally a [RFC4467] format URL is given to a [RFC4409]
   server for submission using the BUTL [RFC4468] extension.

   The flow involved to support such a use case consists of:

   M: {to I -- Optional} The client connects to the IMAP server,
   optionally starts TLS (if data confidentiality is required),
   authenticates, opens a mailbox ("INBOX" in the example below) and
   fetches body structures (See [RFC3501]).

   Example:

            M: A0051 UID FETCH 25627 (UID BODYSTRUCTURE)
            I: * 161 FETCH (UID 25627 BODYSTRUCTURE (("TEXT" "PLAIN"
                ("CHARSET" "US-ASCII") NIL NIL "7BIT" 1152 23)(
                "TEXT" "PLAIN" ("CHARSET" "US-ASCII" "NAME"
                "trip.txt")
                "<960723163407.20117h@washington.example.com>"
                "Your trip details" "BASE64" 4554 73) "MIXED"))
            I: A0051 OK completed

   M: {to I} The client invokes CATENATE (See [RFC4469] for details of
   the semantics and steps) -- this allows the MUA to create messages on
   the IMAP server using new data combined with one or more message
   parts already present on the IMAP server.

   Note that the example for this step doesn't use the LITERAL+
   [RFC2088] extension.  Without LITERAL+ the new message is constructed
   using 3 round-trips.  If LITERAL+ is used, the new message can be
   constructed using one round-trip.



















Maes, et al.            Expires December 31, 2006               [Page 8]

Internet-Draft            LEMONADE profile bis                 June 2006


         M: A0052 APPEND Sent FLAGS (\Draft \Seen $MDNSent)
             CATENATE (TEXT {475}
         I: + Ready for literal data
         M: Message-ID: <419399E1.6000505@caernarfon.example.org>
         M: Date: Thu, 12 Nov 2004 16:57:05 +0000
         M: From: Bob Ar <bar@example.org>
         M: MIME-Version: 1.0
         M: To: foo@example.net
         M: Subject: About our holiday trip
         M: Content-Type: multipart/mixed;
         M:     boundary="------------030308070208000400050907"
         M:
         M: --------------030308070208000400050907
         M: Content-Type: text/plain; format=flowed
         M:
         M: Our travel agent has sent the updated schedule.
         M:
         M: Cheers,
         M: Bob
         M: --------------030308070208000400050907
         M:  URL "/INBOX;UIDVALIDITY=385759045/;
            UID=25627/;Section=2.MIME" URL "/INBOX;
            UIDVALIDITY=385759045/;UID=25627/;Section=2" TEXT {44}
         I: + Ready for literal data
         M:
         M: --------------030308070208000400050907--
         M: )
         I: A0052 OK [APPENDUID 387899045 45] CATENATE Completed

   M: {to I} The client uses GENURLAUTH command to request a URLAUTH URL
   (See [RFC4467]).
   I: {to M} The IMAP server returns a URLAUTH URL suitable for later
   retrieval with URLFETCH (See [RFC4467] for details of the semantics
   and steps).

         M: A0054 GENURLAUTH "imap://bob.ar@example.org/Sent;
            UIDVALIDITY=387899045/;uid=45;expire=2005-10-
            28T23:59:59Z;urlauth=submit+bob.ar" INTERNAL
         I: * GENURLAUTH "imap://bob.ar@example.org/Sent;
            UIDVALIDITY=387899045/;uid=45;expire=
            2005-10-28T23:59:59Z;urlauth=submit+bob.ar:
            internal:91354a473744909de610943775f92038"
         I: A0054 OK GENURLAUTH completed

   M: {to S} The client connects to the mail submission server and
   starts a new mail transaction.  It uses BURL to let the SMTP submit
   server fetch the content of the message from the IMAP server (See
   [RFC4468] for details of the semantics and steps -- this allows the



Maes, et al.            Expires December 31, 2006               [Page 9]

Internet-Draft            LEMONADE profile bis                 June 2006


   MUA to authorize the SMTP submit server to access the message
   composed as a result of the CATENATE step).  Note that the second
   EHLO command is required after a successful STARTTLS command.  Also
   note that there might be a third required EHLO command if the second
   EHLO response doesn't list any BURL options.  Section 3.4.2
   demonstrates this.

         S: 220 owlry.example.org ESMTP
         M: EHLO potter.example.org
         S: 250-owlry.example.com
         S: 250-8BITMIME
         S: 250-BINARYMIME
         S: 250-PIPELINING
         S: 250-BURL imap
         S: 250-CHUNKING
         S: 250-AUTH PLAIN
         S: 250-DSN
         S: 250-SIZE 10240000
         S: 250-STARTTLS
         S: 250 ENHANCEDSTATUSCODES
         M: STARTTLS
         S: 220 Ready to start TLS
         ...TLS negotiation, subsequent data is encrypted...
         M: EHLO potter.example.org
         S: 250-owlry.example.com
         S: 250-8BITMIME
         S: 250-BINARYMIME
         S: 250-PIPELINING
         S: 250-BURL imap
         S: 250-CHUNKING
         S: 250-AUTH PLAIN
         S: 250-DSN
         S: 250-SIZE 10240000
         S: 250 ENHANCEDSTATUSCODES
         M: AUTH PLAIN aGFycnkAaGFycnkAYWNjaW8=
         S: 235 2.7.0 PLAIN authentication successful.
         M: MAIL FROM:<bob.ar@example.org>
         S: 250 2.5.0 Address Ok.
         M: RCPT TO:<foo@example.net>
         S: 250 2.1.5 foo@example.net OK.
         M: BURL imap://bob.ar@example.org/Sent;UIDVALIDITY=387899045/;
            uid=45/;urlauth=submit+bar:internal:
            91354a473744909de610943775f92038 LAST

   S: {to I} The mail submission server uses URLFETCH to fetch the
   message to be sent (See [RFC4467] for details of the semantics and
   steps.  The so-called "pawn-ticket" authorization mechanism uses a
   URI which contains its own authorization credentials.).



Maes, et al.            Expires December 31, 2006              [Page 10]

Internet-Draft            LEMONADE profile bis                 June 2006


   I: {to S} Provides the message composed as a result of the CATENATE
   step).

   Mail submission server opens IMAP connection to the IMAP server:

         I: * OK [CAPABILITY IMAP4REV1 STARTTLS NAMESPACE LITERAL+
             CATENATE URLAUTH UIDPLUS CONDSTORE IDLE] imap.example.com
             IMAP server ready
         S: a000 STARTTLS
         I: a000 Start TLS negotiation now
         ...TLS negotiation, if successful - subsequent data
            is encrypted...
         S: a001 LOGIN submitserver secret
         I: a001 OK submitserver logged in
         S: a002 URLFETCH "imap://bob.ar@example.org/Sent;
            UIDVALIDITY=387899045/;uid=45/;urlauth=submit+bob.ar:
            internal:91354a473744909de610943775f92038"
         I: * URLFETCH "imap://bob.ar@example.org/Sent;
            UIDVALIDITY=387899045/;uid=45/;urlauth=submit+bob.ar:
            internal:91354a473744909de610943775f92038" {15065}
         ...message body follows...
         S: a002 OK URLFETCH completed
         I: a003 LOGOUT
         S: * BYE See you later
         S: a003 OK Logout successful

   Note that if the IMAP server doesn't send CAPABILITY response code in
   the greeting, the mail submission server must issue the CAPABILITY
   command to learn about supported IMAP extensions as described in
   [RFC3501].

   Also, if data confidentiality is not required the mail submission
   server may omit the STARTTLS command before issuing the LOGIN
   command.

