One document matched: draft-ietf-vpim-vpimv2r2-00.txt
Network Working Group Greg Vaudreuil
Internet Draft Lucent Technologies
Expires in six months Glenn Parsons
Obsoletes: RFC 2421 Nortel Networks
July 12, 2000
Voice Profile for Internet Mail - version 2
<draft-ietf-vpim-vpimv2r2-00.txt>
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
This document is an Internet Draft. 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
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Copyright Notice
Copyright (C) The Internet Society (1999). All Rights Reserved.
Internet Draft VPIM v2 July 12, 2000
Overview
This document profiles Internet mail for voice messaging. It
obsoletes RFC 2421 which describes version 2 of the profile with less
precision. A list of changes from that document are noted in
Appendix F. As well, Appendix A summarizes the protocol profiles of
this version of VPIM.
Note: Though this draft is `00', it is a revision of the Internet
Draft issued as draft-ema-vpim-vpimv2r2-02.txt
Please send comments on this document to the IETF VPIM mailing list:
vpim@lists.neystadt.org
Additional documents and background may be found on the VPIM web page:
http://www.vpim.org
Working Group Summary
This document is a deliverable of the charter of the IETF VPIM BOF.
This document is intended as a revision of VPIM v2 [RFC 2421] for the
purposes of elevating its maturity status. No protocol changes
should be made from RFC 2421 but this document is hoped to be a more
precise profile.
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Table of Contents
1. ABSTRACT ...........................................................4
2. SCOPE ..............................................................5
2.1 Voice Messaging System Limitations................................5
2.2 Design Goals......................................................6
3. PROTOCOL RESTRICTIONS ..............................................7
4. VOICE MESSAGE INTERCHANGE FORMAT ...................................8
4.1 Message Addressing Formats........................................8
4.2 Message Header Fields............................................11
4.3 MIME Audio Content Descriptions..................................18
4.4 Voice Message Content Types......................................20
4.5 Return and Notification Messages.................................24
4.6 Forwarded Messages...............................................26
4.7 Reply Messages...................................................27
4.8 Notification Messages............................................27
5. MESSAGE TRANSPORT PROTOCOL ........................................28
5.1 ESMTP Commands...................................................28
5.2 ESMTP Keywords...................................................30
5.3 ESMTP Parameters - MAIL FROM.....................................31
5.4 ESMTP Parameters - RCPT TO.......................................32
5.5 ESMTP - SMTP Downgrading.........................................32
6. DIRECTORY ADDRESS RESOLUTION ......................................33
7. MANAGEMENT PROTOCOLS ..............................................33
7.1 Network Management...............................................33
8. CONFORMANCE REQUIREMENTS ..........................................34
9. SECURITY CONSIDERATIONS ...........................................35
9.1 General Directive................................................35
9.2 Threats and Problems.............................................35
9.3 Security Techniques..............................................36
10.REFERENCES ........................................................36
11.ACKNOWLEDGMENTS ...................................................39
12.COPYRIGHT NOTICE ..................................................39
13.AUTHORS' ADDRESSES ................................................40
14.APPENDIX A - VPIM REQUIREMENTS SUMMARY ............................41
15.APPENDIX B - EXAMPLE VOICE MESSAGES ...............................48
16.APPENDIX C - EXAMPLE ERROR VOICE PROCESSING ERROR CODES ...........53
17.APPENDIX D - EXAMPLE VOICE PROCESSING DISPOSITION TYPES ...........54
18.APPENDIX E - IANA REGISTRATIONS ...................................55
18.1 Voice Content-Disposition Parameter Definition .................55
19.APPENDIX F - CHANGE HISTORY: RFC 2421 (VPIM V2) TO THIS DOCUMENT ..56
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1. Abstract
Voice messaging evolved as telephone answering service into a full
send, receive, and forward messaging paradigm with unique message
features, semantics and usage patterns. Voice messaging was
introduced on special purpose computers that interface to a telephone
switch and provide call answering and voice messaging services.
Traditionally, messages sent from one voice messaging system to
another were transported using analog networking protocols based on
DTMF signaling and analog voice playback. As the demand for
networking increases, there was a need for a standard high-quality
digital protocol to connect these machines. VPIM has successfully
demonstrated its usefulness as this new standard. VPIM is widely
implemented and is seeing deployment in early adopter customer
networks. This document clarifies ambiguities found in the earlier
specification and is consistent with implementation practice. The
profile is referred to as VPIM (Voice Profile for Internet Mail) in
this document.
This second revision of the version 2 of obsoletes RFC 2421 that less
precisely describes version 2 of the profile.
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2. Scope
MIME is the Internet multipurpose, multimedia-messaging standard.
This document explicitly recognizes its capabilities and provides a
mechanism for the exchange of various messaging technologies,
primarily voice and facsimile.
This document specifies a restricted profile of the Internet
multimedia messaging protocols for use between voice processing
server platforms. These platforms have historically been special-
purpose computers and often do not have the same facilities normally
associated with a traditional Internet Email-capable computer. As a
result, VPIM also specifies additional functionality, as it is
needed. This profile is intended to specify the minimum common set
of features to allow interworking between compliant systems.
2.1 Voice Messaging System Limitations
The following are typical limitations of voice messaging platform
which were considered in creating this baseline profile.
1) Text messages are not normally received and often cannot be
easily displayed or viewed. They can often be processed only via
text-to-speech or text-to-fax features not currently present in
many of these machines.
2) Voice mail machines usually act as an integrated Message
Transfer Agent, Message Store and User Agent. There is typically
no relaying of messages. RFC 822 header fields may have limited use
in the context of the limited messaging features currently
deployed.
3) Voice mail message stores are generally not capable of
preserving the full semantics of an Internet message. As such, use
of a voice mail machine for gatewaying is not supported. In
particular, storage of recipient lists, "Received" lines, and
"Message-ID" may be limited.
4) Internet-style distribution/exploder mailing lists are not
typically supported. Voice mail machines often implement only
local alias lists, with error-to-sender and reply-to-sender
behavior. Reply-all capabilities using a CC list are not generally
available.
5) Error reports must be machine-parsable so that helpful responses
can be voiced to users whose only access mechanism is a telephone.
6) The voice mail systems generally limit address entry to 16 or
fewer numeric characters, and normally do not support alphanumeric
mailbox names. Alpha characters are not generally used for mailbox
identification, as they cannot be easily entered from a telephone
terminal.
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It should be noted that newer systems are based natively on SMTP/MIME
and do not suffer these limitations. In particular, some systems may
support media other than voice and fax.
2.2 Design Goals
It is a goal of this profile to make as few restrictions and
additions to the existing Internet mail protocols as possible while
satisfying the requirements for interoperability with current
generation voice messaging systems. This goal is motivated by the
desire to increase the accessibility to digital messaging by enabling
the use of proven existing networking software for rapid development.
This specification is intended for use on a TCP/IP network; however,
it is possible to use the SMTP protocol suite over other transport
protocols. The necessary protocol parameters for such use is outside
the scope of this document.
This profile is intended to be robust enough to be used in an
environment, such as the global Internet with installed-base gateways
that do not understand MIME. Full functionality, such as reliable
error messages and binary transport, will require careful selection
of gateways (e.g., via MX records) to be used as VPIM forwarding
agents. Nothing in this document precludes use of general purpose
MIME email packages to read and compose VPIM messages. While no
special configuration is required to receive VPIM compliant messages,
some may be required to originate compliant structures.
It is expected that a VPIM messaging system will be managed by a
system administrator who can perform TCP/IP network configuration.
When using facsimile or multiple voice encodings, it is suggested
that the system administrator maintain a list of the capabilities of
the networked mail machines to reduce the sending of undeliverable
messages due to lack of feature support. Configuration,
implementation and management of these directory-listing capabilities
are local matters.
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3. Protocol Restrictions
This protocol does not limit the number of recipients per message.
Where possible, server implementations should not restrict the number
of recipients in a single message. It is recognized that no
implementation supports unlimited recipients, and that the number of
supported recipients may be quite low.
This protocol does not limit the maximum message length.
Implementers should understand that some machines will be unable to
accept excessively long messages. A mechanism is defined in the RFC
1425 SMTP service extensions to declare the maximum message size
supported.
The message size indicated in the ESMTP SIZE parameter is in bytes,
not minutes or seconds. The number of bytes varies by voice encoding
format and includes the MIME wrapper overhead. If the length must be
known before sending, an approximate translation into minutes or
seconds can be performed if the voice encoding is known.
The following sections describe the restrictions and additions to
Internet mail protocols that are required to be compliant with this
VPIM v2 profile. Though various SMTP, ESMTP and MIME features are
described here, the implementer is referred to the relevant RFCs for
complete details. The table in Appendix A summarizes the protocol
details of this profile.
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 [REQ].
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4. Voice Message Interchange Format
The voice message interchange format is a profile of the Internet
Mail Protocol Suite. Any Internet Mail message containing the format
defined in this section is referred to as a VPIM Message in this
document. As a result, this document assumes an understanding of the
Internet Mail specifications. Specifically, VPIM references
components from the message format standard for Internet messages
[RFC822], the Multipurpose Internet Message Extensions [MIME], the
X.400 gateway specification [X.400], delivery status and message
disposition notifications [REPORT][DSN][DRPT][STATUS][MDN], and the
electronic business card [MIMEDIR][VCARD].
MIME, introduced in [MIME1], is a general-purpose message body format
that is extensible to carry a wide range of body parts. It provides
for encoding binary data so that it can be transported over the 7-bit
text-oriented SMTP protocol. This transport encoding (denoted by the
Content-Transfer-Encoding header field) is in addition to the audio
encoding required to generate a binary object.
MIME defines two transport-encoding mechanisms to transform binary
data into a 7-bit representation, one designed for text-like data
("Quoted-Printable"), and one for arbitrary binary data ("Base64").
While Base64 is dramatically more efficient for audio data, either
will work. Where binary transport is available, no transport
encoding is needed, and the data can be labeled as "Binary".
An implementation in compliance with this profile SHOULD send audio
and/or facsimile data in binary form when binary message transport is
available (see section 5). When binary transport is not available,
implementations MUST encode the audio and/or facsimile data as
Base64. The detection and decoding of "Quoted-Printable", "7bit",
and "8bit" MUST be supported in order to meet MIME requirements and
to preserve interoperability with the fullest range of possible
devices. However, if a content is received in a transfer encoding
that cannot be rendered to the user, an appropriate negative delivery
status notification MUST be sent.
4.1 Message Addressing Formats
RFC 822 addresses are based on the domain name system. This naming
system has two components: the local part, used for username or
mailbox identification; and the host part, used for global machine
identification.
