Network Working Group Glenn Parsons
Internet Draft Nortel Technology
Expires: 12/5/1996 Greg Vaudreuil
Octel Network Services
June 12, 1996
Voice Profile for Internet Mail
<draft-ema-vpim-00.txt>
Status of this Memo
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
working documents as Internet Drafts.
Internet Drafts are valid for a maximum of six months and may be
updated, replaced, or obsoleted by other documents at any time. It is
inappropriate to use Internet Drafts as reference material or to cite
them other than as a "work in progress".
This document profiles Internet mail for voice messaging. It
obsoletes RFC 1911 which describes version 1 of the profile. A list
of changes from that document are noted in Appedix C. As well,
Appendix D lists the open issues with this version of VPIM; these
issues are noted by ** in the text.
Please send comments on this document to the EMA VPIM Work Group
mailing list: <vpim-l@ema.org>
1. Abstract
A class of special-purpose computers has evolved to provide voice
messaging services. These machines generally interface to a telephone
switch and provide call answering and voice messaging services.
Traditionally, messages sent to a non-local machine are transported
using analog networking protocols based on DTMF signaling and analog
voice playback. As the demand for networking increases, there is a
need for a standard high-quality digital protocol to connect these
machines. The following document is a profile of the Internet
standard MIME and ESMTP protocols for use as a digital voice messaging
networking protocol.
This profile is based on an earlier effort in the Audio Message
Interchange Specification (AMIS) group to define a voice messaging
protocol based on X.400 technology. This protocol is intended to
satisfy the user requirements statement from that earlier work with
the industry standard ESMTP/MIME mail protocol infrastructures already
used within corporate intrarnets. This Internet Draft will be refered
to as VPIM in this document.
Internet Draft MIME Voice Profile June 12, 1996
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,
highlighting voice and facsimile.
This document specifies a restricted profile of the Internet
multimedia messaging protocols for use between voice processing
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
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 no relaying
of message and RFC 822 header fields may have limited use in the
context of the limited messaging features currently deployed.
3) VM 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 "CC" 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 is 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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2.2 Design Goals
It is a goal of this effort to make as few restrictions and additions
to the existing Internet mail protocols as possible while satisfying
the requirements for interoperability with current 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
which do not understand MIME, though typical use is expected to be
within corporate intranets. As well, nothing in this document
precludes use of a 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.
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 recommended
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 this directory listing capabilities
is a local matter.
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3. Protocol Restrictions
This protocol does not limit the number of recipients per message.
Where possible, 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. However, ESMTP currently does
not provide a mechanism for indicating the number of supported
recipients.
This protocol does not limit the maximum message length. Implementors
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 command is in bytes, not
minutes. The number of bytes varies by voice encoding format and must
include the MIME wrapper overhead. If the length must be known before
sending, an approximate translation into minutes can be performed if
the voice encoding is known.
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4. Voice Message Interchange Format
The voice message interchange format is a profile of the Internet Mail
Protocol Suite. As such, this document assumes an understanding of
these 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 notification
[DRPT][NOTIFY][STATUS], the message disposition notifications [MDN],
and the electronic business card [DIRECTORY][VCARD].
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.
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. Administration of this space is expected to
conform to international, national or corporate private telephone
numbering plans. 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.
For example, a compliant message may contain the address
2145551212@mycompany.com. It should be noted that while the example
mailbox address is based on the North American Numbering Plan, any
other corporate numbering plan can be used. 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
Section 6).
Special addresses are provided for compatibility with the conventions
of the Internet mail system and to facilitate testing. 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.
Loopback@domain
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A special mailbox name named "loopback" SHOULD be designated for
loopback testing. If supported, all messages (including content) sent
to this mailbox MUST be returned back to the address listed in the
From: address as a new message. The originating address of the
returned address MUST be "postmaster" to prevent mail loops.
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, headers do not indicate delivery options for the transport
of messages.
The following header lines are permitted for use with VPIM voice
messages:
From
The originator's fully-qualified domain address (a mailbox address
followed by the fully-qualified domain name). The user listed in this
field should be presented in the voice message envelope as the
originator of the message.
Systems compliant to this profile SHOULD provide the text personal
name of the sender in a quoted phrase if the name is available. To
facilitate storage of the text name in a local dial-by-name cache
directory, the first and last name names must be separable. Text
names of persons in voice messages MUST be represented in the form
"last, first, mi." Text names of corporate or positional mailboxes
MAY be provided as a simple string. From [822]
Example:
From: "User, Joe S." <2145551212@mycompany.com>
From: "Technical Support" <611@mycompany.com>
To
The TO header contains the recipient's fully-qualified domain address.
There may be one or more To: fields in any message.
Example:
To: 2145551213@mycompany.com
cc
The cc header contains additional recipients' fully-qualified domain
addresses. Many voice mail systems are not capable of storing or
reporting the full list of recipients to the receiver.
