One document matched: draft-ema-vpim-cb-00.txt
Internet Draft D. Dunne
Document: draft-ema-vpim-cb-00.txt Nortel Networks
Category: Informational G. Parsons
Expires in Six Months Nortel Networks
July 14, 2000
Voice Messaging IMAP Client Behaviour
STATUS OF THIS MEMO:
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all provisions of Section 10 of RFC2026.
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Abstract
This document defines the expected behaviour of an IMAP client to
various aspects of a VPIM message.
Table of Contents
1. Introduction
1.1 Conventions Used in This Document
2. Message Icon
2.1 Proposed Mechanism
3. Sender's Number Column
3.1 Proposed Mechanism
4. Message Size
4.1 Proposed Mechanism
5. Media Viewer
5.1 Proposed Mechanism
6. Mark Message Read only if Primary Content Read
7. Security Considerations
8. References
9. Acknowledgements
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10. Author's Address
11. Full Copyright Statement
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1. Introduction
As Internet messaging evolves into Unified messaging, the term "e-
mail" no longer refers to text-only messages. Today's "e-mail" can
also have voice and/or fax parts, as well as text.
Each of voice, fax, and text have their own distinct characteristics,
which are intuitive to the user. For example, each of these
message types require a different media viewer (text editor for text,
audio player for voice, and image viewer for fax), and the
dimensions of message size are also different for all three
(kilobytes for text, seconds for voice, and pages for fax).
How the messaging client responds to, and acts on these differences
is termed "Client Behaviour". This is heavily dependant on the
concept of "Primary Content" [2], which defines whether the message
is a voice mail, fax, or text message. The client can utilize this
header to determine the appropriate behaviour for a particular
message.
Note that this document deals only with IMAP clients. Where
appropriate, this document suggests how some of the desired
behaviours may be implemented using IMAP, but these should be
properly defined in other specifications.
1.1 Conventions Used in This Document
In examples, "C:" and "S:" indicate lines sent by the client and
server respectively.
2. Message Icon
The preferred method to distinguish between voice, fax, and text
messages is with a visual cue, or icon.
As it is possible for the message to contain more than one media
type, the icon should describe the primary message content, as
defined by the "Primary-Content" header. Obvious choices for the
icon/message pairs would be a telephone for a voice message, a fax
machine for a fax message, and an envelope for a text message.
This could be taken a step further, and have the icon change to
indicate that the message has been read (as is currently done in
many email clients). For example, a telephone with the receiver off-
hook could indicate that the voice message has been played. A fax
machine with paper at the bottom, as opposed to the top, would show
that the fax had been viewed. Finally, as is currently the norm, an
open envelope indicates that a text message has been read.
2.1 Proposed Mechanism
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As the choice of icon is determined by the primary message type, the
client should obtain this information from the "Primary-Content"
message header. This header is defined in the Internet Draft draft-
burger-vpim-pc-00.txt [2].
3. Sender's Number Column
As is the case with most email clients today, important message
information is organized into columns when presented to the user.
Typical columns include the message subject, and the date the
message was received.
Another important piece of information for the user is the origin of
the message. For a voice or fax message, the origin is typically a
telephone or fax machine respectively, each of which has an
associated telephone number. This telephone number is critical to
the user if they wish to return the call.
3.1 Proposed Mechanism
There is currently a proposal to add a new Internet message header
to hold the originating telephone number [3]. The client should
extract this information, and display it to the user in a column.
As this header is defined to only hold the digits of the telephone
number, it is left to the client to add any separating characters
(e.g. "-").
4. Message Size
In the cases of large attachments, small clients and slow links
there is also a need for the client to see the length of the message
in a suitable format before opening it.
Currently, message size is normally given in kilobytes (kB). This
is sufficient for plain text messages, but it is not very useful in
terms of voice and fax. Instead, the size should give an indication
of the length of the message, i.e. the duration (in seconds) of a
voice message, and the number of pages of a fax. Again, the message
may contain multiple types, so the size displayed should be that of
the primary content type.
4.1 Proposed Mechanism
There are three suggested methods to relay this information, of them,
method 1 is favoured:
4.1.1 MIME Header Content-Duration as described in RFC 2424 [5]
For fax messages a new MIME Header, Content-Page-Length, would be
defined, similar to Content-Duration with the exception that number
of pages would be specified, rather than number of seconds. (e.g.
Content-Page-Length:3). This would be created at originator.
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4.1.2 FETCH item USERSIZE similar to FETCH items described in
IMAP4rev1 [6].
This would be created at reception.
4.1.2.1 USERSIZE is a non-negative number. Its meaning depends on
document type.
C: abc FETCH 1:2 (USERSIZE)
S: *1 FETCH (12)
S: *2 FETCH (57)
S: abc FETCH completed.
4.1.2.2 USERSIZE is a pair of number and unit. There is a small
set of unit tokens.
C: abc FETCH 1:2 (USERSIZE)
S: *1 FETCH (12 pages)
S: *2 FETCH (57 seconds)
S: abc FETCH completed.
4.1.2.3 USERSIZE is a sequence of pairs, in case something extends
in more than one unit.
C: abc FETCH 1:2 (USERSIZE)
S: *1 FETCH (12 lines)
S: *1 FETCH (57 pages 6 hours)
S: abc FETCH completed.