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4.1.1 VPIM Addresses
The local part of the address shall be a US-ASCII string uniquely
identifying a mailbox on a destination system. For voice messaging,
the local part is a printable string containing the mailbox ID of the
originator or recipient. While alpha characters and long mailbox
identifiers are permitted, most voice mail networks rely on numeric
mailbox identifiers to retain compatibility with the limited 10-digit
telephone keypad. As a result, some voice messaging systems may only
be able to handle a numeric local part. The reception of
alphanumeric local parts on these systems may result in the address
being mapped to some locally unique (but confusing to the recipient)
number or, in the worst case the address could be deleted making the
message un-replyable. Additionally, it may be difficult to create
messages on these systems with an alphanumeric local part without
complex key sequences or some form of directory lookup (see 6).
The use of the domain naming system should be transparent to the
user. It is the responsibility of the voice mail machine to lookup
the fully-qualified domain name (FQDN) based on the address entered
by the user (see 6).
In the absence of a global directory, specification of the local part
is expected to conform to international or private telephone
numbering plans. It is likely that private numbering plans will
prevail and these are left for local definition. However, it is
RECOMMENDED that public telephone numbers be noted according to the
international numbering plan described in [E.164]. The indication
that the local part is a public telephone number is given by a
preceding `+' (the `+' would not be entered from a telephone keypad,
it is added by the system as a flag). Since the primary information
in the numeric scheme is contained by the digits, other character
separators (e.g. `-') may be ignored (i.e. to allow parsing of the
numeric local mailbox) or may be used to recognize distinct portions
of the telephone number (e.g. country code). The specification of
the local part of a VPIM address can be split into the four groups
described below:
1) mailbox number
- for use as a private numbering plan (any number of digits)
- e.g. 2722@lucent.com
2) mailbox number+extension
- for use as a private numbering plan with extensions
any number of digits, use of `+' as separator
- e.g. 2722+111@Lucent.com
3) +international number
- for international telephone numbers conforming to E.164
maximum of 15 digits
- e.g. +16137637582@vm.nortel.ca
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4) +international number+extension
- for international telephone numbers conforming to E.164
maximum of 15 digits, with an extension (e.g. behind a
PBX) that has a maximum of 15 digits.
- e.g. +17035245550+230@ema.org
Note that this address format is designed to be compatible with
current usage within the voice messaging industry. It is not
compatible with the addressing formats of RFC s 2303-2304. It is
expected that as telephony services become more widespread on the
Internet, these addressing formats will converge.
4.1.2 Special Addresses
Special addresses are provided for compatibility with the conventions
of Internet mail. These addresses do not use numeric local
addresses, both to conform to current Internet practice and to avoid
conflict with existing numeric addressing plans. Two special
addresses are RESERVED for use as follows:
postmaster@domain
By convention, a special mailbox named "postmaster" MUST exist on all
systems. This address is used for diagnostics and should be checked
regularly by the system manager. This mailbox is particularly likely
to receive text messages, which is not normal on a voice-processing
platform. The specific handling of these messages is an individual
implementation choice.
non-mail-user@domain
If a reply to a message is not possible, such as a telephone-
answering message, then the special address "non-mail-user" SHOULD be
used as the originator's address. Any text name such as "Telephone
Answering", or the telephone number if it is available, is permitted.
This special address is used as a token to indicate an unreachable
originator. For compatibility with the installed base of mail user
agents, implementations that generate this special address MUST send
a negative delivery status notification (DSN) for reply messages sent
to the undeliverable address. The status code for such NDN's is
5.1.1 "Mailbox does not exist".
Example:
From: Telephone Answering <non-mail-user@mycompany.com>
4.1.3 Distribution Lists
There are many ways to handle distribution list (DL) expansions and
none are 'standard'. Simple alias is a behavior closest to what most
voice mail systems do today and what is to be used with VPIM
messages. That is:
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Reply to the originator - (Address in the RFC822 Reply-to or From
field)
Errors to the submitter - (Address in the MAIL FROM: field of the
ESMTP exchange and the Return-Path:
RFC 822 field)
Some proprietary voice messaging protocols include only the recipient
of the particular copy in the envelope and include no "header fields"
except date and per-message features. Most voice messaging systems
do not provide for "Header Information" in their messaging queues and
only include delivery information. As a result, recipient
information MAY be in either the To or CC header fields. If all
recipients cannot be presented then the recipient header fields
SHOULD be omitted to indicate that an accurate list of recipients
(e.g. for use with a reply-all capability) is not known.
4.2 Message Header Fields
Internet messages contain a header information block. This header
block contains information required to identify the sender, the list
of recipients, the message send time, and other information intended
for user presentation. Except for specialized gateway and mailing
list cases, header fields do not indicate delivery options for the
transport of messages.
Distribution list processors are noted for modifying or adding to the
header fields of messages that pass through them. VPIM systems MUST
be able to accept and ignore header fields that are not defined here.
The following header lines are permitted for use with VPIM voice
messages:
4.2.1 From
SEND RULES
The originator's fully qualified domain address (a mailbox address
followed by the fully qualified domain name) MUST be present. Systems
compliant with this profile SHOULD provide the text personal name of
the voice message originator in a quoted phrase, if the name is
available. Text names of corporate or positional mailboxes MAY be
provided as a simple string. From [RFC822]
Example:
From: "Joe S. User" <12145551212@mycompany.com>
From: Technical Support <611@serviceprovider.com>
From: Non-mail-user@myserver.mycompany.com
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Voice mail machines may not be able to support separate attributes
for the "From:" and "Reply-To:" header fields and the SMTP MAIL FROM,
VPIM-conforming systems SHOULD set these values to the same address.
Use of addresses different than those present in the "From:" header
field address may result in unanticipated behavior.
RECEPTION RULES
The user listed in the from field should be presented in the voice
message envelope of the voice messaging system as the originator of
the message. The "From:" address SHOULD be used for replies (see
4.7). However, if the "From:" address contains <non-mail-
user@domain>, the user SHOULD NOT be offered the option to reply, nor
should notifications be sent to this address.
4.2.2 To
The "To:" field contains the recipient's fully-qualified domain
address. Example:
To: +12145551213@mycompany.com
SEND RULES
There MAY be one or more "To:" fields in any message. Systems SHOULD
provide a list of recipients only if all recipients are available.
Systems such as gateways from protocols which do not indicate the
complete list of recipients SHOULD provide a "To:" line. Because
these systems cannot accurately enumerate all recipients in the "To:"
headers, no recipients should be enumerated.
RECEPTION RULES
Systems compliant to this profile MAY discard the addresses in the
"To:" fields if they are unable to store the information. This
would, of course, make a reply-to-all capability impossible. If
present, the addresses in the "To:" field MAY be used for a reply
message to all recipients.
4.2.3 Cc
The "Cc:" field contains additional recipients' fully qualified
domain addresses. Many voice mail systems maintain only sufficient
envelope information for message delivery and are not capable of
storing or providing a complete list of additional recipients.
SEND RULES
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Conforming implementations MAY send "Cc:" lists if all recipients are
known at the time of origination . The list of disclosed recipients
MUST not include undisclosed recipients (ie., those sent via a blind
copy). If not, systems SHOULD omit the "Cc:" fields to indicate that
the full list of recipients is unknown or otherwise unavailable.
Example:
Cc: +12145551213@mycompany.com
RECEPTION RULES
Systems compliant to this profile MAY add all the addresses in the
"Cc:" field to the "To:" field, others MAY discard the addresses in
the "Cc:" fields. If a list of "Cc:" addresses is present, these
addresses MAY be used for a reply message to all recipients.
4.2.4 Date
The "Date:" field MUST be present and contains the date, time, and
time zone in which the message was sent by the originator.
SEND RULES
The time zone MUST be present and SHOULD be represented in a four-
digit time zone offset, such as -0500 for North American Eastern
Standard Time. This MAY be supplemented by a time zone name in
parentheses, e.g., "-0900 (PDT)". Compliant implementations SHOULD
be able to convert [RFC822] date and time stamps into local time.
If the VPIM sender is relaying a message from a system that does not
provide a time stamp, the time of arrival at the gateway system
SHOULD be used as the date.
Example:
Date: Wed, 28 Jul 96 10:08:49 -0800 (PST)
RECEPTION RULES
The sending system MUST report the time the message was sent. From
[RFC822]
4.2.5 Sender
SEND RULES
The "Sender:" field contains the actual address of the originator if
an agent on behalf of the author indicated in the "From:" field sends
the message. This header field MAY be sent by VPIM-conforming
systems.
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RECEPTION RULES
If the address in the "Sender:" field cannot be preserved in the
recipient's message queues or in the next-hop protocol from a
gateway, the field MAY be silently discarded.
4.2.6 Return-Path
The "Return-path:" field is added by the final delivering SMTP
server. If present, it contains the address from the MAIL FROM
parameter of the ESMTP exchange (see 5.1.2). Any error messages
resulting from the delivery failure MUST be sent to this address.
Note that if the "Return-path:" is null ("<>"), e.g. no path, loop
prevention or confidential, delivery status and message disposition
notifications MUST NOT be sent.
SEND RULES
The originator system MUST not add this header.
RECEPTION RULES
If the receiving system is incapable of storing the return path to be
used for subsequent delivery errors, the receiving system must
otherwise ensure that further delivery errors don't happen. Systems
that do not support the return path MUST ensure that at the time the
message is acknowledged, the message is delivered to the recipient's
ultimate mailbox. Non-Delivery notifications should not be sent
after that final delivery.
4.2.7 Message-id
The "Message-Id:" field contains a unique per-message identifier.
SEND RULES
A unique message-id MUST be generated for each message sent from a
VPIM-compliant implementation.
Example:
Message-Id: <12345678@mycompany.com>
RECEPTION RULES
The message id is not required to be stored on the receiving system.
This identifier MAY be used for tracking, auditing, and returning
receipt notification reports. From [RFC822]
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4.2.8 Reply-To
If present, the "Reply-to:" header provides a preferred address to
which reply messages should be sent (see 4.7). Typically, voice mail
systems can only support one originator of a message so it is likely
that this field will be ignored by the receiving system. From
[RFC822]
SEND RULES
A compliant system SHOULD NOT send a Reply-To header.
RECEPTION RULES
If a "reply-to:" field is present, a reply-to sender message MAY be
sent to the address specified (that is, in lieu of the address in the
"From:" field). If only one address of the originator is supported in
the message store or in the next-hop protocol from a multi-protocol
gateway, the address in the "From:" field MUST be used and the
"Reply-To:" field MAY be silently discarded.
4.2.9 Received
The "Received:" field contains trace information added to the
beginning of a RFC 822 message by MTAs. This is the only field that
may be added by an MTA. Information in this header is useful for
debugging when using an US-ASCII message reader or a header-parsing
tool. From [RFC822]
SEND RULES
A VPIM-compliant system MUST add a "Received:" field. When acting as
a gateway, information about the system translated from SHOULD be
included.
RECEPTION RULES
A VPIM-compliant system SHOULD NOT remove any "Received:" fields when
relaying messages to other MTAs or gateways. These header fields MAY
be ignored or deleted when the message is received at the final
destination.