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Example:
cc: 2145551213@mycompany.com
Systems compliant to this profile MAY discard the cc addresses of
incoming messages as necessary. Systems compliant to this profile
SHOULD provide a complete list of recipients when possible.
Date
The Date header contains the date, time, and time zone in which the
message was sent by the originator. Compliant implementations SHOULD
be able to convert RFC 822 date and time stamps into local time.
Example:
Date: Wed, 28 Jul 96 10:08:49 PST
The sending system MUST report the time the message was sent. From
[822]
Sender
The Sender header contains the actual address of the originator if the
message is sent by an agent on behalf of the author indicated in the
From: field. Support for this field cannot be guaranteed in voice
messaging systems and SHOULD NOT be generated by a compliant
implementation.
While it may not be possible to save this information in some voice
mail machines, discarding this information or the ESMTP MAIL FROM
address will make it difficult to send an error message to the proper
destination. From [822]
Message-id
The Message-id header contains a unique per-message identifier. A
unique message-id MUST be generated for each message sent from a
compliant implementation.
The message-id is not required to be stored on the receiving system.
This identifier MAY be used for tracking, auditing, and returning
read-receipt reports. From [822]
Example:
Message-id: <12345678@mycompany.com>
Received
The Received header contains trace information added to the beginning
of a RFC 822 message by message transport agents (MTA). This is the
only header permitted to be added by an MTA. Information in this
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header is useful for debugging when using an US-ASCII message reader
or a header parsing tool.
A compliant system MUST add Received headers when acting as a gateway
and MUST NOT remove any. These headers MAY be ignored or deleted when
the message is received at the final destination. From [822]
MIME Version
The MIME-Version header indicates that the message conforms to the
MIME message format specification. Systems compliant to the VPIM MUST
include a comment with the words "(Voice 2.0)". RFC 1911 defines an
earlier version of this profile and uses the token (Voice 1.0). From
[MIME]
Example:
MIME-Version: 1.0 (Voice 2.0)
Content-Type
The content-type header declares the type of content enclosed in the
message. One of the allowable contents is multipart, a mechanism for
bundling several message components into a single message. The
allowable contents are specified in the next section of this document.
From [MIME]
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".
The allowable content-transfer-encodings are specified in the next
section of this document. From [MIME]
Sensitivity
The sensitivity header, if present, indicates the requested privacy
level. The case-insensitive values "Personal" and "Private" are
specified. If no privacy is requested, this field is omitted.
If a sensitivity header 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 user to reply to
a sensitive message, but MUST NOT include the original message
content. The sensitivity of the reply message is set by the user.
If the receiving system does not support privacy and the sensitivity
is one of "Personal" or "Private", the message MUST be returned to the
sender with an appropriate error code indicating that privacy could
not be assured and that the message was not delivered. From: [X400]
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Importance
Indicates the requested priority 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 assumed to be "normal".
Compliant implementations MAY use this header to indicate the
importance of a message and may order messages in a recipient's
mailbox. From: [X400]
Subject
The subject field is often provided by email systems but is not widely
supported on Voice Mail platforms. For compatibility with text based
mailbox interfaces, a text subject field SHOULD be generated by a
compliant implementation but MAY be discarded if present by a
receiving system. From [822]
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 Voice Message'.
4.3 Message Content Types
MIME is a general-purpose message body format that is extensible to
carry a wide range of body parts. The basic protocol is described in
[MIME]. MIME also provides for encoding binary data so that it can be
transported over the 7-bit text-oriented SMTP protocol. This
transport encoding is independent of the audio encoding designed 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, both will
work. Where binary transport is available, no transport encoding is
needed, and the data can be labeled as "Binary".
An implementation in conformance with this profile SHOULD send audio
data in binary form when binary message transport is available. When
binary transport is not available, implementations MUST encode the
message 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.
The following content types are identified for use with this profile.
Note that each of these contents can be sent individually in a message
or wrapped in a multipart/mixed to form a more complex structure..
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Message/RFC822
MIME requires support of the Message/RFC822 message encapsulation body
part. This body part is used to forward complete messages within a
multipart/mixed message. From [MIME]
Text/Plain
MIME requires support of the basic Text/Plain content type. This
content type has no applicability within the voice messaging
environment. Compliant implementations MUST NOT send the Text/Plain
content-type. Compliant implementations MUST accept Text/Plain
messages, however, specific handling is left as an implementation
decision. From [MIME]
There are several mechanisms that can be used to support text on voice
messaging systems including text-to-speech and text-to-fax
conversions. If no viewing of the text is possible, the entire
message MUST be non-delivered and returned to the sender with a media-
unsupported error code.