   S: {to M} Submission server assembles the complete message and if the
   assembly succeeds it returns OK to the MUA:

         S: 250 2.5.0 Ok.

   M: {to I} The client marks the message containing the forwarded
   attachment on the IMAP server.

         M: A0053 UID STORE 25627 +FLAGS.SILENT ($Forwarded)
         I: * 215 FETCH (UID 25627 MODSEQ (12121231000))
         I: A0053 OK STORE completed

   Note: the UID STORE command shown above will only work if the marked



Maes, et al.            Expires December 31, 2006              [Page 11]

Internet-Draft            LEMONADE profile bis                 June 2006


   message is in the currently selected mailbox; otherwise, it requires
   a SELECT.  This command can be omitted, as it simply changes non-
   operational metadata not essential to client operations or
   interoperability.  The untagged FETCH response is due to [RFC4551].
   The $Forwarded IMAP keyword is described in Section 3.8.

3.4.2.  Message assembly using SMTP CHUNKING and BURL extensions

   In the [RFC4468]/[RFC3030] variant of the Lemonade "forward without
   download" strategy, messages are initially composed and edited within
   an MUA.  During submission [RFC4409], BURL [RFC4468] and BDAT
   [RFC3030] commands are used to create the messages from multiple
   parts.  New body parts are supplied using BDAT commands, while
   existing body parts are referenced using [RFC4467] format URLs in
   BURL commands.

   The flow involved to support such a use case consists of:
   M: {to I -- Optional} The client connects to the IMAP server,
   optionally starts TLS (if data confidentiality is required),
   authenticates, opens a mailbox ("INBOX" in the example below) and
   fetches body structures (See [RFC3501]).

   Example:

            M: A0051 UID FETCH 25627 (UID BODYSTRUCTURE)
            I: * 161 FETCH (UID 25627 BODYSTRUCTURE (("TEXT" "PLAIN"
               ("CHARSET" "US-ASCII") NIL NIL "7BIT" 1152 23)(
               "TEXT" "PLAIN" ("CHARSET" "US-ASCII" "NAME"
               "trip.txt")
               "<960723163407.20117h@washington.example.com>"
               "Your trip details" "BASE64" 4554 73) "MIXED"))
            I: A0051 OK completed

   M: {to I} The client uses GENURLAUTH command to request URLAUTH URLs
   (See [RFC4467]) referencing pieces of the message to be assembled.
   I: {to M} The IMAP server returns URLAUTH URLs suitable for later
   retrieval with URLFETCH (See [RFC4467] for details of the semantics
   and steps).













Maes, et al.            Expires December 31, 2006              [Page 12]

Internet-Draft            LEMONADE profile bis                 June 2006


         M: A0054 GENURLAUTH "imap://bob.ar@example.org/INBOX;
            UIDVALIDITY=385759045/;UID=25627/;Section=2.MIME;
            expire=2006-10-28T23:59:59Z;urlauth=submit+bob.ar"
            INTERNAL "imap://bob.ar@example.org/INBOX;
            UIDVALIDITY=385759045/;UID=25627/;Section=2;
            expire=2006-10-28T23:59:59Z;urlauth=submit+bob.ar" INTERNAL
         I: * GENURLAUTH "imap://bob.ar@example.org/INBOX;
            UIDVALIDITY=385759045/;UID=25627/;Section=2.MIME;
            expire=2006-10-28T23:59:59Z;urlauth=submit+bob.ar:
            internal:A0DEAD473744909de610943775f9BEEF"
            "imap://bob.ar@example.org/INBOX;
            UIDVALIDITY=385759045/;UID=25627/;Section=2;
            expire=2006-10-28T23:59:59Z;urlauth=submit+bob.ar:
            internal:BEEFA0DEAD473744909de610943775f9"
         I: A0054 OK GENURLAUTH completed

   M: {to S} The client connects to the mail submission server and
   starts a new mail transaction.  It uses BURL to instruct the SMTP
   submit server to fetch from the IMAP server pieces of the message to
   be sent (See [RFC4468] for details of the semantics and steps).

   Note that the second EHLO command is required after a successful
   STARTTLS command.  The third EHLO command is required if and only if
   the second EHLO response doesn't list any BURL options.  See
   Section 3.4.1 for an example of submission where the third EHLO
   command/response is not present.

         S: 220 owlry.example.org ESMTP
         M: EHLO potter.example.org
         S: 250-owlry.example.com
         S: 250-8BITMIME
         S: 250-BINARYMIME
         S: 250-PIPELINING
         S: 250-BURL
         S: 250-CHUNKING
         S: 250-AUTH DIGEST-MD5
         S: 250-DSN
         S: 250-SIZE 10240000
         S: 250-STARTTLS
         S: 250 ENHANCEDSTATUSCODES
         M: STARTTLS
         S: 220 Ready to start TLS
         ...TLS negotiation, subsequent data is encrypted...
         M: EHLO potter.example.org
         S: 250-owlry.example.com
         S: 250-8BITMIME
         S: 250-BINARYMIME
         S: 250-PIPELINING



Maes, et al.            Expires December 31, 2006              [Page 13]

Internet-Draft            LEMONADE profile bis                 June 2006


         S: 250-BURL
         S: 250-CHUNKING
         S: 250-AUTH DIGEST-MD5 CRAM-MD5 PLAIN EXTERNAL
         S: 250-DSN
         S: 250-SIZE 10240000
         S: 250 ENHANCEDSTATUSCODES
         M: AUTH PLAIN aGFycnkAaGFycnkAYWNjaW8=
         S: 235 2.7.0 PLAIN authentication successful.
         M: EHLO potter.example.org
         S: 250-owlry.example.com
         S: 250-8BITMIME
         S: 250-BINARYMIME
         S: 250-PIPELINING
         S: 250-BURL imap imap://imap.example.org
         S: 250-CHUNKING
         S: 250-AUTH DIGEST-MD5 CRAM-MD5 PLAIN EXTERNAL
         S: 250-DSN
         S: 250-SIZE 10240000
         S: 250 ENHANCEDSTATUSCODES
         M: MAIL FROM:<bob.ar@example.org> BODY=BINARY
         S: 250 2.5.0 Address Ok.
         M: RCPT TO:<foo@example.net>
         S: 250 2.1.5 foo@example.net OK.
         M: BDAT 475
         M: Message-ID: <419399E1.6000505@caernarfon.example.org>
         M: Date: Thu, 12 Nov 2004 16:57:05 +0000
         M: From: Bob Ar <bar@example.org>
         M: MIME-Version: 1.0
         M: To: foo@example.net
         M: Subject: About our holiday trip
         M: Content-Type: multipart/mixed;
         M:     boundary="------------030308070208000400050907"
         M:
         M: --------------030308070208000400050907
         M: Content-Type: text/plain; format=flowed
         M:
         M: Our travel agent has sent the updated schedule.
         M:
         M: Cheers,
         M: Bob
         M: --------------030308070208000400050907
         S: 250 2.5.0 OK
         M: BURL imap://bob.ar@example.org/INBOX;
            UIDVALIDITY=385759045/;UID=25627/;Section=2.MIME;
            expire=2006-10-28T23:59:59Z;urlauth=submit+bob.ar:
            internal:A0DEAD473744909de610943775f9BEEF
         S: 250 2.5.0 OK
         M: BURL imap://bob.ar@example.org/INBOX;



Maes, et al.            Expires December 31, 2006              [Page 14]

Internet-Draft            LEMONADE profile bis                 June 2006


            UIDVALIDITY=385759045/;UID=25627/;Section=2;
            expire=2006-10-28T23:59:59Z;urlauth=submit+bob.ar:
            internal:BEEFA0DEAD473744909de610943775f9
         S: 250 2.5.0 OK
         M: BDAT 44 LAST
         M:
         M: --------------030308070208000400050907--

   S: {to I} The mail submission server uses URLFETCH to fetch the
   pieces of the message to be sent (See [RFC4467] for details of the
   semantics and steps.  The so-called "pawn-ticket" authorization
   mechanism uses a URI which contains its own authorization
   credentials.).
   I: {to S} Returns the requested body parts.