4.2.10 MIME Version
The "MIME-Version:" field indicates that the message conforms to
[MIME]. Systems compliant with this specification SHOULD include a
comment with the words "(Voice 2.0)". [VPIM1] defines an earlier
version of this profile and uses the token (Voice 1.0). Example:
MIME-Version: 1.0 (Voice 2.0)
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This identifier is intended for information only and SHOULD NOT be
used to semantically identify the message as being a VPIM message.
Instead, the presence of the content defined in [V-MSG] SHOULD be
used if identification is necessary.
4.2.11 Content-Type
The content-type header declares the type of content enclosed in the
message. The typical top level content in a VPIM Message SHOULD be
multipart/voice-message. The allowable contents are detailed
starting in section 4.4 of this document. From [MIME2]
4.2.12 Content-Transfer-Encoding
Because Internet mail was initially specified to carry only 7-bit US-
ASCII text, it may be necessary to encode voice and fax data into a
representation suitable for that environment. The content-transfer-
encoding header describes this transformation if it is needed.
Compliant implementations MUST recognize and decode the standard
encodings, "Binary", "7bit, "8bit", "Base64" and "Quoted-Printable".
From [MIME1]
4.2.13 Sensitivity
The "Sensitivity:" field, if present, indicates the requested privacy
level. The case-insensitive values "Personal", "Private", and
"Normal" are specified. If no privacy is requested, this field is
omitted.
SEND RULES
A VPIM-compliant implementations MAY include this header to indicate
the sensitivity of a message. If the message is of "Normal"
sensitivity, this field SHOULD be omitted. From: [X.400]
RECEPTION RULES
If a "Sensitivity:" field with a value of "Personal" or "Private" is
present in the message, a compliant system MUST prohibit the
recipient from forwarding this message to any other user. A
compliant system, however, SHOULD allow the responder to reply to a
sensitive message, but SHOULD NOT include the original message
content. The responder MAY set the sensitivity of the reply message.
If the receiving system does not support privacy and the sensitivity
is one of "Personal" or "Private", a negative delivery status
notification MUST be sent to the originator with the appropriate
status code (X.Y.Z) indicating that privacy could not be assured. The
message contents SHOULD be returned to the sender to allow for a
voice context with the notification. A non-delivery notification to a
private message SHOULD NOT be tagged private since it will be sent to
the originator. From: [X.400]
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A message with no privacy explicitly noted (ie., no header) or with
_ Normal_ sensitivity has no special treatment.
4.2.14 Importance
Indicates the requested importance to be given by the receiving
system. The case-insensitive values "low", "normal" and "high" are
specified. If no special importance is requested, this header may be
omitted and the value of the absent header assumed to be "normal".
From: [X.400]
SEND RULES
Compliant implementations MAY include this header to indicate the
importance of a message
RECEPTION RULES
If the receiving system does not support importance, the attribute
may be silently dropped. If the attribute is supported, it can be
used for various user interface purposes including the ordering
messages within a mailbox or trigging notification devices such as
pagers.
4.2.15 Subject
The subject field is often provided by email systems but is not
widely supported on Voice Mail platforms. From [RFC822]
SEND RULES
For compatibility with text based mailbox interfaces, a text subject
field SHOULD be generated by a compliant implementation. It is
recommended that voice-messaging systems that do not support any text
user interfaces (e.g. access only by a telephone) insert a generic
subject header of "VPIM Message" or _ Voice Message_ for the benefit
of GUI enabled recipients.
RECEPTION RULES
It is anticipated that many voice-only systems will be incapable of
storing the subject line. The subject MAY be discarded if present by
a receiving system.
4.2.16 Disposition-Notification-To
This header MAY be present to indicate that the sender is requesting
a receipt notification from the receiving user agent. The user agent
typically sends this message disposition notification (MDN) after the
user has listened to the message and consented to an MDN being sent
Example:
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Disposition-notification-to: +12145551213@mycompany.com
SEND RULES
VPIM-compliant implementations MAY include this header to request a
disposition indication such as a listen confirmation.
RECEPTION RULES
The presence of a "Disposition-notification-to:" header in a message
is merely a request for an MDN described in 4.5.3. The recipients'
system is always free to silently ignore such a request so this
header does not burden any system that does not support it. From
[MDN].
4.2.17 Disposition-Notification-Options
This header MAY be present to define future extension parameters for
an MDN requested by the presence of the header in the previous
section.
SEND RULES
No "Disposition-notification-options:" are defined that are useful
for voice messaging. Sending systems SHOULD NOT request disposition
notification options by sending a disposition-notification-options
header.
RECEPTION RULES
Currently no parameters are defined by this document or by [MDN].
However for forward compatibility with future extensions, this header
MUST be processed if present, if MDNs are supported. If it contains
a extension parameter that is required for proper MDN generation
(noted with "=required"), then an MDN MUST NOT be sent if the
parameter is not understood. See [MDN] for complete details.
Example:
Disposition-notification-options:
whizzbang=required,foo
4.3 MIME Audio Content Descriptions
4.3.1 Content-Description:
This field MAY be present to facilitate the text identification of
these body parts in simple email readers. Any values may be used,
though it may be useful to use values similar to those for Content-
Disposition.
Example:
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Content-Description: Big Telco Voice Message
4.3.2 Content-Disposition:
This field MUST be present to allow the parsable identification of
body parts within a VPIM voice message. This is especially useful
if, as is typical, more than one Audio/* body occurs within a
single level (e.g. multipart/voice-message). Since a VPIM voice
message is intended to be automatically played upon display of the
message, in the order in which the audio contents occur, the audio
contents must always be of type inline. However, it is still
useful to include a filename value, so this should be present if
this information is available. From [DISP]
In order to distinguish between the various types of audio contents
in a VPIM voice message a new disposition parameter "voice" is
defined with the parameter values below to be used as appropriate
Voice-Message - the primary voice message,
Voice-Message-Notification - a spoken delivery notification
or spoken disposition notification,
Originator-Spoken-Name - the spoken name of the originator,
Recipient-Spoken-Name - the spoken name of the recipient(s) if
available to the originator
Spoken-Subject- the spoken subject of the message, typically
spoken by the originator
Note that there SHOULD only be one instance of each of these types
of audio contents per message level. Additional instances of a
given type (i.e., parameter value) may occur within an attached
forwarded voice message.
Implementations that do not understand the "voice" parameter (or
the Content-Disposition header) can safely ignore it, and will
present the audio bodyparts in order (but will not be able to
distinguish between them).
4.3.3 Content-Duration:
This field MAY be present to allow the specification of the length
of the audio bodypart in seconds. The use of this field on
reception is a local implementation issue. From [DUR]
Example:
Content-Duration: 33
4.3.4 Content-Language:
This field MAY be present to allow the specification of the spoken
language of the audio bodypart. The encoding is defined in [LANG].
The use of this field on reception is a local implementation issue.
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Example for UK English:
Content-Language: en-UK
4.4 Voice Message Content Types
The content types described in this section are identified for use
within the multipart/voice-message content. This content is referred
to as a `VPIM voice message' in this document and is the fundamental
part of a `VPIM message'.
Only the contents profiled subsequently (and occasionally those in
4.5) can be sent within a VPIM voice message construct (i.e., the
multipart/voice-message content type) to form a simple or a more
complex structure (several examples are given in Appendix B). The
presence of other contents within a VPIM voice message is not
permitted. Conforming implementations SHOULD NOT create a message
containing prohibited contents. In the spirit of liberal acceptance,
a conforming implementation MAY accept and render prohibited content.
unable to accept or render prohibited contents MAY discard the
contents as necessary to deliver the voice content. When multiple
contents are present within the multipart/voice-message, they SHOULD
be presented to the user in the order that they appear in the
message.
Some deployed implementations based on a common interpretation of the
original VPIM v2 specification reject messages with prohibited
content rather than discard the unsupported contents. For
interoperability with these systems, it is especially important that
prohibited contents not be sent within a multipart/voice message.
4.4.1 Multipart/Voice-Message
This MIME multipart structure provides a mechanism for packaging a
voice message into one container that is tagged as VPIM v2 compliant.
SEND RULES
The Multipart/Voice-Message content-type MUST only contain the
profiled media and content types specified in this section (i.e.
audio/*, image/*, message/rfc822 and text/directory). The most
common will be: spoken name, spoken subject, the message itself, and
an attached fax. Forwarded messages are created by simply using the
message/rfc822 construct.
Conformant implementations MUST send the multipart/voice-message in a
VPIM message. In most cases, this Multipart/Voice-Message content
will be the top level (i.e. in the Content-Type header).
RECEPTION RULES
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Conformant implementations MUST recognize the Multipart/Voice-Message
content (whether it is a top-level content or below a
multipart/mixed) and be able to separate the contents (e.g. spoken
name or spoken subject).
The semantic of multipart/Voice-Message (defined in [V-MSG]) is
identical to multipart/mixed and may be interpreted as that by
systems that do not recognize this content-type.
4.4.2 Message/RFC822
SEND RULES
MIME requires support of the Message/RFC822 message encapsulation
body part. This body part SHOULD be used within a multipart/voice-
message to forward complete messages (see 4.6) or to reply with
original content (see 4.7). From [MIME2]
RECEPTION RULES
The receiving system SHOULD treat this attachment as a forwarded
message. The receiving system may flatten the forwarding structure
(i.e., remove this construct to leave multiple voice contents or even
concatenate the voice contents to fit in a recipient's mailbox) if
necessary.
4.4.3 Text/Directory
SEND RULES
This content was profiled in the original specification of VPIM v2 as
a means of transporting contact information from the sender to the
recipient. This usage did not find widespread adoption and is no
longer a feature of VPIM V2. Conforming implementations SHOULD NOT
send the text/directory content type.
RECEPTION RULES
For compatibility with an earlier specification of VPIM v2, the
Text/Directory content type MUST be accepted by a conforming
implementation, but need not be stored, processed, or rendered to the
recipient.
4.4.4 Audio/32KADPCM
SEND RULES
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An implementation compliant to this profile MUST send Audio/32KADPCM
by default for voice [ADPCM]. This encoding is a moderately
compressed encoding with a data rate of 32 kbits/second using
moderate processing resources. Typically this body contains several
minutes of message content, however if used for spoken name or
subject the content should be considerably shorter (i.e. about 5 and
20 seconds respectively).
RECEPTION RULES
Receivers MUST be able to accept and decode Audio/32KADPCM. If an
implementation can only handle one voice body, then multiple voice
bodies (if present) SHOULD be concatenated, and SHOULD NOT be
discarded. It is RECOMMENDED that this be done in the same order as
they were sent.