Multipart/Mixed
MIME provides the facilities for enclosing several body parts in a
single message. Multipart/Mixed SHOULD be used for sending multi-
segment voice messages, that is, to preserve across the network the
distinction between an annotation and a forwarded message, or between
a spoken subject and the voice message. Compliant systems MUST accept
multipart/mixed body parts. Systems MAY collapse such a multi-segment
voice or fax message into a single segment if multi-segment messages
are not supported on the receiving machine. From [MIME]
**Application/Directory
The spoken name and the spelled name of the message sender SHOULD be
sent with each message in an Application/Directory content type
[DIRECTORY]. If included in a message, the Versit VCARD profile MUST
be used [VCARD] and MUST specify at least the "N", "SOUND", and
"EMAIL" types and MAY use the other types defined in [VCARD]
The spoken name SHOULD be included inline in the "SOUND" type using a
Base64 encoding of 32KADPCM. As well, the _EMAIL_ type MAY also
include a `VPIM' token to avoid confusion with a user's text email
address (if they are different).
Example:
BEGIN: vCard
N: Parsons;Glenn
ORG: Nortel Technology
TEL;TYPE=VOICE,MSG,WORK: +1-613-763-7582
EMAIL;TYPE=INTERNET: glenn.parsons@nortel.ca
EMAIL;TYPE= INTERNET,VPIM: 6137637582@nortel.ca
SOUND;TYPE=32KADPCM;ENCODE=BASE64;VALUE=INLINE:
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iIiIiIjMzN3czdze3s7d7fwfHhcvESJVe/4yEhLz8/FOQjVFRERCESL/zqrq
(This is the Spoken Name audio data) 3Or/zrPCzxv43u3L7buR3b0
AAEAAAAIAAAAFQEDAAEAAAABAAAAFgEEAAEAAACqCAAAFwEEAAEAAAD1uQEA
GgEFAAEAAAAIugEAGwEFAAEAAAAQugEAJAEEAAEAAAAEAAAAAAAAAA==
END: vCard
Multipart/Report
The Multipart/Report is used for enclosing a Message/Notification and
Message/Disposition-notification body parts and any returned message
content. Compliant implementations MUST use the Multipart/Report
construct when returning messages, sending warnings, or issuing read
receipts. Compliant implementations MUST recognize and decode the
Multipart/Report content type. From [REPORT]
**Message/Notification
This MIME body part is used for sending machine-parsable delivery
status notifications. Compliant implementations must use the
Message/Notification construct when returning messages or sending
warnings. Compliant implementations must recognize and decode the
Message/Notification content type and present the reason for failure
to the user. From [NOTIFY]
**Message/Disposition-notification
This MIME body part is used for sending machine-parsable read-receipt
and extended-absence status notifications. Compliant implementations
must use the Message/Disposition-notification construct when sending
post-delivery message status notifications. Compliant implementations
must recognize and decode the Message/Disposition-notification content
type and present the reason for failure to the user. From [MDN]
Audio/32KADPCM
CCITT Recommendation G.721 [G721] describes the algorithm recommended
for conversion of a 64 KB/s A-law or u-law PCM channel to and from a
32 KB/s channel. The conversion is applied to the PCM stream using an
Adaptive Differential Pulse Code Modulation (ADPCM) transcoding
technique. From [1911].
An implementation compliant to this profile MUST use Audio/32KADPCM by
default for voice.
While any valid MIME body header MAY be used, several headers have the
following semantics when included with this body part:
Content-Description:
This field SHOULD be present to allow the text identification of
these body parts. If more than one Audio/32KADPCM body occurs
within a single multipart/mixed, then this header MUST be present
to allow differentiation. It is recommended that the following
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values be used as appropriate: VPIM Voice Message, VPIM Spoken
Name, VPIM Spoken Subject.
Content-Duration:
This field MAY be present to allow the specification of the length
of the bodypart in seconds. The use of this field on reception is
a local implementation issue.
Content-Language:
This field MAY be present to allow the specification of the spoken
language of the bodypart. The encoding is defined in [LANG] (e.g.
EN-UK for UK English). The use of this field on reception is a
local implementation issue.
Proprietary Voice Formats
Proprietary voice encoding formats or other standard formats may be
supported under this profile provided a unique identifier is
registered with the IANA prior to use. These voice encodings should
be registered as sub-types of Audio.
Use of any other encoding except Audio/32KADPCM reduces
interoperability in the absence of explicit manual system
configuration. A compliant implementation MAY use any other encoding
with explicit per-destination configuration.
NOTE: The following fax bodies are examples, the choice of which
to include in VPIM v2 is an open issue.