Servers that support USERSIZE SHOULD list the USERSIZE capability in
response to the CAPABILITY command.
4.1.3 Message length indicated as a parameter of an existing Header
Field [7].
This would be created at the source. This method would allow the
message length to be passed to the client by default.
4.1.3.1 Content-Type Header Field
Content-Type=audio/*; length=50
Content-Type=image/tiff; pages=3
4.1.3.2 Subject Header Field
Subject=Voice Message (0:04)
Subject=Fax Message (3)
The advantage of the subject field is that it is automatically
displayed to the user.
5. Media Viewer
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When a message is initially opened, the client should, by default,
open the proper media viewer to display the primary message content,
i.e. an audio player for voice messages, image viewer for fax, and
text editor for text messages.
Where there is more than one body part, obviously the appropriate
viewer should be used depending on which body part the user has
selected.
In the case where several viewers are available for a single media
type, the user should be prompted to select the desired viewer on
the first occasion that the message type is encountered. That
viewer should then become the default viewer for that media type.
The user should have the ability to change the default viewer for a
media type at any time.
5.1 Proposed Mechanism
As mentioned, the default viewer displayed to the user should be the
appropriate one for the primary message type. The client is able to
determine the primary message type from the "Primary-Content"
message header. This header is defined in the Internet Draft draft-
burger-vpim-pc-00.txt [2].
6. Mark Message as Read
Obviously, the user must be able to know which messages they have
read, and which are unread. This feature would also control the
message icon as mentioned in section 1.
With the use of multipart messages there should be a separate BODY
PART READ indicator for each body part or, at least, to only
indicate READ when the primary body part has been read. There are
two suggested methods. Favoured is method 2.
IMAP4rev1 servers that support body part read indicators SHOULD list
the keyword SEEN-BY-PART in response to the CAPABILITY command.
6.1 Proposed Mechanism
6.1.1 \SEEN per BODY PART
For example, if a client retrieves the text part of a message
without looking at the audio attachment, the indicator would show
that only the text part had been read and not the entire message.
6.1.2 \SEEN only after Primary Message Type has been opened.
Primary Message Type is discussed in VPIM Unified Message [8]. In
the case of multiple attachments the \SEEN flag would be set after
the first attachment of the primary content type has been opened.
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For example, if the primary content type is multipart/voice-message,
the \SEEN flag would be set after the first voice message is opened.
This could be the spoken name of the sender or the spoken subject as
opposed to the actual voice message.
7. Security Considerations
The desirable client behaviours described here are intended to
provide the user with a better desktop experience. However, it is
open to the same risks as any IMAP client. That is, the client is
not responsible for the format of the message received, it only
interprets. As a result, messages could be spoofed or masqueraded
to look like a message they are not to elicit a desired client
behaviour. This could be used to fool the end user, for example,
into thinking a message was a voice message (because of the icon)
when it was not.
8. References
1. Parsons, G., Vaudreuil, G., "Voice Profile for Internet Mail -
version 2", draft-ema-vpim-vpimv2r2-02.txt, October 1999
2. Burger, E., Candell, E., "Primary Content of Internet Mail",
draft-burger-vpim-pc-00.txt, Work in Progress
3. Dunne, D., "Calling Line Identification for VPIM Messages", draft-
ema-vpim-clid-00.txt, Work in Progress
4. Parsons, G., "IMAP Voice Extensions", draft-ema-vpim-imap-01.txt,
June 1999
5. Vaudreuil, G., Parsons, G., "Content Duration MIME Header
Definition", RFC2424, September 1998
6. Crispin, M., "Internet Message Access Protocol - Version 4rev1",
RFC 2060, December 1996
7. Freed, N., Borenstein, N., "Multipurpose Internet Mail Extensions
(MIME) Part One: Format of Internet Message Bodies", RFC 2045,
November 1996
8. Parsons, G., Cohen, M., Vaudreuil, G., "VPIM Unified Message MIME
Sub-Type Registration", <draft-ema-vpim-um-01.txt>, Work In Progress
9. Schulzrinne, H., Rao, A., Lanphier, R., "Real Time Streaming
Protocol (RTSP)", RFC 2326, April 1998
10. Newman, C., "IMAP URL Scheme", RFC 2192, September 1997
9 Acknowledgements
The "Proposed Mechanism" of sections 4 and 6 of this document are
borrowed from draft-ema-vpim-imap-01.txt [4]. The authors would
like to acknowledge all those who contributed to that document.
10. Author's Address
Derrick Dunne
Nortel Networks
P.O. Box 3511, Station C
Ottawa, ON
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Internet Draft Voice Messaging IMAP Client Behaviour July 2000
K1Y 4H7
Phone:+1-613-768-4087
Fax: +1-613-763-4461
Email:dunned@nortelnetworks.com
Glenn Parsons
Nortel Networks
P.O. Box 3511, Station C
Ottawa, ON
K1Y 4H7
Phone: +1-613-763-7582
Fax: +1-613-763-4461
Email: gparsons@nortelnetworks.com
11. Full Copyright Statement
Copyright (C) The Internet Society (1999). All Rights Reserved.
This document and translations of it may be copied and furnished to
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or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
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are included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
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English.
The limited permissions granted above are perpetual and will not be
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TASK FORCE DISCLAIMS 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.
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