4.4.5 Image/Tiff
A common image encoding for facsimile, known as TIFF-F, is a
derivative of the Tag Image File Format (TIFF) and is described in
several documents. For the purposes of VPIM, the F Profile of TIFF
for Facsimile (TIFF-F) is defined in [TIFF-F] and the image/tiff MIME
content type is defined in [TIFFREG]. While there are several
formats of TIFF, only TIFF-F is profiled for use within a VPIM voice
message. Further, since the TIFF-F file format is used in a store-
and-forward mode with VPIM, the image MUST be encoded so that there
is only one image strip per facsimile page.
SEND RULES
All VPIM implementations that support facsimile MUST generate TIFF-F
compatible facsimile contents in the image/tiff; application=faxbw
sub-type encoding by default. If the VPIM message is a voice
annotated fax, the implementation SHOULD send this fax content in
multipart/voice-message. If the message is a simple fax, an
implementation may send it without using the multipart/voice-message
to be more compatible with fax only (RFC 2305) implementations.
While any valid MIME body header MAY be used (e.g., Content-
Disposition to indicate the filename), none are specified to have
special semantics for VPIM and MAY be ignored. Note that the content
type parameter application=faxbw MUST be included in outbound
messages.
RECEPTION RULES
Inbound messages in the multipart/voice-message with or without the
application parameter MUST be rendered to the user. If the rendering
software encounters an error in the file format, some form of
negative delivery status notification SHOULD be sent to the
originator.
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Not all VPIM systems support fax, but all SHOULD accept it. Those
that do MUST support it within the multipart/voice-message and MAY
support it outside of the multipart/voice-message. Within a
multipart/voice-message, a receiving system that cannot render fax
content SHOULD accept the voice content of a VPIM message and discard
the fax content. Outside a multipart/voice-message, a recipient
system MAY reject (with appropriate NDN) the entire message if it
cannot handle the fax attachments.
Some deployed implementations based on a common interpretation of the
original VPIM V2 specification reject messages with fax content
within the multipart/voice-message rather than discard the
unsupported contents. These systems will return the message to the
sender with a NDN indicating lack of support for fax.
4.4.6 Proprietary Voice or Fax Formats
Use of any other encoding except the required codecs reduces
interoperability in the absence of explicit knowledge about the
capabilities of the recipient. A compliant implementation MAY use any
other encoding provided a unique identifier is registered with the
IANA prior to use (see [MIME4]). The voice encodings should be
registered as sub-types of Audio. The fax encodings should be
registered as sub-types of Image.
SEND RULES
Proprietary voice encoding formats or other standard formats MAY be
sent under this profile only if the sender has a reasonable
expectation that the recipient will accept the encoding. In
practice, this requires explicit per-destination configuration
information maintained either in a directory, personal address book,
or gateway configuration tables.
RECEPTION RULES
Systems MAY accept other audio/* or image/* content types if they can
decode them. Systems which receive audio/* or image/* content types
which they are unable to decode MUST return the message to the
originator with an NDN indicating media not supported.
4.4.7 Multipart/Mixed
SEND RULES
A VPIM voice message MAY be included within a message with a
multipart/mixed top level content type. Typically, this would only be
used when mixing non-voice or fax contents with a voice message.
RECEPTION RULES
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Such a message is not itself a VPIM message and the handling of such
a construct is outside the scope of the VPIM profile. However, an
the spirit of liberal acceptance, a conforming implementation MAY
accept and render a VPIM voice message contained in a
multipart/mixed.
4.4.8 Text/Plain
MIME requires support of the basic Text/Plain content type. This
content type has limited applicability within the voice-messaging
environment. However, because VPIM is a MIME profile, MIME
requirements should be met.
SEND RULES
Compliant VPIM implementations SHOULD NOT send the Text/Plain
content-type. It should be understood that the textual information is
not considered a primary media within multipart/voice-message and may
be discarded (or rejected) by a receiving system.
RECEIVE RULES
Within a multipart/voice message, the text/plain content type MAY be
dropped from the message if necessary to deliver the audio
components. The recipient SHOULD NOT reject the entire message if the
text component cannot be accepted or rendered.
Outside a Multipart/Voice-message, compliant implementations MUST
accept Text/Plain messages, however, specific handling is left as an
implementation decision. From [MIME2]
There are several mechanisms that can be used to support text (once
accepted) on voice messaging systems including text-to-speech and
text-to-fax conversions. If no rendering of the text is possible and
no indication of its presence can be given to the recipient, the
entire message MUST be returned to the sender with a negative
delivery status notification and a media-unsupported status code.
4.5 Return and Notification Messages
VPIM delivery status notification messages (4.5.2) MUST be sent to
the originator of the message when any form of non-delivery of the
subject message or its components occurs. These error messages MUST
be sent to the address in the Mail From (5.1.2) if available (same as
the return path (4.2.6) if present), otherwise, the From (4.2.1)
address may be used.
VPIM Receipt Notification messages (4.5.3) SHOULD be sent to the
sender specified in the Disposition-Notification-To header field
(4.2.16). The MDN SHOULD be sent after the message has been
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presented to the recipient or if the message has somehow been
disposed of without being presented to the recipient (e.g. if it were
deleted before playing it).
VPIM Notification messages may be positive or negative, and can
indicate delivery at the server or receipt by the client. However,
the notification MUST be contained in a multipart/report container
(4.5.1) and SHOULD contain a spoken error message.
4.5.1 Multipart/Report
The Multipart/Report is used for enclosing human-readable and machine
parsable notification (e.g. Message/delivery-status) body parts and
any returned message content. The multipart/report content-type is
used to deliver both delivery status reports indicating transport
success or failure and message disposition notifications to indicate
post-delivery events such as receipt notification.
SEND RULES
Compliant implementations MUST use the Multipart/Report construct.
From [REPORT]
Multipart/Report messages from VPIM implementations SHOULD include
the human-readable description of the error as a spoken audio/*
content (this speech MAY be made available to the notification
recipient). As well, VPIM implementations MAY generate
Multipart/Report messages that encode the human-readable description
of the error as text. Note that per [DSN] the human-readable part
MUST always be present.
RECEPTION RULES
Compliant implementations MUST recognize and decode the
Multipart/Report content type and its components in order to present
the report to the user.
As well, implementers MUST be able to handle the human readable
description of the error as text or audio.
4.5.2 Message/Delivery-status
This MIME body part is used for sending machine-parsable delivery
status notifications.
SEND RULES
Compliant implementations MUST use the Message/delivery-status
construct when returning messages or sending warnings.
RECEPTION RULES
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Compliant implementations MUST recognize and decode the
Message/delivery-status content type and present the reason for
failure to the sender of the message. From [DSN]
4.5.3 Message/Disposition-notification
This MIME body part is used for sending machine-parsable read-receipt
message disposition notifications.
SEND RULES
Conforming implementations SHOULD use the Message/Disposition-
notification construct when sending post-delivery message status
notifications. These MDNs, however, MUST only be sent in response to
the presence of the Disposition-notification-to header described in
4.2.16.
RECEPTION RULES
Conforming implementations should recognize and decode the
Message/Disposition-notification content type and present the
notification to the user. From [MDN]
4.6 Forwarded Messages
VPIM version 2 explicitly supports the forwarding of voice and fax
content with voice or fax annotation. However, only the two
constructs described below are acceptable in a VPIM message. Since
only the first (i.e. message/rfc822) can be recognized as a forwarded
message (or even multiple forwarded messages), it is RECOMMENDED that
this construct be used whenever possible.
Forwarded VPIM messages SHOULD be sent as a multipart/voice-message
with the entire original message enclosed in a message/rfc822 content
type and the annotation as a separate Audio/* or image/* body part.
If the RFC822 header fields are not available for the forwarded
content, simulated header fields with available information SHOULD be
constructed to indicate the original sending timestamp, and the
original sender as indicated in the "From" line. However, note that
at least one of "From", "Subject", or "Date" MUST be present. As
well, the message/rfc822 content MUST include at least the "MIME-
Version", and "Content-Type" header fields. From [MIME2]
In the event that forwarding information is lost, the entire audio
content MAY be sent as a single Audio/* segment without including any
forwarding semantics. An example of this loss is an AMIS message
being forwarded through an AMIS-to-VPIM gateway.
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4.7 Reply Messages
Replies to VPIM messages (and Internet mail messages) are addressed
to the address noted in the reply-to header (see 4.2.8) if it is
present, else the From address (see 4.2.1) is used.
RECEPTION RULES
Support of multiple originator header fields is often not possible on
voice messaging systems, so it may be necessary to choose only one
when gatewaying a VPIM message to another voice message system.
However, implementers should note that this may make it impossible to
send error messages and replies to their proper destinations.
In some cases, a reply message is not possible, such as with a
message created by telephone answering (i.e. classic voice mail). In
this case, the From field MUST contain the special address non-mail-
user@domain (see 4.1.2). A null ESMTP MAIL FROM address SHOULD also
be used in this case (see 5.1.2). A receiving VPIM system SHOULD NOT
offer the user the option to reply to this kind of message.
4.8 Notification Messages
VPIM delivery status notification messages (4.5.2) MUST be sent to
the originator of the message when any form of non-delivery of the
subject message or its components occurs. These error messages must
be sent to the Mail From (5.1.2) if available (same as the return
path (4.2.6) if present), otherwise, the From (4.2.1) address may be
used.
VPIM Receipt Notification messages (4.5.3) should be sent to the
sender specified in the Disposition-Notification-To header field
(4.2.16), only after the message has been presented to the recipient
or if the message has somehow been disposed of without being
presented to the recipient (e.g. if it were deleted before playing
it).
VPIM Notification messages may be positive or negative, and can
indicate delivery at the server or receipt by the client. However,
the notification MUST be contained in a multipart/report container
(4.5.1) and SHOULD contain a spoken error message.
If a VPIM system receives a message with contents that are not
understood (see 4.4), its handling is a local matter. A delivery
status notification SHOULD be generated if the message could not be
delivered because of unknown contents (e.g., on traditional voice
processing systems). In some cases, the message may be delivered
(with a positive DSN sent) to a mailbox before the determination of
rendering can be made.
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5. Message Transport Protocol
Messages are transported between voice mail machines using the
Internet Extended Simple Mail Transfer Protocol (ESMTP). All
information required for proper delivery of the message is included
in the ESMTP dialog. This information, including the sender and
recipient addresses, is commonly referred to as the message
"envelope". This information is equivalent to the message control
block in many analog voice messaging protocols.
ESMTP is a general-purpose messaging protocol, designed both to send
mail and to allow terminal console messaging. Simple Mail Transport
Protocol (SMTP) was originally created for the exchange of US-ASCII
7-bit text messages. Binary and 8-bit text messages have
traditionally been transported by encoding the messages into a 7-bit
text-like form. [ESMTP] formalized an extension mechanism for SMTP,
and subsequent RFCs have defined 8-bit text networking, command
streaming, binary networking, and extensions to permit the
declaration of message size for the efficient transmission of large
messages such as multi-minute voice mail.