**Image/TIFF
TMA-AMIS-D is using the following definition:
The ASN.1 definition from X.400 for fax is:
G3Fax ::= SEQUENCE {
SET{numberOfPages
[0] IMPLICIT INTEGER OPTIONAL,
[1] IMPLICIT P1.G3NonBasicParams OPTIONAL},
SEQUENCE OF BIT STRING}
We have defined sequence of bit string as:
BIT STRING shall contain a TIFF G3/T.4 image (one page), including the
TIFF header. A fax is a sequence of BIT STRING, one for each page. The
compression type is (tag 259) is 3 (for T.4 encoded); and the TIFF tag
292 is 0 to indicate a basic 1-D modified Huffman (MH) encoding, 1 for
2-D MR encoding (k-8).
The P1.G3NonBasicParams shall be absent. #numberOfPages# is optional,
but should be included if available. The absense of
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P1.G3NonBasicParams together with a normal TIFF header will indicate
the bodypart is in TIFF format instead of G3.
ECTF S.100 is using the following definition:
All implementations must be able to read (send) TIFF files meeting the
requirements below. Image data must not have any coding errors.
Implementations may also read any other formats as long as available
formats can be disclosed to applications at run time.
ByteOrder: MM,II (Either byte order is allowed)
These tags shown below must be readable. If not present, reader must
use default shown:
TIFF Reader Tags
TAG Legal Values Default Comment
BitsPerSample 1 1 one bit per
sample
CleanFaxData 0 0 data has no
errors
Compression 3 3 T.4 bi-level
encoding, MH
FillOrder 2,1 2 LSB first or
MSB first
ImageWidth 1728 1728
ImageLength > 0 required
NewSubFileType 2 2 single page
of multipage
file
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Orientation 1 1 1st row=top
left, 1st
col=top
PageNumber X/X 0/1 pg/tot, 0
base, tot in
1st IFD
PhotometricInterp 0 0 0 is white
ResolutionUnit 2 2 inches
RowsPerStrip =ImageLength =ImageLength
SamplesPerPixel 1 1 one sample
per pixel
StripByteCounts >0 required
StripOffsets >0 required
T4Options 4 4 MH, byte
aligned EOL
Xresolution 204,200 204
Yresolution 196,98,100, 196
200
For fax writing (receiving), implementations are required to use the
following TIFF format as a default. Image data must not have any
coding errors. Implementations may write other formats as long as
applications have selected from among those formats at run time.
TIFF Writer Tags
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TAG Legal Values Comment
ByteOrder: II
BitsPerSample 1 one bit per sample
Compression 3 T.4 bi-level encoding, MH
FillOrder 2 LSB first
ImageWidth 1728
ImageLength > 0
NewSubFileType 2 single page of multi-page file
PageNumber X/X pg/tot, 0 base, tot in 1st IFD
PhotometricInterp 0 0 is white
ResolutionUnit 2 inches
RowsPerStrip >0 must be same as ImageLength
SamplesPerPixel 1 one sample per pixel
StripByteCounts >0 as appropriate
StripOffsets >0 as appropriate
T4Options 4 MH, byte aligned EOL
Xresolution 204, 200
Yresolution 196,98, 100,
200
Tags that are optional, but if present must contain the values as
shown:
Optional TIFF Writer Tags
TAG Legal Comment
Values
CleanFaxData 0 data doesn't contain bad scan
lines
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Orientation 1 1st row = top left, 1st col = top
Recommended informational tags are:
Software, Datetime, BadFaxLines, ConsecutiveBadFaxLines
The VPIM demo used the following definition:
All implementations must generate and read facsimile bodies with the
TIFF tags listed below. Only one page is permitted per TIFF body
part.
Note: insert Nagendra's table here
**image/g3fax
This content-type is defined, as part of the MIXER series, to carry G3
Facsimile byte streams. It specifies a MIME equivalent to the X.400
G3 facsimile body part. It is defined in [MIXERFAX] and must be used
as specified.
4.4 CompliantCompliantForwarded Messages
VPIM version 2 explicitly supports the forwarding of voice and fax
content with voice or fax annotation. Forwarded VPIM messages SHOULD
be sent as a multipart/mixed with the entire original message enclosed
in a message/rfc822 content type and the annotation as a separate
Audio/* body part.
In the event that the RFC822 headers are not available for the
forwarded content, simulated headers with information as available
SHOULD be constructed to indicate the original sending timestamp, and
the original sender as indicated in the "From" line. The
message/rfc822 content MUST include at least the MIME-Version: 1.0
(Voice 2.0), the MIME content type and MIME content-encoding header as
necessary.
In the event that forwarding information is lost through
concatentation of the original message and the forwarding annotation,
such as must be done in an AMIS to VPIM gateway, the entire content
MAY be sent as a single Audio/* segment without including any
forwarding semantics.
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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 networking 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.
5.1 ESMTP Commands
HELO
Base SMTP greeting and identification of sender. This command is not
to be sent by compliant systems unless the more-capable EHLO command
is not accepted. It is included for compatibility with general SMTP
implementations. Compliant implementations MUST implement the HELO
command for backward compatibility but SHOULD NOT send it unless EHLO
is not supported. From [SMTP]
MAIL FROM (REQUIRED)
Originating mailbox. This address contains the mailbox to which
errors should be sent. This address may not be 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.