   Mail submission server opens IMAP connection to the IMAP server:

         I: * OK [CAPABILITY IMAP4REV1 STARTTLS NAMESPACE LITERAL+
             CATENATE URLAUTH UIDPLUS CONDSTORE IDLE] imap.example.com
             IMAP server ready
         S: a001 LOGIN submitserver secret
         I: a001 OK submitserver logged in
         S: a002 URLFETCH "imap://bob.ar@example.org/INBOX;
            UIDVALIDITY=385759045/;UID=25627/;Section=2.MIME;
            expire=2006-10-28T23:59:59Z;urlauth=submit+bob.ar:
            internal:A0DEAD473744909de610943775f9BEEF" "imap://
            bob.ar@example.org/INBOX;
            UIDVALIDITY=385759045/;UID=25627/;Section=2;
            expire=2006-10-28T23:59:59Z;urlauth=submit+bob.ar:
            internal:BEEFA0DEAD473744909de610943775f9"
         I: * URLFETCH "imap://bob.ar@example.org/INBOX;
            UIDVALIDITY=385759045/;UID=25627/;Section=2.MIME;
            expire=2006-10-28T23:59:59Z;urlauth=submit+bob.ar:
            internal:A0DEAD473744909de610943775f9BEEF" {84}
         ...message section follows...
             "imap://bob.ar@example.org/INBOX;
            UIDVALIDITY=385759045/;UID=25627/;Section=2;
            expire=2006-10-28T23:59:59Z;urlauth=submit+bob.ar:
            internal:BEEFA0DEAD473744909de610943775f9" {15065}
         ...message section follows...
         S: a002 OK URLFETCH completed
         I: a003 LOGOUT
         S: * BYE See you later
         S: a003 OK Logout successful

   Note that if the IMAP server doesn't send CAPABILITY response code in
   the greeting, the mail submission server must issue the CAPABILITY
   command to learn about supported IMAP extensions as described in



Maes, et al.            Expires December 31, 2006              [Page 15]

Internet-Draft            LEMONADE profile bis                 June 2006


   [RFC3501].

   Also, if data confidentiality is required the mail submission server
   should start TLS before issuing the LOGIN command.

   S: {to M} Submission server assembles the complete message and if the
   assembly succeeds it acknowledges acceptance of the message by
   sending 250 response to the last BDAT command:

         S: 250 2.5.0 Ok, message accepted.

   M: {to I} The client marks the message containing the forwarded
   attachment on the IMAP server.

         M: A0053 UID STORE 25627 +FLAGS.SILENT ($Forwarded)
         I: * 215 FETCH (UID 25627 MODSEQ (12121231000))
         I: A0053 OK STORE completed

   Note: the UID STORE command shown above will only work if the marked
   message is in the currently selected mailbox; otherwise, it requires
   a SELECT.  As in the previous example, this command is not critical,
   and can be omitted.  The untagged FETCH response is due to [RFC4551].
   The $Forwarded IMAP keyword is described in Section 3.8.

3.5.  Normative statements related to forward without download

   Lemonade compliant IMAP servers MUST support IMAPv4Rev1 [RFC3501],
   CATENATE [RFC4469], UIDPLUS [RFC4315] and URLAUTH [RFC4467].  This
   support MUST be declared via CAPABILITY [RFC3501].

   Lemonade compliant submit servers MUST support the BURL [RFC4468],
   8BITMIME [RFC1652], BINARYMIME [RFC3030] and CHUNKING [RFC3030].
   This support MUST be declared via EHLO [RFC2821].  BURL MUST support
   URLAUTH type URLs [RFC4467], and thus MUST advertise the "imap"
   option following the BURL EHLO keyword (See [RFC4468] for more
   details).

   Additional normative statements are provided in other sections.

3.6.  Security Considerations for pawn-tickets.

   The so-called "pawn-ticket" authorization mechanism uses a URI, which
   contains its own authorization credentials using [RFC4467].  The
   advantage of this mechanism is that the SMTP submit [RFC4409] server
   cannot access any data on the [RFC3501] server without a "pawn-
   ticket" created by the client.

   The "pawn-ticket" grants access only to the specific data that the



Maes, et al.            Expires December 31, 2006              [Page 16]

Internet-Draft            LEMONADE profile bis                 June 2006


   SMTP submit [RFC4409] server is authorized to access, can be revoked
   by the client, and can have a time-limited validity.

3.7.  Copies of Sent messages: The fcc problem

   The "fcc problem" refers to delivering a copy of a message to a
   mailbox, or "file carbon copy".  By far, the most common case of fcc
   is a client leaving a copy of outgoing mail in a "Sent Mail" or
   "Outbox" mailbox.

   In the traditional strategy, the MUA duplicates the effort spent in
   transmitting to the MSA by writing the message to the fcc destination
   in a separate step.  This may be a write to a local disk file or an
   APPEND to a mailbox on an IMAP server.  The latter is one of the "
   repetitive network data transmissions" which represents the "problem"
   aspect of the "fcc problem".

   The BURL [RFC4468] extension can be used to eliminate the additional
   transmission.  The final message is uploaded to the mailbox designed
   for outgoing mail, by the APPEND command of [RFC3501].  Note that
   APPEND, including when enhanced by [RFC4469], can only create a
   single message and this is only of use on the server which stages the
   outgoing message for submission.  Additional copies of the message
   can be created on the same server using one or more COPY commands.

3.8.  Registration of $Forwarded IMAP keyword

   The $Forwarded IMAP keyword is used by several IMAP clients to
   specify that the marked message was forwarded to another email
   address, embedded within or attached to a new message.  A mail client
   sets this keyword when it successfully forwards the message to
   another email address.  Typical usage of this keyword is to show a
   different (or additional) icon for a message that has been forwarded.
   Once set the flag SHOULD NOT be cleared.

   Lemonade compliant servers MUST be able to store the $Forwarded
   keyword.  They MUST preserve it on the COPY operation.  The servers
   MUST support the SEARCH KEYWORD $Forwarded.


4.  Message Submission

   LEMONADE compliant mail submission servers are expected to implement
   the following set of SMTP extensions to make message submission
   efficient.

   Lemonade clients should take advantage of these features.




Maes, et al.            Expires December 31, 2006              [Page 17]

Internet-Draft            LEMONADE profile bis                 June 2006


4.1.  Pipelining

   Mobile clients regularly use networks with a relatively high latency.
   Avoidance of round-trips within a transaction has a great advantage
   for the reduction in both bandwidth and total transaction time.  For
   this reason LEMONADE compliant mail submission servers MUST support
   the SMTP Service Extensions for Command Pipelining [RFC2197].

   Clients SHOULD pipeline SMTP commands when possible.

4.2.  DSN Support

   LEMONADE compliant mail submission servers MUST support SMTP service
   extensions for delivery status notifications [RFC3461].

4.3.  Message size declaration

   LEMONADE compliant mail submission servers MUST support the SMTP
   Service Extension for Message Size Declaration [RFC1870].

   LEMONADE compliant mail submission servers MUST resolve all BURL
   parts before enforcing a message size limit.