The following sections list ESMTP commands, keywords, and parameters
that are required and those that are optional for conformance to this
profile.
5.1 ESMTP Commands
5.1.1 HELO
Base SMTP greeting and identification of sender.
SEND RULES
This command SHOULD not be sent by compliant systems unless the more-
capable EHLO command is not accepted. It is included for
compatibility with general SMTP implementations.
RECEPTION RULES
Compliant servers MUST implement the HELO command for backward
compatibility. From [SMTP]
5.1.2 MAIL FROM
Originating mailbox. This address contains the mailbox to which
errors should be sent.
SEND RULES
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VPIM implementations SHOULD use the same address in the MAIL FROM
command as is used in the From header field. This address is not
necessarily the same as the message Sender listed in the message
header fields if the message was received from a gateway or sent to
an Internet-style mailing list. From [SMTP, ESMTP]
RECEPTION RULES
The MAIL FROM address SHOULD be stored in the local message store for
the purposes of generating a delivery status notification to the
originator. The address indicated in the MAIL FROM command SHOULD be
passed as a local system parameter or placed in a Return-Path: line
inserted at the beginning of a VPIM message. From [HOSTREQ]
Since delivery status notifications MUST be sent to the MAIL FROM
address, the use of the null address ("<>") is often used to prevent
looping of messages. This null address MAY be used to note that a
particular message has no return path (e.g. a telephone answer
message). From [SMTP]
5.1.3 RCPT TO
The parameter to this command contains only the address to which the
message should be delivered for this transaction. It is the set of
addresses in one or more RCPT TO commands that are used for mail
routing. From [SMTP, ESMTP]
Note: In the event that multiple transport connections to multiple
destination machines are required for the same message, the set of
addresses in a given transport connection may not match the list of
recipients in the message header fields.
5.1.4 DATA
Initiates the transfer of message data. Support for this command is
required. Compliant implementations MUST implement the SMTP DATA
command for backward compatibility. From [SMTP]
5.1.5 TURN
Requests a change-of-roles, that is, the client that opened the
connection offers to assume the role of server for any mail the
remote machine may wish to send. Because SMTP is not an
authenticated protocol, the TURN command presents an opportunity to
improperly fetch mail queued for another destination. Compliant
implementations SHOULD NOT implement the TURN command. From [SMTP]
5.1.6 QUIT
Requests that the connection be closed. If accepted, the remote
machine will reset and close the connection. Compliant
implementations MUST implement the QUIT command. From [SMTP]
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5.1.7 RSET
Resets the connection to its initial state. Compliant
implementations MUST implement the RSET command. From [SMTP]
5.1.8 VRFY
Requests verification that this node can reach the listed recipient.
While this functionality is also included in the RCPT TO command,
VRFY allows the query without beginning a mail transfer transaction.
This command is useful for debugging and tracing problems. Compliant
implementations MAY implement the VRFY command. From [SMTP]
(Note that the implementation of VRFY may simplify the guessing of a
recipient's mailbox or automated sweeps for valid mailbox addresses,
resulting in a possible reduction in privacy. Various implementation
techniques may be used to reduce the threat, such as limiting the
number of queries per session.) From [SMTP]
5.1.9 EHLO
The enhanced mail greeting that enables a server to announce support
for extended messaging options. The extended messaging modes are
discussed in subsequent sections of this document. Compliant
implementations MUST implement the ESMTP command and return the
capabilities indicated later in section 5. From [ESMTP]
5.1.10 BDAT
The BDAT command provides a higher efficiency alternative to the
earlier DATA command, especially for voice. The BDAT command provides
for native binary transport of messages. Compliant implementations
SHOULD support binary transport using the BDAT command.[BINARY]
5.2 ESMTP Keywords
The following ESMTP keywords indicate extended features useful for
voice messaging.
5.2.1 PIPELINING
The "PIPELINING" keyword indicates ability of the receiving server to
accept new commands before issuing a response to the previous
command. Pipelining commands dramatically improves performance by
reducing the number of round-trip packet exchanges and makes it
possible to validate all recipient addresses in one operation.
Compliant implementations SHOULD support the command pipelining
indicated by this keyword. From [PIPE]
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5.2.2 SIZE
The "SIZE" keyword provides a mechanism by which the SMTP server can
indicate the maximum size message supported. Compliant servers MUST
provide size extension to indicate the maximum size message that can
be accepted. Clients SHOULD NOT send messages larger than the size
indicated by the server. Clients SHOULD advertise SIZE= when sending
messages to servers that indicate support for the SIZE extension.
From [SIZE]
5.2.3 CHUNKING
The "CHUNKING" keyword indicates that the receiver will support the
high-performance binary transport mode. Note that CHUNKING can be
used with any message format and does not imply support for binary
encoded messages. Compliant implementations MAY support binary
transport indicated by this capability. From [BINARY]
5.2.4 BINARYMIME
The "BINARYMIME" keyword indicates that the SMTP server can accept
binary encoded MIME messages. Compliant implementations MAY support
binary transport indicated by this capability. Note that support for
this feature requires support of CHUNKING. From [BINARY]
5.2.5 DSN
The "DSN" keyword indicates that the SMTP server will accept explicit
delivery status notification requests. Compliant implementations
MUST support the delivery notification extensions in [DRPT].
5.2.6 ENHANCEDSTATUSCODES
The "ENHANCEDSTATUSCODES" keyword indicates that an SMTP server
augments its responses with the enhanced mail system status codes
[CODES]. These codes can then be used to provide more informative
explanations of error conditions, especially in the context of the
delivery status notification format defined in [DSN]. Compliant
implementations SHOULD support this capability. From [STATUS]
5.3 ESMTP Parameters - MAIL FROM
5.3.1 BINARYMIME
The current message is a binary encoded MIME messages. Compliant
implementations SHOULD support binary transport indicated by this
parameter. From [BINARY]
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5.3.2 RET
The RET parameter indicates whether the content of the message should
be returned. Compliant systems SHOULD honor a request for returned
content. From [DRPT]
5.3.3 ENVID
The ENVID keyword of the SMTP MAIL command is used to specify an
"envelope identifier" to be transmitted along with the message and
included in any DSNs issued for any of the recipients named in this
SMTP transaction. The purpose of the envelope identifier is to allow
the sender of a message to identify the transaction for which the DSN
was issued. Compliant implementations MAY use this parameter. From
[DRPT]
5.4 ESMTP Parameters - RCPT TO
5.4.1 NOTIFY
The NOTIFY parameter indicates the conditions under which a delivery
report should be sent. Compliant implementations MUST honor this
request. From [DRPT]
5.4.2 ORCPT
The ORCPT keyword of the RCPT command is used to specify an
"original" recipient address that corresponds to the actual recipient
to which the message is to be delivered. If the ORCPT esmtp-keyword
is used, it MUST have an associated esmtp-value, which consists of
the original recipient address. Compliant implementations MAY use
this parameter. From [DRPT]
5.5 ESMTP - SMTP Downgrading
The ESMTP extensions suggested or required for conformance to VPIM
fall into two categories. The first category includes features that
increase the efficiency of the transport system such as SIZE,
BINARYMIME, and PIPELINING. In the event of a downgrade to a less
functional transport system, these features can be dropped with no
functional change to the sender or recipient.
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The second category of features is transport extensions in support of
new functions. DSN and EnhancedStatusCodes provide essential
improvements in the handling of delivery status notifications to
bring email to the level of reliability expected of Voice Mail. To
ensure a consistent level of service across an intranet or the global
Internet, it is essential that VPIM compliant ESMTP support the ESMTP
DSN extension at all hops between a VPIM originating system and the
recipient system. In the situation where a `downgrade' is unavoidable
a relay hop may be forced (by the next hop) to forward a VPIM message
without the ESMTP request for positive delivery status notification.
It is RECOMMENDED that the downgrading system should continue to
attempt to deliver the message, but MUST send an appropriate delivery
notification to the originator, e.g. the message left an ESMTP host
and was sent (unreliably) via SMTP.
6. Directory Address Resolution
It is the responsibility of a VPIM system to provide the fully-
qualified domain name (FQDN) of the recipient based on the address
entered by the user (if the entered address is not already a FQDN).
This would typically be an issue on systems that offered only a
telephone user interface. The mapping of the dialed target number to
a routable FQDN address allowing delivery to the destination system
can be accomplished through implementation-specific means.
To facilitate a local cache, an implementation may wish to populate
local directories with the first and last names, as well as the
senders spoken name information extracted from received messages.
Addresses or names parsed from the header fields of VPIM messages MAY
be used to populate directories.
7. Management Protocols
The Internet protocols provide a mechanism for the management of
messaging systems, from the management of the physical network
through the management of the message queues. SNMP should be
supported on a compliant message machine.
7.1 Network Management
The digital interface to the VM and the TCP/IP protocols MAY be
managed. MIB II MAY be implemented to provide basic statistics and
reporting of TCP and IP protocol performance. [MIB II]
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8. Conformance Requirements
VPIM is a messaging application that must be supported in several
environments and be supported on differing devices. These
environments include traditional voice processing systems, desktop
voice messaging systems, store and forward relays, and protocol
translation gateways.
In order to accommodate all environments, this document defines two
areas of conformance: transport and content.
Transport conformant systems will pass VPIM messages in a store and
forward manner with assured delivery notifications and without the
loss of information. It is expected that most store and forward
Internet mail based messaging systems will be VPIM transport
compliant.
Content conformant systems will generate and interpret VPIM messages.
Conformance in the generation of VPIM messages indicates that the
restrictions of this profile are honored. Only contents specified in
this profile or extensions agreed to by bilateral agreement may be
sent. Conformance in the interpretation of VPIM messages indicates
that all VPIM content types and constructs can be received; that all
mandatory VPIM content types can be decoded and presented to the
recipient in an appropriate manner; and that any unrenderable
contents result in the appropriate notification.
A summary of the compliance requirements is contained in Appendix A.
VPIM end systems are expected to be both transport and content
conformant. They should generate conforming content, reliably send
it to the next hop system, receive a message, decode the message and
present it to the user. Voice messaging systems and protocol
conversion gateways are considered end systems.
Relay systems are expected to be transport compliant in order to
receive and send conforming messages. However, they must also create
VPIM conforming delivery status notifications in the event of
delivery problems.
Desktop Email clients that support VPIM and are expected to be
content conformant. Desktop email clients use various protocols and
API's for exchanging messages with the local message store and
message transport system. While these clients may benefit from VPIM
transport capabilities, specific client-server requirements are out-
of-scope for this document.
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9. Security Considerations
9.1 General Directive
This document is a profile of existing Internet mail protocols. To
maintain interoperability with Internet mail, any security to be
provided should be part of the Internet security infrastructure,
rather than a new mechanism or some other mechanism outside of the
Internet infrastructure.