Compliant implementations MUST implement the extended MAIL FROM
command. From [SMTP, ESMTP]
RCPT TO
Recipient's mailbox. This field contains only the addresses to which
the message should be delivered for this transaction. In the event
that multiple transport connections to multiple destination machines
are required for the same message, this list may not match the list of
recipients in the message header. Compliant implementations MUST
implement the extended RCPT TO command. From [SMTP, ESMTP]
DATA
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Initiates the transfer of message data. Support for this command is
required in the event the binary mode command BDAT is not supported by
the remote system. Compliant implementations MUST implement the SMTP
DATA command for backwards compatibility. From [SMTP]
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]
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]
RSET
Resets the connection to its initial state. Compliant implementations
MUST implement the RSET command. From [SMTP]
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]
EHLO
The enhanced mail greeting that enables a server to announce support
for extended messaging options. The extended messaging modes are
discussed in a later section of this document. Compliant
implementations MUST implement the ESMTP command and return the
capabilities indicated later in this memo. From [ESMTP]
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]
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5.2 ESMTP Keywords
The following ESMTP keywords indicate extended features useful for
voice messaging.
PIPELINING
The "PIPELINING" keyword indicates ability of the receiving server to
accept pipelined commands. 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 parameter. From [PIPE]
SIZE
The "SIZE" keyword provides a mechanism by which the receiving SMTP
can indicate the maximum size message supported. Compliant
implementations MUST provide the size capability and SHOULD honor any
size limitations when sending. From [SIZE]
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 SHOULD support binary
transport indicated by this capability. From [BINARY]
BINARYMIME
The "BINARYMIME" keyword indicates that the receiver SMTP can accept
binary encoded MIME messages. Compliant implementations SHOULD support
binary transport indicated by this capability. From [BINARY]
NOTIFY
The "NOTIFY" keyword indicates that the receiver SMTP will accept
explicit delivery status notification requests. Compliant
implementations MUST support the delivery notification extensions in
[DSN].
5.3 ESMTP Parameters - MAIL FROM
BINARYMIME
The current message is a binary encoded MIME messages. Compliant
implementations SHOULD support binary transport indicated by this
parameter. From [BINARY]
5.4 ESMTP Parameters - RCPT TO
NOTIFY
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The NOTIFY parameter indicates the conditions under which a delivery
report should be sent. Compliant implementations MUST honor this
request. From [DSN]
RET
The RET parameter indicates whether the content of the message should
be returned. Compliant systems SHOULD honor a request for returned
content. From [DSN]
6. ** Directory Address Resolution
It is the responsibility of a VPIM system to lookup the fully-
qualified domain name (FQDN) based on the address entered by the user.
The mapping of this dialed number to a final destination system can be
accomplished through implementation-specific means. However, the
Internet protocols provide several possible scalable mechanisms for
the resolution of a routable address from a given public telephone
number. VPIM specifies the use of LDAP...
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 SHOULD be
managed. MIB II SHOULD be implemented to provide basic statistics and
reporting of TCP and IP protocol performance. [MIB II]
7.2 Directory and Message Management
Compliant systems SHOULD provide for the management of message traffic
and queue monitoring based on the Message and Directory MIB. [MADMAN]
8. Conformance Requirements
In order to be called VPIM compliant, a voice messaging system must
implement all mandatory features of this profile in each of four
areas: Content, Transport, Notifications and Directory. In addition,
systems which conform to this profile must not send messages with
features beyond this profile unless explicit per-destination
configuration of these enhanced features is provided. Such
configuration information could be stored in a directory, though the
implementation of this is a local matter.
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It is also possible, though not encouraged, to claim conformance to
only specific areas (e.g. VPIM content compliant) of this profile.
The delineation of these areas is as follows:
Content - Section 4, except VCARD, REPORT, NOTIFY & MDN
Transport - Section 5 except NOTIFY & RET, and Section 7
Notifications - REPORT, NOTIFY & MDN from Section 4 and NOTIFY
& RET from Section 5
Directory - VCARD from Section 4 & Section 6
A summary of compliance requirements is contained in Appendix A.
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9. References
[MIME] Borenstein, N., and N. Freed, "Multipurpose Internet Mail
Extensions", RFC 1521, Bellcore, Innosoft, Sept 1993.
[MSG822] Crocker, D., "Standard for the Format of ARPA Internet Text
Messages", STD 11, RFC 822, UDEL, August 1982.
[X400] Hardcastle-Kille, S., "Mapping between X.400(1988) / ISO 10021
and RFC 822", RFC 1327, May 1992.
[PIPE] Freed, N., Cargille, A., "SMTP Service Extension for Command
Pipelining" RFC 1854, October 1995.