   A LEMONADE compliant client SHOULD use message size declaration.  In
   particular the client MUST NOT send a message to a mail submission
   server, if it knows that the message exceeds the maximal message size
   advertised by the submission server.  When including a message size
   in the MAIL FROM command, the client MUST use a value that is at
   least as large as the size of the assembled message data after
   resolution of all BURL parts.

4.4.  Enhanced status code Support

   LEMONADE compliant mail submission servers MUST support SMTP Service
   Extension for Returning Enhanced Error Codes [RFC2034].

4.5.  TLS

   LEMONADE Compliant mail submission servers MUST support SMTP Service
   Extension for Secure SMTP over TLS [RFC3207].


5.  Message Store

   Lemonade compliant message store services provide an IMAP service
   with the following set of extensions in order to provide both
   efficient access to the message store and support constrained devices
   more effectively.



Maes, et al.            Expires December 31, 2006              [Page 18]

Internet-Draft            LEMONADE profile bis                 June 2006


5.1.  Quick resynchronization

   LEMONADE Compliant IMAP servers MUST support the CONDSTORE [RFC4551]
   extension.  It allows a client to quickly resynchronize any mailbox
   by asking the server to return all flag changes that have occurred
   since the last known mailbox synchronization mark.

   [RFC4549] shows how to perform quick mailbox resynchronization.

   In addition, LEMONADE Compliant IMAP servers MUST support the
   RECONNECT [I-D.ietf-lemonade-reconnect] extension to provide quick
   reconnection facilities in case the transport layer is cut, whether
   accidentally or as part of a change in network.

5.2.  Message part handling

   LEMONADE Compliant IMAP servers MUST support the BINARY [RFC3516]
   extension.  This moves MIME body part decoding operations from the
   client to the server.  The decoded data is equal or less than the
   encoded representation, so this reduces bandwidth effectively.

   [RFC3516] allows for servers to refuse to accept uploaded messages
   containing binary data, however LEMONADE Compliant IMAP servers SHALL
   always accept binary encoded MIME messages in APPEND commands for any
   folder.

   [I-D.ietf-lemonade-convert] MUST also be supported by servers, which
   allows clients to request conversions between media types, and allows
   for scaling images, etc.  This provides the ability to view
   attachments (and sometimes body parts) without the facility to cope
   with a wide range of media types, or to efficiently view attachments.

5.3.  Compression

   The IETF has for some time generally agreed that compression is best
   handled at as low a level as possible, therefore Lemonade compliant
   IMAP servers SHOULD support the Deflate compression algorithm for
   TLS, as defined in [RFC3749].

   However, the working group acknowledges that for many endpoints, this
   is a rarely deployed technology, as as such, Lemonade compliant IMAP
   servers MUST provide [I-D.gulbrandsen-imap-deflate] support for
   fallback application-level stream compression, where TLS is not
   actively providing compression.

5.4.  Out of band notifications

   Server to client notifications as discussed in [I-D.ietf-lemonade-



Maes, et al.            Expires December 31, 2006              [Page 19]

Internet-Draft            LEMONADE profile bis                 June 2006


   notifications].  Server to server notifications discussed in
   [I-D.ietf-lemonade-notifications] describes how NF interacts with the
   notifications mechanisms.

   <<Editor's Note: This is a placeholder section, awaiting
   clarification of notifications.>>

5.5.  Virtual Mailboxes

   Lemonade compliant IMAP servers provide a mechanism for clients to
   avoid handling an entire mailbox, instead accessing a view of the
   mailbox defined previously.  This technique, common in many desktop
   clients as a client-side capability, is useful for constrained
   clients to minimize the quantity of messages and notification data.

   This virtual folder mechanism is defined in [I-D.ietf-lemonade-
   vfolder].

   <<Editor's Note: Virtual Mailboxes are currently an open issue.>>

5.6.  Additional IMAP extensions

   Lemonade compliant IMAP servers MUST support the NAMESPACE [RFC2342]
   extension.  The extension allows clients to discover shared mailboxes
   and mailboxes belonging to other users, and provide a normalized
   heirarchy view of the mailboxes available.

   Lemonade compliant IMAP servers MUST support the LITERAL+ [RFC2088]
   extension.  The extension allows clients to save a round trip each
   time a non-synchronizing literal is sent.

   Lemonade compliant IMAP servers MUST support the ESEARCH
   [I-D.melnikov-imap-search-ret] extension.  The extension allows
   clients to efficiently find the first or last messages, find a count
   of matching messages, and obtain a list of matching messages in a
   considerably more compact representation.

   Lemonade compliant IMAP servers MUST support the METADATA [I-D.daboo-
   imap-annotatemore] extension.  This allows metadata to be stored
   against mailboxes, which is a facility used by other extensions
   mandated by this profile.

   Lemonade compliant IMAP servers MUST support the IDLE [RFC2177]
   extension.  The extension allows clients to receive unsolicited
   notifications about changes in the selected mailbox, without needing
   to poll for changes.  The responses forming these notifications MUST
   be sent in a timely manner when such changes happen.




Maes, et al.            Expires December 31, 2006              [Page 20]

Internet-Draft            LEMONADE profile bis                 June 2006


   Lemonade Compliant IMAP servers MUST support IMAP over TLS [RFC3501]
   as required by [RFC3501].  As noted above in Section 5.3, servers
   SHOULD support the deflate compression algorithm for TLS, as
   specified in [RFC3749]


6.  Summary of the required IMAP and SMTP extensions

   +-------------------------+----------------------------------------+
   |  Name of SMTP extension |                 Comment                |
   +-------------------------+----------------------------------------+
   |        PIPELINING       |               Section 4.1              |
   |           DSN           |               Section 4.2              |
   |           SIZE          |               Section 4.3              |
   |   ENHANCEDSTATUSCODES   |               Section 4.4              |
   |         STARTTLS        |               Section 4.5              |
   |           BURL          |                Section 3               |
   | URLAUTH support in BURL |                Section 3               |
   |   CHUNKING, BINARYMIME  |               Section 3.5              |
   |         8BITMIME        |            Required by BURL            |
   |           AUTH          |  Required by Submission. See [RFC2554] |
   +-------------------------+----------------------------------------+

    +-----------------------------------+----------------------------+
    | Name of IMAP extension or feature |           Comment          |
    +-----------------------------------+----------------------------+
    |             NAMESPACE             |         Section 5.6        |
    |             CONDSTORE             |         Section 5.1        |
    |              STARTTLS             | Required by IMAP [RFC3501] |
    |     URLAUTH, CATENATE, UIDPLUS    |          Section 3         |
    |              LITERAL+             |         Section 5.6        |
    |                IDLE               |         Section 5.6        |
    |      $Forwarded IMAP keyword      |         Section 3.8        |
    |               BINARY              |         Section 5.2        |
    |             RECONNECT             |         Section 5.1        |
    |              ESEARCH              |         Section 5.6        |
    |              VFOLDER              |         Section 5.5        |
    |              CONVERT              |         Section 5.2        |
    |          COMPRESS=DEFLATE         |         Section 5.3        |
    |              METADATA             |         Section 5.6        |
    +-----------------------------------+----------------------------+


7.  OMA MEM Requirement document

   The OMA MEM activity has collected a set of use cases and derived
   requirements for a mobile email enabler (MEM). the resulting work is
   summarized in OMA MEM Requirement document [MEM-req].  Some



Maes, et al.            Expires December 31, 2006              [Page 21]

Internet-Draft            LEMONADE profile bis                 June 2006


   requirements relates to email protocols, some involve other OMA
   technologies outside the scope of IETF and some relate to
   implementations and normative interoperability statements for clients
   and servers.