9.2 Threats and Problems
Both Internet mail and voice messaging have their own set of threats
and countermeasures. As such, this specification does not create any
security issues not already existing in the profiled Internet mail
and voice mail protocols themselves. This section attends only to
the set of additional threats that ensue from integrating the two
services.
9.2.1 Spoofed sender
The actual sender of the voice message might not be the same as that
specified in the Sender or From header fields of the message content
header fields or the MAIL FROM address from the SMTP envelope. In a
tightly constrained environment, sufficient physical and software
controls may be able to ensure prevention of this problem. In
addition, the recognition of the sender's voice may provide
confidence of the sender's identity irrespective of that specified in
Sender or From. It should be recognized that SMTP implementations do
not provide inherent authentication of the senders of messages, nor
are sites under obligation to provide such authentication.
9.2.2 Unsolicited voice mail
Assigning an Internet mail address to a voice mailbox opens the
possibility of receiving unsolicited messages (either text or voice
mail). Traditionally voice mail systems operated in closed
environments and were not susceptible to unknown senders. Voice mail
users have a higher expectation of mailbox privacy and may consider
such messages as a security breach. Many Internet mail systems are
choosing to block all messages from unknown sources in an attempt to
curb this problem.
9.2.3 Message disclosure
Users of voice messaging systems have an expectation of a level of
message privacy that is higher than the level provided by Internet
mail without security enhancements. This expectation of privacy by
users SHOULD be preserved as much as possible.
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9.3 Security Techniques
Sufficient physical and software control may be acceptable in
constrained environments. Further, the profile specified in this
document does not in any way preclude the use of any Internet object
or channel security protocol to encrypt, authenticate, or non-
repudiate the messages.
10. References
[8BIT] Klensin, J., Freed, N., Rose, M., Stefferud, E., D. Crocker,
"SMTP Service Extension for 8bit-MIMEtransport" RFC 1426, United
Nations University, Innosoft International, Inc., Dover Beach
Consulting, Inc., Network Management Associates, Inc., The Branch
Office, February 1993.
[ADPCM] G. Vaudreuil and G. Parsons, "Toll Quality Voice - 32 kbit/s
ADPCM: MIME Sub-type Registration", RFC 2422, September 1998.
[AMIS-A] Audio Messaging Interchange Specifications (AMIS) - Analog
Protocol Version 1, Issue 2, February 1992.
[AMIS-D] Audio Messaging Interchange Specifications (AMIS) - Digital
Protocol Version 1, Issue 3 August 1993.
[BINARY] Vaudreuil, G., "SMTP Service Extensions for Transmission of
Large and Binary MIME Messages", RFC 1830, October 1995.
[CODES] Vaudreuil, G. "Enhanced Mail System Status Codes", RFC 1893,
01/15/1996.
[MIMEDIR] F. Dawson, T. Howes, & M. Smith, "A MIME Content-Type for
Directory Information", RFC 2425 September 1998
[DISP] R. Troost and S. Dorner, Communicating Presentation Information
in Internet Messages: The Content-Disposition Header, RFC 2183,
August 1997
[DNS1] Mockapetris, P., "Domain names - implementation and
specification", RFC1035, Nov 1987.
[DNS2] Mockapetris, P., "Domain names - concepts and facilities", RFC
1034, Nov 1987.
[DRPT] Moore, K. "SMTP Service Extensions for Delivery Status
Notifications", RFC 1891, 01/15/1996
[DSN] Moore, K., Vaudreuil, G., "An Extensible Message Format for
Delivery Status Notifications", RFC 1894, 01/15/1996.
[DUR] G. Parsons and G. Vaudreuil, "Content Duration MIME Header
Definition", RFC 2424, September 1998.
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[E164] CCITT Recommendation E.164 (1991), Telephone Network and ISDN
Operation, Numbering, Routing and Mobile Service - Numbering Plan
for the ISDN Era.
[ESMTP] Klensin, J., Freed, N., Rose, M., Stefferud, E., and D. Crocker,
"SMTP Service Extensions" RFC 1869, United Nations University,
Innosoft International, Inc., Dover Beach Consulting, Inc., Network
Management Associates, Inc., The Branch Office, November 1995.
[G726] CCITT Recommendation G.726 (1990), General Aspects of Digital
Transmission Systems, Terminal Equipment - 40, 32, 24,16 kbit/s
Adaptive Differential Pulse Code Modulation (ADPCM).
[HOSTREQ] Braden, R., "Requirements for Internet Hosts -- Application
and Support", STD 3, RFC 1123, October 1989.
[LANG] Alvestrand,H., "Tags for the Identification of Languages", RFC
1766, Mar 1995
[MDN] Fajman, Roger, "An Extensible Message Format for Message
Disposition Notifications" RFC 2298, March 1998
[MIB II] M. Rose, "Management Information Base for Network Management of
TCP/IP-based internets: MIB-II", RFC 1158, May 1990.
[MIME1] N. Freed and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message Bodies", RFC
2045, Innosoft, First Virtual, Nov 1996.
[MIME2] N. Freed and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types ", RFC 2046, Innosoft, First
Virtual, Nov 1996.
[MIME3] K. Moore, "Multipurpose Internet Mail Extensions (MIME) Part
Three: Message Header Extensions for Non-ASCII Text ", RFC 2047,
University of Tennessee, Nov 1996.
[MIME4] N. Freed, J. Klensin and J. Postel, "Multipurpose Internet Mail
Extensions (MIME) Part Four: Registration Procedures", RFC 2048,
Innosoft, MCI, ISI, Nov 1996.
[MIME5] N. Freed and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Five: Conformance Criteria and Examples ",
RFC 2049, Innosoft, First Virtual, Nov 1996.
[PIPE] Freed, N., Cargille, A., "SMTP Service Extension for Command
Pipelining" RFC 1854, October 1995.
[REPORT] Vaudreuil, G., "The Multipart/Report Content Type for the
Reporting of Mail System Administrative Messages", RFC 1892,
01/15/1996.
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[REQ] S. Bradner, "Key words for use in RFCs to Indicate Requirement
Levels", RFC 2119, March 1997.
[RFC822] Crocker, D., "Standard for the Format of ARPA Internet Text
Messages", STD 11, RFC 822, UDEL, August 1982.
[SIZE] Klensin, J, Freed, N., Moore, K, "SMTP Service Extensions for
Message Size Declaration" RFC 1870, United Nations University,
Innosoft International, Inc., November 1995.
[SMTP] Postel, J., "Simple Mail Transfer Protocol", STD 10, RFC 821,
USC/Information Sciences Institute, August 1982.
[STATUS] Freed, N. "SMTP Service Extension for Returning Enhanced Error
Codes", RFC 2034, 10/30/1996.
[TIFF-F] G. Parsons and J. Rafferty, "Tag Image File Format:
Application F", RFC 2306 , March 1998.
[TIFFREG] G. Parsons, J. Rafferty & S. Zilles, "Tag Image File Format:
image/tiff - MIME sub-type registraion", RFC 2302, March 1998.
[V-MSG] G. Vaudreuil and G. Parsons, "VPIM Voice Message MIME Sub-type
Registration", RFC 2423, September 1998.
[VCARD] Dawson, Frank, Howes, Tim, "vCard MIME Directory Profile" RFC
2426, September 1998.
[VPIM1] Vaudreuil, Greg, "Voice Profile for Internet Mail", RFC 1911,
Feb 1996.
[VPIM2] Vaudreuil, Greg, Parsons, Glenn, "Voice Profile for Internet
Mail, Version 2", RFC 2421, September 1998.
[X.400] CCITT/ISO, "CCITT Recommendations X.400/ ISO/IEC 10021-1,
Message Handling: System and Service Overview", Dec 1988.
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11. Acknowledgments
The authors would like to offer a special thanks to the Electronic
Messaging Association (EMA), especially the members of the Voice
Messaging Committee and the VPIM Work Group, for their support of the
VPIM specification and the efforts they have made to ensure its
success.
The EMA hosts the VPIM web page at http://www.ema.org/vpim.
12. Copyright Notice
"Copyright (C) The Internet Society (2000). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
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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13. Authors' Addresses
Glenn W. Parsons
Nortel Networks
P.O. Box 3511, Station C
Ottawa, ON K1Y 4H7
Canada
Phone: +1-613-763-7582
Fax: +1-613-763-4461
GParsons@NortelNetworks.com
Gregory M. Vaudreuil
Lucent Technologies
7291 Williamson Rd
Dallas, TX 75214
United States
Phone/Fax: +1-972-733-2722
GregV@ieee.org
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14. Appendix A - VPIM Requirements Summary
The following table summarizes the profile of VPIM version 2 detailed
in this document. Since in many cases it is not possible to simplify
the qualifications for supporting each feature this appendix is
informative. The reader is recommended to read the complete
explanation of each feature in the referenced section. The text in
the previous sections shall be deemed authoritative if any item in
this table is ambiguous.
The conformance table is separated into various columns:
Feature - name of protocol feature (note that the indenting
indicates a hierarchy of conformance, i.e. the
conformance of a lower feature is only relevant if there
is conformance to the higher feature)
Section - reference section in main text of this document
Area - conformance area to which each feature applies:
C - content
T - transport
Status - whether the feature is mandatory, optional, or prohibited.
The key words used in this table are to be interpreted as described
in [REQ], though the following list gives a quick overview of the
different degrees of feature conformance:
Must - mandatory
Should - required in the absence of a compelling
need to omit.
May - optional
Should not - prohibited in the absence of a compelling
need.