[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.
[SIZE] Klensin, J, Freed, N., Moore, K, "SMTP Service Extensions for
Message Size Declaration" RFC 1870, United Nations University,
Innosoft International, Inc., November 1995.
[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.
[DNS1] Mockapetris, P., "Domain names - implementation and
specification", RFC1035, Nov 1987.
[DNS2] Mockapetris, P., "Domain names - concepts and facilities", RFC
1034, Nov 1987.
[SMTP] Postel, J., "Simple Mail Transfer Protocol", STD 10, RFC 821,
USC/Information Sciences Institute, August 1982.
[BINARY] Vaudreuil, G., "SMTP Service Extensions for Transmission of
Large and Binary MIME Messages", RFC 1830, October 1995.
[NOTIFY] Vaudreuil, G., Moore, K., "An Extensible Message Format for
Delivery Status Notifications", Internet Draft <draft-ietf-notary-
mime-delivery-02-txt>
[REPORT] Vaudreuil, G., "Multipart/Report", Internet-Draft, <draft-ietf-
notary-mime-report-04.txt>
[DSN] Moore, K. "SMTP Service Extensions for Delivery Status
Notifications", Internet Draft <draft-ietf-notary-smtp-drpt-03.txt>.
[G721] CCITT Recommendation G.700-G.795 (1988), General Aspects of
Digital Transmission Systems, Terminal Equipment. Blue Book.
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[MADMAN] N. Freed, S. Kille, "Mail Monitoring MIB", RFC 1566, Jan 1994.
[MIB II] M. Rose, "Management Information Base for Network Management of
TCP/IP-based internets: MIB-II", RFC 1158, May 1990.
[RELATED] Levinson, E., _The MIME Multipart/Related Content-type_, RFC
1872, Dec 1995
[MDN] Fajman, Roger, _An Extensible Message Format for Message
Disposition Notifications_ <draft-ietf-receipt-MDN-00.txt>
[DIRECTORY] Howes, Tim, Smith, Mark, _A MIME Content-Type for Directory
Information_ <draft-ietf-asid-mime-direct-01.txt>
[VCARD] Dawson, Frank, Howes, Tim, "An Application/Directory MIME
Content-Type Electronic Business Card Profile" <draft-ietf-asid-mime-
vcard-00.txt>
[LANG] H. Alvestrand, "Tags for the Identification of Languages", RFC
1766, 03/02/1995
10. Security Consideration
This document is a profile of existing Internet mail protocols. As
such, it does not create any security issues not already existing in
the profiled Internet mail protocols themselves.
Further, the profile specified in this document does not in any way
preclude the use of any Internet mail security protocol to encrypt,
authenticate, or non-repudiate the messages.
11. Acknowledgments
The authors would like to offer a special thanks to the Electronic
Messaging Association, especially the members of the Voice Messaging
Committee, for their support of the VPIM specification and.the efforts
they have made to ensure its success.
12. Authors' Addresses
Glenn W. Parsons
Nortel Technology
P.O. Box 3511, Station C
Ottawa, ON K1Y 4H7
Canada
Phone: +1-613-763-7582
Fax: +1-613-763-8385
Glenn.Parsons@Nortel.ca
Gregory M. Vaudreuil
Octel Network Services
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17080 Dallas Parkway
Dallas, TX 75248-1905
United States
Phone/Fax: +1-214-733-2722
Greg.Vaudreuil@Octel.Com
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13. Appendix A - VPIM Requirements Summary
| | | | |S| |
| | | | |H| |F
| | | | |O|M|o
| | |S| |U|U|o
| | |H| |L|S|t
| |M|O| |D|T|n
| |U|U|M| | |o
| |S|L|A|N|N|t
| |T|D|Y|O|O|t
FEATURE |SECTION | | | |T|T|e
-------------------------------------------|----------|-|-|-|-|-|-
| | | | | | |
Message Addressing Formats: | | | | | | |
Use DNS host names |4.1 |x| | | | |
Use only numbers in mailbox IDs |4.1 | |x| | | |
Use alpha-numeric mailbox IDs |4.1 | | |x| | |
Support of postmaster@domain |4.1 |x| | | | |
Support of loopback@domain |4.1 | |x| | | |
| | | | | | |
Message Header Fields: | | | | | | |
Encoding outbound messages | | | | | | |
From |4.2 |x| | | | |
Addition of text name |4.2 | |x| | | |
To |4.2 |x| | | | |