7.1.  OMA MEM Architecture

   The OMA MEM activity has derived a logical architecture from the
   requirements and use cases described in [MEM-req].  The logical
   architecture, its elements and interfaces and the notations that it
   uses can be found in [MEM-arch].

7.2.  OMA MEM Deployment Issues

   The OMA MEM Architecture document [MEM-arch] further identifies
   deployment models.

   Certain of these deployment models are not what IETF has
   conventionally modeled.  They require special attention to end-to-end
   security aspects and may warrant introduction of additional security
   measures (e.g. object level encryption).

7.3.  OMA MEM proxy

   The OMA MEM Architecture document [MEM-arch] identifies OMA MEM
   server proxies as server components that may be deployed ahead of
   firewalls to facilitate traversal of firewalls.

   Both IMAP and SMTP generally are compatible with proxies between the
   client and the server.  Such proxies may disrupt end-to-end
   encryption, with the transport-level encryption ending at the proxy
   and re-generating from the proxy to the server.  Again this may
   require additional security measures like object level encryption.

7.4.  IETF LEMONADE Architecture

   This section gives a brief introduction to the LEMONADE Architecture.

   The IETF LEMONADE activity has derived a profile with the logical
   architecture represented in Figure 15, where arrows indicate content
   flows.










Maes, et al.            Expires December 31, 2006              [Page 22]

Internet-Draft            LEMONADE profile bis                 June 2006


                            ______________
                           |              |
                  _________| Notification |
                 |         | Mechanism    |
                 |         |______________|
                 |Notif.              ^
                 |Protocol            |
                 |                 ___|______
                 |                |          |                 _____
               __v__    IMAP      | LEMONADE |      ESMTP     |     |
              |     |<----------->| IMAP     |<---------------| MTA |
              | MUA |-            | Store    |                |_____|
              |_____| \           |__________|
                       \               |
                        \              |URLAUTH
                         \SUBMIT       |
                          \        ____v_____
                           \      |          |                 _____
                            \     | LEMONADE |      ESMTP     |     |
                             ---->| Submit   |--------------->| MTA |
                                  | Server   |                |_____|
                                  |__________|

   Figure 15: LEMONADE logical architecture

   The LEMONADE profile assumes: <<Editor's note: remove redundant
   information from the list below.>>
   o  IMAP protocol [RFC3501] including LEMONADE profile extensions
   o  Submit protocol ([RFC4409], profile of [RFC2821]) including
      LEMONADE profile extensions
   o  LEMONADE profile compliant IMAP store connected to MTA (Mail
      Transfer Agent) via ESMTP [RFC2821].
   o  LEMONADE profile compliant Submit server connected to MTA via
      ESMTP
   o  Lemonade profile message store / Submit server protocols (URLAUTH)
      (see [RFC4467]).
   o  Outband server to client notifications relying on external
      notification mechanisms (and notification protocols) that may be
      out of scope of the LEMONADE profile.
   o  A LEMONADE aware MUA (Mail User Agent).  While use of outband
      notification is described in the LEMONADE profile, support for the
      underlying notifications mechanisms/protocols is out of scope of
      the LEMONADE specifications.

   Further details on the IETF email protocol stack and architecture can
   be found in [I-D.crocker-email-arch]

   Note that in Figure 15 the IMAP server and Submit server are



Maes, et al.            Expires December 31, 2006              [Page 23]

Internet-Draft            LEMONADE profile bis                 June 2006


   represented connected to MTAs (Mail Transfer Agents) via ESMTP
   [RFC1861].  This is not really essential.  It could as well be X.400
   so long as the message in the store is in the internet form.

   OMA MEM identifies other functionalities.  These are considered as
   out of scope of the LEMONADE work and will need to be specified by
   OMA MEM.

7.5.  LEMONADE profile logical architecture

   This section details the LEMONADE profile logical architecture.  This
   architecture is also expected to support the OMA MEM logical
   Architecture.

7.5.1.  Relationship between the OMA MEM and LEMONADE logical
        architectures

   Figure 16 illustrates the mapping of the IETF LEMONADE logical
   architecture on the OMA MEM logical architecture.
































Maes, et al.            Expires December 31, 2006              [Page 24]

Internet-Draft            LEMONADE profile bis                 June 2006


                          _____________________
                         | Other_Mob. Enablers |
                         | |--------------|    |
                  _________| Notification |    |
                 |       | | Mechanism    |    |
                 |       | |______________|    |
                 |Notif. |____________^________|
                 |Protocol      ______|__________
            ME-4 |             |   ___|_ME-3_    |
              ___|____         |  |          |   |         _____
             | __v__ |  IMAP   |  | LEMONADE |   |  ESMTP |     |
             ||     |<----------->| IMAP     |<-----------| MTA |
             || MUA ||   ME-2a |  | Store    |   |        |_____|
             ||_____||\ME-1    |  |__________|   |
             | MEM   | \       |       |         |
             | Client|  \      |       |URLAUTH  |
             |_______|   \SUBMIT       |         |
                          \    |   ____v_____    |
                           \   |  |          |   |         _____
                            \  |  | LEMONADE |   |  ESMTP |     |
                             ---->| Submit   |----------->| MTA |
                         ME-2b |  | Server   |   |        |_____|
                               |  |__________|   |
                               |MEM        Email |
                               |Server     Server|
                               |_________________|
                                        ^
                                        |ME-5
                                        |

   Figure 16: Mapping of LEMONADE profile logical architecture  onto the
   OMA MEM logical architecture.

   As described in Section 7.4, the LEMONADE profile assumes LEMONADE
   profile compliant IMAP stores and Submit servers.  Because the
   LEMONADE profile extends the IMAP store and the submit server, the
   mobile enablement of email provided by the LEMONADE profile is
   directly provided in these server.  Mapped to OMA MEM logical
   architecture, for the case considered and specified by the LEMONADE
   profile, the MEM server and email server logically combined.  They
   are however split into distinct LEMONADE message store and LEMONADE
   submit server.  The OMA MEM interfaces ME-2 ([MEM-arch]) consists of
   two interfaces ME-2a and ME-2b associated respectively to IMAP
   extended according to the LEMONADE profile and SUBMIT extended
   according to the LEMONADE profile.

   The MUA is part of the MEM client.




Maes, et al.            Expires December 31, 2006              [Page 25]

Internet-Draft            LEMONADE profile bis                 June 2006


   External notifications mechanism can be part of the other OMA enabler
   specified by OMA (or other activities).

7.5.2.  LEMONADE realization of OMA MEM with non-LEMONADE compliant
        servers

   The OMA MEM activity is not limited to enabling Lemonade compliant
   servers.  It explicitly identifies the need to support other
   backends.

7.5.2.1.  LEMONADE realization of OMA MEM with non-LEMONADE enhanced
          IMAP servers

   Figure 17 illustrates the case of IMAP servers that are not (yet)
   LEMONADE compliant / enhanced with LEMONADE.  In such case, the I2
   interface between the MEM server components and the IMAP store and
   submit server are IMAP and SUBMIT.