Must not - prohibited
Footnote - special comment about conformance for a particular
feature
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VPIM version 2 Conformance
| | | | |S| |
| | | | | |H| |F
| | | | | |O|M|o
| | | |S| |U|U|o
| | | |H| |L|S|t
| |A|M|O| |D|T|n
| |R|U|U|M| | |o
| |E|S|L|A|N|N|t
| |A|T|D|Y|O|O|t
FEATURE |SECTION | | | | |T|T|e
-------------------------------------------|----------|-|-|-|-|-|-|-
| | | | | | | |
Message Addressing Formats: | | | | | | | |
Use DNS host names |4.1 |C|x| | | | |
Use only numbers in mailbox IDs |4.1.1 |C| |x| | | |
Use alpha-numeric mailbox IDs |4.1.1 |C| | |x| | |
Support of postmaster@domain |4.1.2 |C|x| | | | |
Support of non-mail-user@domain |4.1.2 |C| |x| | | |
Support of distribution lists |4.1.3 |C| |x| | | |
| | | | | | | |
Message Header Fields: | | | | | | | |
Encoding outbound messages | | | | | | | |
From |4.2.1 |C|x| | | | |
Addition of text name |4.2.1 |C| |x| | | |
To |4.2.2 |C| |x| | | |1
cc |4.2.3 |C| |x| | | |1
Date |4.2.4 |C|x| | | | |
Sender |4.2.5 |C| | |x| | |
Return-Path |4.2.6 |C| | | |x| |
Message-id |4.2.7 |C|x| | | | |
Reply-To |4.2.8 |C| | | |x| |
Received |4.2.9 |C|x| | | | |
MIME Version: 1.0 (Voice 2.0) |4.2.10 |C| |x| | | |
Content-Type |4.2.11 |C|x| | | | |
Content-Transfer-Encoding |4.2.12 |C|x| | | | |
Sensitivity |4.2.13 |C| | |x| | |
Importance |4.2.14 |C| | |x| | |
Subject |4.2.15 |C| |x| | | |
Disposition-notification-to |4.2.16 |C| | |x| | |
Disposition-notification-options |4.2.17 |C| | |x| | |
Other Headers |4.2 |C| | |x| | |
| | | | | | | |
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| | | | |S| |
| | | | | |H| |F
| | | | | |O|M|o
| | | |S| |U|U|o
| | | |H| |L|S|t
| |A|M|O| |D|T|n
| |R|U|U|M| | |o
| |E|S|L|A|N|N|t
| |A|T|D|Y|O|O|t
FEATURE |SECTION | | | | |T|T|e
-------------------------------------------|----------|-|-|-|-|-|-|-
Detection & Decoding inbound messages | | | | | | | |
From |4.2.1 |C|x| | | | |
Present text personal name |4.2.1 |C| | |x| | |
To |4.2.2 |C|x| | | | |
cc |4.2.3 |C| | |x| | |
Date |4.2.4 |C|x| | | | |
Conversion of Date to local time |4.2.4 |C| |x| | | |
Sender |4.2.5 |C| | |x| | |
Return-Path |4.2.6 |C| |x| | | |
Message ID |4.2.7 |C|x| | | | |
Reply-To |4.2.8 |C| | |x| | |
Received |4.2.9 |C| | |x| | |
MIME Version: 1.0 (Voice 2.0) |4.2.10 |C| |x| | | |
Content Type |4.2.11 |C|x| | | | |
Content-Transfer-Encoding |4.2.12 |C|x| | | | |
Sensitivity |4.2.13 |C|x| | | | |2
Importance |4.2.14 |C| | |x| | |
Subject |4.2.15 |C| | |x| | |
Disposition-notification-to |4.2.16 |C| | |x| | |
Disposition-notification-options |4.2.17 |C| | | |x| |
Other Headers |4.2 |C|x| | | | |3
| | | | | | | |
Message Content Encoding: | | | | | | | |
Encoding outbound audio/fax contents | | | | | | | |
7BIT |4 |C| | | | |x|
8BIT |4 |C| | | | |x|
Quoted Printable |4 |C| | | | |x|
Base64 |4 |C|x| | | | |4
Binary |4 |C| |x| | | |5
Detection & decoding inbound messages | | | | | | | |
7BIT |4 |C|x| | | | |
8BIT |4 |C|x| | | | |
Quoted Printable |4 |C|x| | | | |
Base64 |4 |C|x| | | | |
Binary |4 |C|x| | | | |5
| | | | | | | |
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| | | | | |H| |F
| | | | | |O|M|o
| | | |S| |U|U|o
| | | |H| |L|S|t
| |A|M|O| |D|T|n
| |R|U|U|M| | |o
| |E|S|L|A|N|N|t
| |A|T|D|Y|O|O|t
FEATURE |SECTION | | | | |T|T|e
-------------------------------------------|----------|-|-|-|-|-|-|-
Message Content Types: | | | | | | | |
Inclusion in outbound messages | | | | | | | |
Multipart/Voice-Message |4.4.1 |C|x| | | | |
Message/RFC822 |4.4.2 |C| | |x| | |
Audio/32KADPCM |4.4.4 |C|x| | | | |
Content-Description |4.3.1 |C| | |x| | |
Content-Disposition |4.3.2 |C|x| | | | |
Content-Duration |4.3.3 |C| | |x| | |
Content-Language |4.3.4 |C| | |x| | |
Image/tiff; application=faxbw |4.4.5 |C| | |x| | |
Audio/* or Image/* (other encodings) |4.4.6 |C| | |x| | |
Other contents |4.4 |C| | | | |x|
Multipart/Mixed |4.4.7 |C| | |x| | |
Text/plain |4.4.8 |C| | | |x| |
Multipart/Report |4.5.1 |C|x| | | | |
human-readable part is voice |4.5.1 |C| |x| | | |
human-readable part is text |4.5.1 |C| | |x| | |
Message/delivery-status |4.5.2 |C|x| | | | |
Message/disposition-notification |4.5.3 |C| |x| | | |
Other contents |4.4 |C| | |x| | |6
| | | | | | | |
Detection & decoding in inbound messages | | | | | | | |
Multipart/Voice-Message |4.4.1 |C|x| | | | |
Message/RFC822 |4.4.2 |C|x| | | | |
Text/Directory |4.4.3 |C|x| | | | |
Audio/32KADPCM |4.4.4 |C|x| | | | |
Content-Description |4.3.1 |C| | |x| | |
Content-Disposition |4.3.2 |C| |x| | | |
Content-Duration |4.3.3 |C| | |x| | |
Content-Langauge |4.3.4 |C| | |x| | |
Image/tiff; application=faxbw |4.4.5 |C| |x| | | |7
Audio/* or Image/* (other encodings) |4.4.6 |C| | |x| | |
Other contents |4.4 |C| | | |x| |
Multipart/Mixed |4.4.7 |C|x| | | | |
Text/plain |4.4.8 |C|x| | | | |
send NDN if unable to render |4.4.8 |C|x| | | | |
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| | | | | |H| |F
| | | | | |O|M|o
| | | |S| |U|U|o
| | | |H| |L|S|t
| |A|M|O| |D|T|n
| |R|U|U|M| | |o
| |E|S|L|A|N|N|t
| |A|T|D|Y|O|O|t
FEATURE |SECTION | | | | |T|T|e
------------------------------------------|-----------|-|-|-|-|-|-|-
| | | | | | | |
Multipart/Report |4.5.1 |C|x| | | | |
human-readable part is voice |4.5.1 |C| |x| | | |
human-readable part is text |4.5.1 |C|x| | | | |
Message/delivery-status |4.5.2 |C|x| | | | |
Message/disposition-notification |4.5.3 |C| |x| | | |
Other contents |4.4 |C| | |x| | |6
send NDN if unable to render |4.4 |C| |x| | | |
| | | | | | | |
Forwarded Messages | | | | | | | |
use Message/RFC822 construct |4.6 |C| |x| | | |
simulate headers if none available |4.6 |C| |x| | | |
| | | | | | | |
Reply Messages | | | | | | | |
send to Reply-to, else From address |4.7 |C|x| | | | |
send to non-mail-user |4.7 |C| | | |x| |
| | | | | | | |
Notifications | | | | | | | |
use multipart/report format |4.8 |C|x| | | | |
always send error on non-delivery |4.8 |C| |x| | | |
| | | | | | | |
Message Transport Protocol: | | | | | | | |
ESMTP Commands | | | | | | | |
HELO |5.1.1 |T|x| | | | |
MAIL FROM |5.1.2 |T|x| | | | |
support null address |5.1.2 |T|x| | | | |
RCPT TO |5.1.3 |T|x| | | | |
DATA |5.1.4 |T|x| | | | |
TURN |5.1.5 |T| | | | |x|
QUIT |5.1.6 |T|x| | | | |
RSET |5.1.7 |T|x| | | | |
VRFY |5.1.8 |T| | |x| | |
EHLO |5.1.9 |T|x| | | | |
BDAT |5.1.10 |T| | |x| | |5
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| | | | |S| |
| | | | | |H| |F
| | | | | |O|M|o
| | | |S| |U|U|o
| | | |H| |L|S|t
| |A|M|O| |D|T|n
| |R|U|U|M| | |o
| |E|S|L|A|N|N|t
| |A|T|D|Y|O|O|t
FEATURE |SECTION | | | | |T|T|e
-------------------------------------------|----------|-|-|-|-|-|-|-
| | | | | | | |
ESMTP Keywords & Parameters | | | | | | | |
PIPELINING |5.2.1 |T| |x| | | |
SIZE |5.2.2 |T|x| | | | |
CHUNKING |5.2.3 |T| | |x| | |
BINARYMIME |5.2.4,5.3.1|T| | |x| | |
DSN |5.2.5 |T|x| | | | |
ENHANCEDSTATUSCODES |5.2.6 |T| |x| | | |
RET |5.3.2 |T| |x| | | |
ENVID |5.3.3 |T| | |x| | |
NOTIFY |5.4.1 |T|x| | | | |
ORCPT |5.4.2 |T| | |x| | |
| | | | | | | |
ESMTP-SMTP Downgrading | | | | | | | |
send delivery report upon downgrade |5.5 |T|x| | | | |
| | | | | | | |
Directory Address Resolution | | | | | | | |
provide facility to resolve addresses |6 |C| |x| | | |
use headers to populate local directory |6 |C| | |x| | |
| | | | | | | |
Management Protocols: | | | | | | | |
Network management |7.1 |T| | |x| | |
-------------------------------------------|----------|-|-|-|-|-|-|-
Footnotes:
1. SHOULD leave blank if all recipients are not known or resolvable.
2. If a sensitive message is received by a system that does not
support sensitivity, then it MUST be returned to the originator
with an appropriate error notification. Also, a received
sensitive message MUST NOT be forwarded to anyone.
3. If the additional header fields are not understood they MAY be
ignored
4. When binary transport is not available
5. When binary transport is available
6. Other un-profiled contents must only be sent by bilateral
agreement.
7. If the content cannot be presented or acknowledged in some form,
the entire message MUST be returned with a negative delivery
status notification.
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8. When the vCard is present in a message
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15. Appendix B - Example Voice Messages
The following message is a full-featured message addressed to two
recipients. The message includes the sender's spoken name, spoken
subject and a short speech segment. The message is marked as
important and private.