cc |4.2 | |x| | | |
Date |4.2 |x| | | | |
Sender |4.2 | | | |x| |
Message-id |4.2 |x| | | | |
Received |4.2 |x| | | | |
MIME Version: 1.0 (Voice 2.0) |4.2 |x| | | | |
Content-Type |4.2 |x| | | | |
Content-Transfer-Encoding |4.2 |x| | | | |
Sensitivity |4.2 | | |x| | |
Importance |4.2 | | |x| | |
Subject |4.2 | |x| | | |
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Detection & Decoding inbound messages | | | | | | |
From |4.2 |x| | | | |
Utilize text personal name |4.2 | |x| | | |
To |4.2 |x| | | | |
cc |4.2 | | |x| | |
Date |4.2 |x| | | | |
Conversion of Date to local time |4.2 | |x| | | |
Sender |4.2 | | | |x| |
Message ID |4.2 |x| | | | |
Received |4.2 | | |x| | |
MIME Version: 1.0 (Voice 2.0) |4.2 |x| | | | |
Content Type |4.2 |x| | | | |
Content-Transfer-Encoding |4.2 |x| | | | |
Sensitivity |4.2 |x| | | | |1
Importance |4.2 | | |x| | |
Subject |4.2 | | |x| | |
| | | | | | |
Message Content Encoding: | | | | | | |
Encoding outbound messages | | | | | | |
7BITMIME |4.3 | | | | |x|
8BITMIME |4.3 | | | | |x|
Quoted Printable |4.3 | | | | |x|
Base64 |4.3 |x| | | | |2
Binary |4.3 | |x| | | |3
Detection & decoding inbound messages | | | | | | |
7BITMIME |4.3 |x| | | | |
8BITMIME |4.3 |x| | | | |
Quoted Printable |4.3 |x| | | | |
Base64 |4.3 |x| | | | |
Binary |4.3 |x| | | | |3
| | | | | | |
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Message Content Types: | | | | | | |
Inclusion in outbound messages | | | | | | |
Message/RFC822 |4.3 | | |x| | |
Text/plain |4.3 | | | | |x|
Multipart/Mixed |4.3 | |x| | | |
Application/Directory |4.3 | |x| | | |
Multipart/Report |4.3 |x| | | | |
Message/Notification |4.3 |x| | | | |
Message/Disposition-notification |4.3 |x| | | | |
Audio/32KADPCM |4.3 |x| | | | |
Content-Description |4.3 | | |x| | |
Content-Duration |4.3 | | |x| | |
Content-Langauge |4.3 | | |x| | |
Audio/* (proprietary encodings) |4.3 | | |x| | |
** Image/TIFF |4.3 |x| | | | |
** Image/g3fax |4.3 |x| | | | |
Detection & decoding in inbound messages | | | | | | |
Message/RFC822 |4.3 |x| | | | |
Text/plain |4.3 |x| | | | |4
Multipart/Mixed |4.3 |x| | | | |
Application/Directory |4.3 | |x| | | |
Multipart/Report |4.3 |x| | | | |
Message/Notification |4.3 |x| | | | |
Message/Disposition-notification |4.3 |x| | | | |
Audio/32KADPCM |4.3 |x| | | | |
Content-Description |4.3 | | |x| | |
Content-Duration |4.3 | | |x| | |
Content-Langauge |4.3 | | |x| | |
Audio/* (proprietary encodings) |4.3 | | |x| | |
** Image/TIFF |4.3 |x| | | | |
** Image/g3fax |4.3 |x| | | | |
| | | | | | |
Message Transport Protocol: | | | | | | |
ESMTP Commands | | | | | | |
HELO |5.1 |x| | | | |
MAIL FROM |5.1 |x| | | | |
RCPT TO |5.1 |x| | | | |
DATA |5.1 |x| | | | |
TURN |5.1 | | | | |x|
QUIT |5.1 |x| | | | |
RSET |5.1 |x| | | | |
VRFY |5.1 | | |x| | |
EHLO |5.1 |x| | | | |
BDAT |5.1 | |x| | | |3
ESMTP Keywords & Parameters | | | | | | |
PIPELINING |5.2 | |x| | | |
SIZE |5.2 |x| | | | |
CHUNKING |5.2 | |x| | | |
BINARYMIME |5.3 | |x| | | |
NOTIFY |5.2,5.4 |x| | | | |
RET |5.4 | |x| | | |
| | | | | | |
**Directory Protocols: | | | | | | |
LDAP |6.0 | | | | | |
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| | | | | | |
Management Protocols: | | | | | | |
Network management |7.1 | |x| | | |
Monitoring queues |7.2 | |x| | | |
-------------------------------------------|----------|-|-|-|-|-|-
1. 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.
2. When binary transport is not available
3. When binary transport is available
4. If the text cannot be presented in some form, the entire message
MUST be non-delivered.
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14. Appendix B - Example Voice Messages
The following message is a full-featured, all-options-enabled message
addressed to two recipients. The message includes the sender's spoken
name and a short speech segment. The message is marked as important
and private.