                 ______________
                |              |
       _________| Notification |
      |         | Mechanism    |
      |         |______________|
      |Notif.            ^
      |Protocol          |
      |               ___|______          _____________
      |              | LEMONADE |        |             |        _____
    __v__    IMAP    | MEM      |  IMAP  |NON-LEMONADE | ESMTP |     |
   |     |<--------->|Enabler   |<------>|IMAP         |<----->| MTA |
   | MUA |\   ME-2a  | Server   |        |Store        |       |_____|
   |_____| \         |__________|        |_____________|
            \             |
             \            |URLAUTH
              \SUBMIT     |
               \      ____v_____          _____________
                \    |          |        |             |        _____
                 \   | LEMONADE | SUBMIT |NON-LEMONADE | ESMTP |     |
                  -->|  MEM     |        |Submit       |       |     |
                     | Enabler  |------->|Server       |------>| MTA |
              ME-2b  | Server   |        |             |       |_____|
                     |__________|        |_____________|


   Figure 17: Architecture to support non-LEMONADE enhanced IMAP
   servers with a LEMONADE realization of OMA MEM enabler.

   In Figure 17, the server may be a separate proxy.



Maes, et al.            Expires December 31, 2006              [Page 26]

Internet-Draft            LEMONADE profile bis                 June 2006


7.5.2.2.  LEMONADE realization of OMA MEM with non-IMAP servers

   <<Editor's note: This section and the previous section and figures
   may be combined in a future release of this draft.>

   Figure 18 illustrates the cases where the message store and submit
   servers are not IMAP store or submit servers.  They may be POP3
   servers or other proprietary message stores.

                 ______________
                |              |
       _________| Notification |
      |         | Mechanism    |
      |         |______________|
      |Notif.            ^
      |Protocol          |
      |               ___|______          _____________
      |              | LEMONADE |        |             |        _____
    __v__    IMAP    | MEM      |    I2  |Proprietary  | ESMTP |     |
   |     |<--------->|Enabler   |<------>|Message      |<----->| MTA |
   | MUA |\   ME-2a  | Server   |        |Store        |       |_____|
   |_____| \         |__________|        |_____________|
            \             |
             \            |URLAUTH
              \SUBMIT     |
               \      ____v_____          _____________
                \    |          |        |             |        _____
                 \   | LEMONADE |    I2  |Proprietary  | ESMTP |     |
                  -->| MEM      |        |Submit       |       |     |
                     | Enabler  |------->|Server       |------>| MTA |
              ME-2b  | Server   |        |             |       |_____|
                     |__________|        |_____________|


   Figure 18: Architecture to support non-IMAP servers with a LEMONADE
   realization of OMA MEM enabler.

   I2 designates proprietary adapters to the backends.  They may
   involved functions performed in the message stores or submit server
   as well as in the MEM enabler server.

   In Figure 18, the server may be a separate proxy.

7.6.  Filters and server to client notifications and LEMONADE

   OMA MEM RD [MEM-req] and AD [MEM-arch] emphasize the need to provide
   mechanisms for server to client notifications of email events and
   filtering.  Figure 19 illustrates how notification and filterings are



Maes, et al.            Expires December 31, 2006              [Page 27]

Internet-Draft            LEMONADE profile bis                 June 2006


   introduced in LEMONADE profile.



                   ______________
                  |              |
         _________| Notification |
        |         | Mechanism    |
        |         |______________|
        |Notif.              ^
        |Protocol -------\  _|_
        |   ______|    ___\>|NF|____
        |  |          |     ----    |                 _____
      __v__|   IMAP   |__  LEMONADE |___   ESMTP   __|     |
     |     |<-------->|VF| IMAP     |DF |<--------|AF| MTA |
     | MUA |\   ME-2a |--  Store    |---           --|_____|
     |_____| \        |_____________| ^
            \_\_______________|_______|
               \              |URLAUTH
                \SUBMIT       |
                 \        ____v_____
                  \      |          |                 _____
                   \     | LEMONADE |      ESMTP     |     |
                    ---->| Submit   |--------------->| MTA |
                ME-2b    | Server   |                |_____|
                         |__________|


   Figure 19: Filtering mechanism defined in LEMONADE architecture

   In Figure 19, four categories of filters are defined:
   o  AF: Administrative Filters - Set up by email service provider.  AF
      are typically not configured by the user and set to apply policies
      content filtering, virus protection, spam filtering etc...
   o  DF: Deposit Filters - Filters that are executed on deposit of new
      email messages.  They can be defined as SIEVE filters [SIEVE].
      They can include vacation notices.
   o  VF: View Filters - Filters that define which emails are visible to
      the MUA.  View filters can be defined as virtual folders
      [I-D.ietf-lemonade-vfolder] as described in [I-D.ietf-lemonade-
      vfolder] and [I-D.ietf-lemonade-notifications].
   o  NF: Notification Filters - Filters that define for what email
      server event an outband notification is sent to the client.

   The filters are manageable from the MUA:
   o  NF and DF: via SIEVE Management protocol [I-D.martin-managesieve]





Maes, et al.            Expires December 31, 2006              [Page 28]

Internet-Draft            LEMONADE profile bis                 June 2006


   o  VF: via virtual folder mechanisms as discussed in [I-D.ietf-
      lemonade-vfolder] and [I-D.ietf-lemonade-notifications]

7.7.  LEMONADE Profile features

   <<Editor's note: This section will be empty before publication, other
   sections would contain detailed description of features listed in
   this section.>>

   The LEMONADE Profile provides normative support for the technical
   features identified within scope of IETF LEMONADE work in the OMA MEM
   realization internet draft.

   The following is a list of features that will be normatively
   described: <<Editor's note: The features are currently introduced by
   reference to documents that are work in progress and may still be
   individual drafts.  They are expected to become WG drafts and RFCs.
   References will be updated and text provided to explain the normative
   usage in LEMONADE profile.>>
   o  LEMONADE profile features, evolved to include capabilities to edit
      on MUA and send differences to server even for address fields.
   o  Server to client notifications as discussed in [I-D.ietf-lemonade-
      notifications].  Server to server notifications discussed in
      [I-D.ietf-lemonade-notifications] describes how NF interacts with
      the notifications mechanisms.
   o  Filters as discussed in [I-D.ietf-lemonade-notifications],
      [I-D.ietf-lemonade-vfolder], [I-D.ietf-lemonade-search-within],
      [SIEVE] and [I-D.ietf-lemonade-imap-sieve].  Events that can be
      bound to notifications are described in [I-D.ietf-lemonade-
      msgevent].  Filter remote management are discussed in [I-D.ietf-
      lemonade-notifications] and [I-D.ietf-lemonade-vfolder].  For NF,
      it MAY rely on [I-D.martin-managesieve]
   o  Virtual folders as discussed in [I-D.ietf-lemonade-vfolder]
   o  Media conversion as discussed in [I-D.ietf-lemonade-convert].
      Streamed media conversion is still under consideration.
   o  Quick reconnect as discussed in [I-D.ietf-lemonade-reconnect]
   o  Compression as discussed in [I-D.gulbrandsen-imap-deflate].
   o  Intermediaries as discussed in [I-D.smaes-lemonade-intermediary-
      challenges].  Best practices are discussed in [I-D.ietf-lemonade-
      deployments].  Lemonade protocols MAY also follow [I-D.maes-
      lemonade-tcp-challenged-environments]
   o  Proxies and other intermediaries that provide protocol support
      disrupt conventional IETF security models and require object level
      encryption as discussed in [I-D.ietf-lemonade-convert].
      [I-D.ietf-lemonade-notifications] further discusses the use for
      notification encryption.





Maes, et al.            Expires December 31, 2006              [Page 29]

Internet-Draft            LEMONADE profile bis                 June 2006


   o  Message recall within SUBMIT domain based on [RFC3888].


8.  Security Considerations

   Security considerations on Lemonade "forward without download" are
   discussed throughout Section 3.  Additional security considerations
   can be found in [RFC3501] and other documents describing other SMTP
   and IMAP extensions comprising the Lemonade Profile.