To: +19725551212@vm1.mycompany.com
To: +16135551234@VM1.mycompany.com
From: "Parsons, Glenn" <12145551234@VM2.mycompany.com>
Date: Mon, 26 Aug 93 10:20:20 -0700 (CDT)
MIME-Version: 1.0 (Voice 2.0)
Content-type: Multipart/Voice-Message; Version=2.0;
Boundary="MessageBoundary"
Content-Transfer-Encoding: 7bit
Message-ID: 123456789@VM2.mycompany.com
Sensitivity: Private
Importance: High
--MessageBoundary
Content-type: Audio/32KADPCM
Content-Transfer-Encoding: Base64
Content-Disposition: inline; voice=Originator-Spoken-Name
Content-Language: en-US
Content-ID: part1@VM2-4321
glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
(This is a sample of the base-64 Spoken Name data)
fgdhgddlkgpokpeowrit09==
--MessageBoundary
Content-type: Audio/32KADPCM
Content-Transfer-Encoding: Base64
Content-Disposition: inline; voice=Spoken-Subject
Content-Language: en-US
Content-ID: part2@VM2-4321
glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
(This is a sample of the base-64 Spoken Subject data)
fgdhgddlkgpokpeowrit09==
--MessageBoundary
Content-type: Audio/32KADPCM
Content-Transfer-Encoding: Base64
Content-Description: Brand X Voice Message
Content-Disposition: inline; voice=Voice-Message; filename=msg1.726
Content-Duration: 25
iIiIiIjMzN3czdze3s7d7fwfHhcvESJVe/4yEhLz8/FOQjVFRERCESL/zqrq
(This is a sample of the base64 message data) zb8tFdLTQt1PXj
u7wjOyRhws+krdns7Rju0t4tLF7cE0K0MxOTOnRW/Pn30c8uHi9==
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--MessageBoundary_
The following message is a forwarded single segment voice. Both the
forwarded message and the forwarding message contain the senders
spoken names.
To: +12145551212@vm1.mycompany.com
From: "Vaudreuil, Greg" <+19725552345@VM2.mycompany.com>
Date: Mon, 26 Aug 93 10:20:20 -0700 (CDT)
MIME-Version: 1.0 (Voice 2.0)
Content-type: Multipart/Voice-Message; Version=2.0;
Boundary="MessageBoundary"
Content-Transfer-Encoding: 7bit
Message-ID: ABCD-123456789@VM2.mycompany.com
--MessageBoundary
Content-type: Audio/32KADPCM
Content-Transfer-Encoding: Base64
Content-Disposition: inline; voice=Originator-Spoken-Name
Content-Language: en-US
Content-ID: part3@VM2-4321
glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
(This is a sample of the base-64 Spoken Name data)
fgdhgd dlkgpokpeowrit09==
--MessageBoundary
Content-type: Audio/32KADPCM
Content-Description: Forwarded Message Annotation
Content-Disposition: inline; voice=Voice-Message
Content-Transfer-Encoding: Base64
glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
(This is the voiced introductory remarks encoded in base64)
jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gQ5tkjpokfgW
dlkgpokpeowrit09==
--MessageBoundary
Content-type: Message/RFC822
Content-Transfer-Encoding: 7bit
To: +19725552345@VM2.mycompany.com
From: "Parsons, Glenn, W." <+16135551234@VM1.mycompany.com>
Date: Mon, 26 Aug 93 8:23:10 -0500 (EST)
Content-type: Multipart/Voice-Message; Version=2.0;
Boundary="MessageBoundary2"
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0 (Voice 2.0)
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--MessageBoundary2
Content-type: Audio/32KADPCM
Content-Transfer-Encoding: Base64
Content-Disposition: inline; voice=Originator-Spoken-Name
Content-Language: en-US
Content-ID: part6@VM2-4321
glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
(This is a sample of the base-64 Spoken Name data) fgdhgd
dlkgpokpeowrit09==
--MessageBoundary2
Content-type: Audio/32KADPCM
Content-Disposition: inline; voice=Voice-Message
Content-Transfer-Encoding: Base64
glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
(This is the original message audio data) fgwersdfmniwrjj
jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gQ5tkjpokfgW
dlkgpokpeowrit09==
--MessageBoundary2--
--MessageBoundary--
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The following example is for a message returned to the sender by a
VPIM gateway at VM1.company.com for a mailbox which does not exist.
Date: Thu, 7 Jul 1994 17:16:05 -0400
From: Mail Delivery Subsystem <MAILER-DAEMON@vm.company.com>
Message-Id: <199407072116.RAA14128@vm1.company.com>
Subject: Returned voice message
To: 2175552345@VM2.mycompany.com
MIME-Version: 1.0 (Voice 2.0)
Content-Type: multipart/report; report-type=delivery-status;
boundary="RAA14128.773615765/VM1.COMPANY.COM"
--RAA14128.773615765/VM1.COMPANY.COM
Content-type: Audio/32KADPCM
Content-Description: Spoken Delivery Status Notification
Content-Disposition: inline; voice= Voice-Message-Notification
Content-Transfer-Encoding: Base64
glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadadffsssddasdasd
(This is a voiced description of the error in base64)
jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gdffkjpokfgW
dlkgpokpeowrit09==
--RAA14128.773615765/VM1.COMPANY.COM
Content-type: message/delivery-status
Reporting-MTA: dns; vm1.company.com
Original-Recipient: rfc822; 2145551234@VM1.mycompany.com
Final-Recipient: rfc822; 2145551234@VM1.mycompany.com
Action: failed
Status: 5.1.1 (User does not exist)
Diagnostic-Code: smtp; 550 Mailbox not found
Last-Attempt-Date: Thu, 7 Jul 1994 17:15:49 -0400
--RAA14128.773615765/VM1.COMPANY.COM
content-type: message/rfc822
[original VPIM message goes here]
--RAA14128.773615765/VM1.COMPANY.COM--
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The following example is for a receipt notification sent to the
original sender for a message which has been played. This
delivered VPIM message was received by a corporate gateway and
relayed to a unified mailbox.
Date: Thu, 7 Jul 1994 17:16:05 -0400
From: "Greg Vaudreuil" <22722@vm.company.com>
Message-Id: <199407072116.RAA14128@exchange.company.com>
Subject: Voice message played
To: 2175552345@VM2.mycompany.com
MIME-Version: 1.0 (Voice 2.0)
Content-Type: multipart/report;
Report-type=disposition-notification;
Boundary="RAA14128.773615765/EXCHANGE.COMPANY.COM"
--RAA14128.773615765/EXCHANGE.COMPANY.COM
Content-type: Audio/32KADPCM
Content-Description: Spoken Disposition Notification
Content-Disposition: inline; voice= Voice-Message-Notification
Content-Transfer-Encoding: Base64
glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadadffsssddasdasd
(Voiced description of the disposition action in base64)
jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gdffkjpokfgW
dlkgpokpeowrit09==
--RAA14128.773615765/EXCHANGE.COMPANY.COM
Content-type: message/disposition-notification
Reporting-UA: gregs-laptop.dallas.company.com (Unified FooMail 3.0)
Original-Recipient: rfc822;22722@vm.company.com
Final-Recipient: rfc822;Greg.Vaudreuil@foomail.company.com
Original-Message-ID: <199509192301.12345@vm2.mycompany.com >
Disposition: manual-action/MDN-sent-automatically; displayed
--RAA14128.773615765/EXCHANGE.COMPANY.COM
Content-type: message/rfc822
[original VPIM message goes here]
--RAA14128.773615765/EXCHANGE.COMPANY.COM--
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16. Appendix C - Example Error Voice Processing Error Codes
The following common voice processing errors and their corresponding
status codes are given as examples. The text after the error codes
is intended only for reference to describe the error code.
Implementations should provide implementation specific informative
comments after the error code rather than the text below.
Error condition RFC 1893 Error codes
----------------------------- --------------------------------
Analog delivery failed 4.4.0 Persistent connection error
because remote system is busy - other
Analog delivery failed 4.4.1 Persistent protocol error
because remote system is - no answer from host
ring-no-answer
Remote system did not answer 5.5.5 Permanent protocol error
AMIS-Analog handshake ("D" in - wrong version
response to "C" at connect
time)
Mailbox does not exist 5.1.1 Permanent mailbox error
- does not exist
Mailbox full or over quota 4.2.2 Persistent mailbox error
- full
Disk full 4.3.1 Persistent system error
- full
Command out of sequence 5.5.1 Permanent protocol error
- invalid command
Frame Error 5.5.2 Permanent protocol error
- syntax error
Mailbox does not support FAX 5.6.1 Permanent media error
- not supported
Mailbox does not support TEXT 5.6.1 Permanent media error
- not supported
Sender is not authorized 5.7.1 Permanent security error
- sender not authorized
Message marked private, but 5.3.3 Permanent system error
system is not private capable - not feature capable
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17. Appendix D - Example Voice Processing Disposition Types
The following common voice processing disposition conditions and
their corresponding MDN Disposition (which contains the disposition
mode, type and modifier, if applicable) are given as examples.
Implementers should refer to [MDN] for a full description of the
format of message disposition notifications.
Notification event MDN Disposition mode, type &
modifier
------------------------------ ------------------------------------
Message played by recipient, manual-action/MDN-sent-automatically;
receipt automatically returned displayed
Message deleted from mailbox manual-action/MDN-sent-automatically;
by user without listening deleted
Message cleared when mailbox manual-action/MDN-sent-automatically;
deleted by admin deleted/mailbox-terminated
Message automatically deleted automatic-action/
when older than administrator MDN-sent-automatically; deleted/
set threshold expired
Message processed, however manual-action/MDN-sent-automatically;
audio encoding unknown - processed/error
unable to play to user Error: unknown audio encoding
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18. Appendix E - IANA Registrations
There are no changes to the registrations of the voice content
disposition parameter defined in the earlier VPIM V2 document, RFC
2421. It is presented here for information.
18.1 Voice Content-Disposition Parameter Definition
To: IANA@IANA.ORG
Subject: Registration of new Content-Disposition parameter
Content-Disposition parameter name: voice
Allowable values for this parameter:
Voice-Message - the primary voice message,
Voice-Message-Notification - a spoken delivery notification
or spoken disposition notification,
Originator-Spoken-Name - the spoken name of the originator,
Recipient-Spoken-Name - the spoken name of the recipient if
available to the originator and present if there is ONLY one
recipient,
Spoken-Subject- the spoken subject of the message, typically
spoken by the originator
Description:
In order to distinguish between the various types of audio contents
in a VPIM voice message a new disposition parameter "voice" is
defined with the preceding values to be used as appropriate. Note
that there SHOULD only be one instance of each of these types of
audio contents per message level. Additional instances of a given
type (i.e., parameter value) may occur within an attached forwarded
voice message.
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19. Appendix F - Change History: RFC 2421 (VPIM V2) to this Document
The updated profile in this document is based on the implementation
and operational deployment experience of several vendors. The
changes are categorized as general, content, transport and
compliance. They are summarized below:
1. General
- Various and substantial editorial updates to improve readability.
- Separated send rules from reception rules to aid clarity.
Clarified the behavior upon reception of unrecognized content types
(eg. Unsupported non-audio contents should be discarded to deliver
the audio message.) expected with the interworking between voice
and unified messaging systems.
- added _ Normal_ sensitivity for consistency
- should not use MDN Content-Disposition options
- reorganized the content type descriptions for clarity
2. Content
- Changed handling of received lines by a gateway to SHOULD
NOT delete in a gateway. In gateways to systems such as AMIS,
it is not possible to preserve this information. It is intended
that such systems be able to claim conformance.
- Eliminated the vCard as a supported VPIM V2 content type.
3. Transport
- None
4. Compliance
- Aligned the table of Appendix A to the requirements in the text.
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