To: 2145551212@vm1.mycompany.com
To: 2145551234@VM1.mycompany.com
From: "Vaudreuil, Greg" <2175552345@VM2.mycompany.com>
Date: Mon, 26 Aug 93 10:20:20 CST
MIME-Version: 1.0 (Voice 2.0)
Content-type: Multipart/Mixed; Boundary="MessageBoundary"
Content-Transfer-Encoding: 7bit
Message-ID: VM2.mycompany.com-123456789
Sensitivity: Private
Importance: High
--MessageBoundary
Content-type: Audio/32KADPCM
Content-Transfer-Encoding: Base64
iIiIiIjMzN3czdze3s7d7fwfHhcvESJVe/4yEhLz8/FOQjVFRERCESL/zqrq
q83cLOr/zrPCzxv43u3L7buR3b0/G8HussEbutwtITFSE+dUEl3+79vv/Ruy
(This is a sample of the base64 message data) zb8tFdLTQt1PXj
QyKpbnNTyfFCvvje0e0UQd4RL6r6Gcybs7TjHOJh3xU/ND899dzNdRbCLG3t
u7wjOyRhws+krdns7Rju0t4tLF7cE0K0MxOTOnRW/Pn30c8uHi9==
--MessageBoundary
Content-type: Application/Directory
Content-Transfer-Encoding: 7bit
BEGIN: Vcard
N: Vaudreuil;Greg;;Mr.;
SOUND;TYPE=32kbADPCM;ENCODE=BASE64;VALUE=INLINE:
iIiIiIjMzN3czdze3s7d7fwfHhcvESJVe/4yEhLz8/FOQjVFRERCESL/zqrq
(This is the Spoken Name audio data) 3Or/zrPCzxv43u3L7buR3b0
AAEAAAAIAAAAFQEDAAEAAAABAAAAFgEEAAEAAACqCAAAFwEEAAEAAAD1uQEA
GgEFAAEAAAAIugEAGwEFAAEAAAAQugEAJAEEAAEAAAAEAAAAAAAAAA==
REV: 19951031T222710Z
END: Vcard
--MessageBoundary--
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The following message is a forwarded single segment voice.
To: 2145551212@vm1.mycompany.com
From: "Vaudreuil, Greg" <2175552345@VM2.mycompany.com>
Date: Mon, 26 Aug 93 10:20:20 CST
MIME-Version: 1.0 (Voice 2.0)
Content-type: Multipart/Mixed; Boundary="MessageBoundary"
Content-Transfer-Encoding: 7bit
Message-ID: VM2.mycompany.com-123456789
--MessageBoundary
Content-type: Audio/32KADPCM
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: 2175552345@VM2.mycompany.com
From: "Parsons, Glenn, W." <2145551234@VM1.mycompany.com>
From: Date: Mon, 26 Aug 93 8:23:10 EST
MIME-Version: 1.0 (Voice 2.0)
Content-type: Audio/32KADPCM
Content-Transfer-Encoding: Base64
glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
(This is the original message audio data) fgwersdfmniwrjj
jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gQ5tkjpokfgW
dlkgpokpeowrit09==
--MessageBoundary
Content-type: Application/Directory
Content-Transfer-Encoding: 7bit
BEGIN: Vcard
N: Vaudreuil;Greg;;Mr.;
SOUND;TYPE=32kbADPCM;ENCODE=BASE64;VALUE=INLINE:
glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
(This is the Spoken Name audio data) fgwersdfmniwrjjedfsa
jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gQ5tkjpokfgW
dlkgpokpeowrit09==
REV: 19951031T222710Z
END: Vcard
--MessageBoundary_
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Appendix C - Change History: RFC 1911 to this Document
1. General
This update is based on the experience of a proof of concept
demonstration of VPIM at EMA'96. This version of the profile is
significantly different from the previous. Other general changes:
- Various editorial updates
- Changed the Voice version to 2.0
- Changed all references to Base64 from Base-64
- Corrected examples to put addresses within brackets, eliminate
spaces in the boundary="dd" construct, and other clean ups.
2. Content
- Eliminated multipart/voice-message and reworked examples to avoid
use of multipart/voice-message
- Explicitly defined the forwarding model using message/RFC822
- Eliminated the text name in the "To" and "CC" headers. Edited the
conformance to require last-name, first-name only for persons
- Profiled the application/directory body part
3. Transport
- Moved Binary support to optional
4. Compliance
- Added an explicit section on compliance
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Appendix D - Open Issues
1)
return in the event of non-support
2)
Need to verify the inline handling and the feasability of the "N"
encoding for the name. We may have to use "FN" with a VPIM defined
structure of simply last-name, first-name. (need to prototype)
3)
4)
status code for NOTIFY
5)
extended status code for MDN. (only read-receipt and extended
absence/Vacation)
6)
7)
recommendation as optional
8)
with a different content-description
9)
10)
11)
12)
13)
14)
to the different levels of conformance?
15)
16)
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