   Note that the mandatory-to-implement authentication mechanism for
   SMTP submission is described in [RFC4409].  The mandatory-to-
   implement authentication mechanism for IMAP is described in
   [RFC3501].

8.1.  Confidentiality Protection of Submitted Messages

   When clients submit new messages, link protection such as TLS guards
   against an eavesdropper seeing the contents of the submitted message.
   It's worth noting, however, that even if TLS is not used, the
   security risks are no worse if BURL is used to reference the text
   than if the text is submitted directly.  If BURL is not used, an
   eavesdropper gains access to the full text of the message.  If BURL
   is used, the eavesdropper may or may not be able to gain such access,
   depending on the form of BURL used.  For example, some forms restrict
   use of the URL to an entity authorized as a submission server or a
   specific user.

8.2.  TLS

   When LEMONADE clients use the BURL extension to mail submission, an
   extension that requires sending a URLAUTH token to the mail
   submission server, such a token should be protected from interception
   to avoid a replay attack that may disclose the contents of the
   message to an attacker.  TLS based encryption of the mail submission
   path will provide protection against this attack.

   LEMONADE clients SHOULD use TLS-protected IMAP and mail submission
   channels when using BURL-based message submission to protect the
   URLAUTH token from interception.

   LEMONADE compliant mail submission servers SHOULD use TLS-protected
   IMAP connections when fetching message content using the URLAUTH
   token provided by the LEMONADE client.

   When a client uses SMTP STARTTLS to send a BURL command which
   references non-public information, there is a user expectation that
   the entire message content will be treated confidentially.  To meet



Maes, et al.            Expires December 31, 2006              [Page 30]

Internet-Draft            LEMONADE profile bis                 June 2006


   this expectation, the message submission server should use STARTTLS
   or a mechanism providing equivalent data confidentiality when
   fetching the content referenced by that URL.

8.3.  Additional extensions and deployment models

   This specification provides no additional security measures beyond
   those in the referenced Internet Mail and LEMONADE documents.

   We note however the security risks associated to:
   o  Outband notifications
   o  Server configuration by client
   o  Client configuration by server
   o  Presence of proxy servers
   o  Presence of servers as intermediaries
   o  In general the deployment models considered by OMA MEM that are
      not conventional IETF deployment models.
   o  Measures to address the need to traverse firewalls and mobile
      network intermediaries.


9.  IANA considerations

   This document doesn't require any IANA registration or action that
   are not covered by the different drafts and RFCs included in the
   realization described in this document.

   We note the reserved mailbox / folder names in [I-D.ietf-lemonade-
   vfolder].


10.  Future work

   o  The different drafts and RFCs referenced in this document must be
      completed and separated into normative and informative references.
   o  Text will be updated as described in editor's notes


11.  Version history

   o  Version 02:
      *  Update of references and how they are displayed in the text
         (Comments from Randy Gellens)
      *  Update of list of extensions to support as MUST by the Lemonade
         Profile Bis
      *  Update of options for compression via placeholder imap-
         compression section describing compression requirements




Maes, et al.            Expires December 31, 2006              [Page 31]

Internet-Draft            LEMONADE profile bis                 June 2006


      *  Update of support of TCP chalenged environments
      *  Update of support of object level encryption
      *  Clarified the use of $Forwarded in the examples, and
         demonstrated how to remove the \Draft flag from the sent
         message
      *  Clarified $Forwarded
      *  Added RECONNECT to imap-condstore section
      *  Add new section imap-bodypart, "Message part handling",
         describing BINARY and CONVERT requirements
      *  Added placeholder section for notifications
      *  Added various extensions to imap-other section, and added
         clarifying comments to IDLE, NAMESPACE, and a further
         references to TLS DEFLATE compression
      *  Added extension names to IMAP table
      *  Fixed all issues found with original Lemonade profile so far.
   o  Version 01:
      *  LEMONADE profile has been introduced in-line, with some updates
         / corrections.
      *  Subsequent re-organization of the text
      *  Details of extensions proper to Lemonade Profile-bis have been
         updated to refer to the drafts newly accepted as WG IETF
         drafts.
      *  Addition of appendix on attachements streaming.
   o  Version 00:
      *  It evolved from a combination of the content of LEMONADE
         profile and the OMA MEM realization internet draft.


12.  Acknowledgements

   The editors acknowledge and appreciate the work and comments of the
   IETF LEMONADE working group and the OMA MEM working group.

   In particular, the editors would like to thank Eric Burger, Randall
   Gellens, Zoltan Ordogh, Greg Vaudreuil, and Fan Xiaohui for their
   comments and reviews.


Appendix A.  Streaming attachments

   <<Editor's note: This section is introduced as a reminder that a
   draft is due on this topic.  It is expected to be moved to that
   draft.  Otherwise, it may be expanded and remain in this document
   (possibly as a main section) when well enough documented.>>

   <<Editor's note: Support for this capability is expected to remain
   optional.>>




Maes, et al.            Expires December 31, 2006              [Page 32]

Internet-Draft            LEMONADE profile bis                 June 2006


     +----------+          +--------+       +---------+
     | LEMONADE |    (2)   | Media  |  (3)  | Media   |
     |  IMAP    |<-------->| Server |<----->|Converter|
     | Store    |          |        |       |         |
     +----------+          +--------+       +---------+
          ^                     ^
          |                     |
          |(1)                  |
          |                     |(4)
          |                     |
     +----V---+                 |
     |        |                 |
     | Client <-----------------|
     |        |
     +--------+


   Figure 20: LEMONADE architecture to support streaming and conversion
   of attachments

   In Figure 20:
   o  (1) Designates:
      *  (a) The request (to be defined by Lemonade) for content
         streaming (possibly with conversion) sent by the client to the
         IMAP store.
      *  (b) The response from the IMAP store (if any).
   o  (2) Designates:
      *  A yet to be defined rest to initiate streaming of converted
         content to the client.
      *  The response
   o  (3) Designates :
      *  (a) A yet to be defined request by the media server to convert
         content as requested by the client.  This could be based on OMA
         STI. <<Editor's note: Reference will be added later.>>
      *  (b) The response
   o  (4) Designates:
      *  (a) The signaling between the Media Server and the client to
         initiate and control streaming of the media
      *  (b) The actual media streaming
   o  This could involve SIP, RTP, RTSP, ... <<Editor's note: References
      will be added later after details are agreed upon.>>
   o  <<Editor's note: Open issue: Could IMAP store issue the signalling
      (e.g.  SIP third party call control) or does it have to be solely
      between client and media server>>


13.  References




Maes, et al.            Expires December 31, 2006              [Page 33]

Internet-Draft            LEMONADE profile bis                 June 2006


13.1.  Normative References

   [I-D.crocker-email-arch]
              Crocker, D., "Internet Mail Architecture",
              draft-crocker-email-arch-04 (work in progress),
              March 2005.

   [I-D.daboo-imap-annotatemore]
              Daboo, C., "IMAP METADATA Extension",
              draft-daboo-imap-annotatemore-09 (work in progress),
              March 2006.

   [I-D.gulbrandsen-imap-deflate]
              Gulbrandsen, A., "The IMAP COMPRESS=DEFLATE extension",
              draft-gulbrandsen-imap-deflate-02 (work in progress),
              March 2006.

   [I-D.ietf-lemonade-convert]
              Maes, S. and R. Cromwell, "CONVERT",
              draft-ietf-lemonade-convert-04 (work in progress),
              June 2006.

   [I-D.ietf-lemonade-imap-sieve]
              Leiba, B., "Support for Sieve in Internet Message Access
              Protocol (IMAP4)", draft-ietf-lemonade-imap-sieve-01 (work
              in progress), March 2006.

   [I-D.ietf-lemonade-msgevent]
              Newman, C., "Internet Message Store Events",
              draft-ietf-lemonade-msgevent-00 (work in progress),
              June 2006.

   [I-D.ietf-lemonade-notifications]
              Cromwell, R. and S. Maes, "Lemonade notifications and
              filters", draft-ietf-lemonade-notifications-03 (work in
              progress), June 2006.

   [I-D.ietf-lemonade-reconnect]
              Wilson, C. and A. Melnikov, "IMAP4 Extensions for Quick
              Reconnect", draft-ietf-lemonade-reconnect-07 (work in
              progress), June 2006.

   [I-D.ietf-lemonade-search-within]
              Maes, S. and R. Cromwell, "WITHIN Search extension to the
              IMAP Protocol", draft-ietf-lemonade-search-within-02 (work
              in progress), June 2006.

   [I-D.ietf-lemonade-vfolder]



Maes, et al.            Expires December 31, 2006              [Page 34]

Internet-Draft            LEMONADE profile bis                 June 2006


              Maes, S., "Persistent Virtual Folder extension to the IMAP
              Protocol", draft-ietf-lemonade-vfolder-01 (work in
              progress), May 2006.

   [I-D.martin-managesieve]
              Martin, T. and A. Melnikov, "A Protocol for Remotely
              Managing Sieve Scripts", draft-martin-managesieve-06 (work
              in progress), February 2006.

   [I-D.melnikov-imap-search-ret]
              Melnikov, A. and D. Cridland, "IMAP4 extension to SEARCH
              command for controlling what kind of information  is
              returned", draft-melnikov-imap-search-ret-03 (work in
              progress), June 2006.

   [MEM-arch]
              Open Mobile Alliance, "Mobile Email Architecture
              Document", OMA (Work in Progress),
              http://www.openmobilealliance.org/, October 2005.

   [MEM-req]  Open Mobile Alliance, "Mobile Email Requirements
              Document", OMA http://www.openmobilealliance.org/
              release_program/docs/RD/
              OMA-RD-MobileEmail-V1_0_20051018-C.pdf, Oct 2005.

   [RFC1652]  Klensin, J., Freed, N., Rose, M., Stefferud, E., and D.
              Crocker, "SMTP Service Extension for 8bit-MIMEtransport",
              RFC 1652, July 1994.

   [RFC1861]  Gwinn, R., "Simple Network Paging Protocol - Version 3
              -Two-Way Enhanced", RFC 1861, October 1995.

   [RFC1870]  Klensin, J., Freed, N., and K. Moore, "SMTP Service
              Extension for Message Size Declaration", STD 10, RFC 1870,
              November 1995.

   [RFC2034]  Freed, N., "SMTP Service Extension for Returning Enhanced
              Error Codes", RFC 2034, October 1996.

   [RFC2088]  Myers, J., "IMAP4 non-synchronizing literals", RFC 2088,
              January 1997.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2177]  Leiba, B., "IMAP4 IDLE command", RFC 2177, June 1997.

   [RFC2197]  Freed, N., "SMTP Service Extension for Command



Maes, et al.            Expires December 31, 2006              [Page 35]

Internet-Draft            LEMONADE profile bis                 June 2006


              Pipelining", RFC 2197, September 1997.

   [RFC2342]  Gahrns, M. and C. Newman, "IMAP4 Namespace", RFC 2342,
              May 1998.

   [RFC2554]  Myers, J., "SMTP Service Extension for Authentication",
              RFC 2554, March 1999.

   [RFC2821]  Klensin, J., "Simple Mail Transfer Protocol", RFC 2821,
              April 2001.

   [RFC3030]  Vaudreuil, G., "SMTP Service Extensions for Transmission
              of Large and Binary MIME Messages", RFC 3030,
              December 2000.

   [RFC3207]  Hoffman, P., "SMTP Service Extension for Secure SMTP over
              Transport Layer Security", RFC 3207, February 2002.

   [RFC3461]  Moore, K., "Simple Mail Transfer Protocol (SMTP) Service
              Extension for Delivery Status Notifications (DSNs)",
              RFC 3461, January 2003.

   [RFC3501]  Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION
              4rev1", RFC 3501, March 2003.

   [RFC3516]  Nerenberg, L., "IMAP4 Binary Content Extension", RFC 3516,
              April 2003.

   [RFC3749]  Hollenbeck, S., "Transport Layer Security Protocol
              Compression Methods", RFC 3749, May 2004.

   [RFC3888]  Hansen, T., "Message Tracking Model and Requirements",
              RFC 3888, September 2004.

   [RFC4315]  Crispin, M., "Internet Message Access Protocol (IMAP) -
              UIDPLUS extension", RFC 4315, December 2005.

   [RFC4409]  Gellens, R. and J. Klensin, "Message Submission for Mail",
              RFC 4409, April 2006.

   [RFC4467]  Crispin, M., "Internet Message Access Protocol (IMAP) -
              URLAUTH Extension", RFC 4467, May 2006.

   [RFC4468]  Newman, C., "Message Submission BURL Extension", RFC 4468,
              May 2006.

   [RFC4469]  Resnick, P., "Internet Message Access Protocol (IMAP)
              CATENATE Extension", RFC 4469, April 2006.



Maes, et al.            Expires December 31, 2006              [Page 36]

Internet-Draft            LEMONADE profile bis                 June 2006


   [RFC4551]  Melnikov, A. and S. Hole, "IMAP Extension for Conditional
              STORE Operation or Quick Flag Changes Resynchronization",
              RFC 4551, June 2006.

   [SIEVE]    IETF, "SIEVE WG",
               http://www.ietf.org/html.charters/sieve-charter.html.

13.2.  Informative References

   [I-D.ietf-lemonade-deployments]
              Gellens, R., "Deployment Considerations for lemonade-
              compliant Mobile Email",
              draft-ietf-lemonade-deployments-03 (work in progress),
              June 2006.

   [I-D.maes-lemonade-tcp-challenged-environments]
              Maes, S. and R. Cromwell, "Lemonade in TCP Challenged
              Environments",
              draft-maes-lemonade-tcp-challenged-environments-01 (work
              in progress), June 2006.

   [I-D.smaes-lemonade-intermediary-challenges]
              Maes, S., "Lemonade and the challenges of Intermediaries",
              draft-smaes-lemonade-intermediary-challenges-02 (work in
              progress), November 2005.

   [RFC4549]  Melnikov, A., "Synchronization Operations for Disconnected
              IMAP4 Clients", RFC 4549, June 2006.























Maes, et al.            Expires December 31, 2006              [Page 37]

Internet-Draft            LEMONADE profile bis                 June 2006


Authors' Addresses

   Stephane H. Maes (editor)
   Oracle
   MS 4op634, 500 Oracle Parkway
   Redwood Shores, CA  94539
   USA

   Phone: +1-203-300-7786
   Email: stephane.maes@oracle.com


   Alexey Melnikov (editor)
   Isode Limited
   5 Castle Business Village
   36 Station Road
   Hampton, Middlesex  TW12 2BX
   UK

   Email: Alexey.Melnikov@isode.com


   Dave Cridland (editor)
   Inventure Systems Ltd
   21, Heol Bronwydd
   Caerfyrddin, Cymru  SA31 2AJ
   GB

   Email: dave.cridland@invsys.co.uk






















Maes, et al.            Expires December 31, 2006              [Page 38]

Internet-Draft            LEMONADE profile bis                 June 2006


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 78 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.

   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.


Acknowledgment

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




Maes, et al.            Expires December 31, 2006              [Page 39]


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