view Side-By-Side changes
Network Working Group Greg Vaudreuil
Internet Draft Octel Network Services
Expires: September 1, 1995 March 21, 11/5/1995 May 5, 1995
MIME/ESMTP Profile for
Voice Messaging
<draft-umig-mime-voice-02.txt>
<draft-umig-mime-voice-03.txt>
Changes From the previous version
1) Discussion about interoperation between this Message format profile and AMIS-
Digital was deleted. Such a gateway is outside the scope of this
document. processing rules are more clearly
separated.
2) The Text/Signature body part Much tutorial text was dropped in favor of a simpler
mechanism for Spoken-Name support. Spoken name will be contained as
an additional audio/* segment in a multipart.
Work toward Text/Signature will continue in conjunction eliminated. A basic familiarity with Internet
Directory services but the
SMTP/MIME protocols is not expected to be completed in now uniformly assumed. Text describing the near
term.
3) The document was edited
voice messaging environment remains to reflect a clearer notion of what promote understanding between
the
role of this profile is.
4) IANA Registration of Audio/32KADPCM traditional email community and Multipart/VM is now
included as an appendix.
5) The general level of requirement was reduced. Support of the
binary SMTP extensions is now listed as recommended.
6) Discussion of forwarded messages was added.
7) The status of the SMTP TURN command was changed to discouraged. It
is not clear how voice processing community.
3) Text using the TURN command should function within words "Recommended", "Required", "Optional" and
"Discouraged" has been replaced with the ESMTP
framework. more normal "Must", "Must
Not", "Should", and "Should Not".
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".
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
Internet Draft MIME Voice Profile March 21, 1995
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
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 internets. This profile will be called the
voice profile in this document.
Internet Draft MIME Voice Profile May 5, 1995
2. Scope and Design Goals
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 including
voice and facsimile.
This document specifies a profile of the TCP/IP multimedia messaging
protocols for use by special-purpose voice processing platforms.
These platforms have historically been special-purpose computers and
often do not have facilities normally associated with a traditional
Internet Email-capable computer. This profile is intended to specify
the minimum common set of features and functionaly functionally for conformant
systems.
The voice profile does not place limits on the use of additional media
types or protocol options. However, systems which are conformant to
this profile should 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.
The following are typical restrictions of voice messaging platform
which were considered in creating this baseline profile.
1)Text
1) Text messages are not normally received and often cannot be
displayed or viewed. They can often be processed only via advanced
text-to-speech or text-to-fax features not currently present in
these machines.
2)Voice
2) Voice mail (VM) machines usually act as an integrated Message
Transfer Agent and a User Agent. The VM voice mail machine is
responsible for final delivery, and there is no relaying of
messages. RFC 822 header fields may have limited use in the
context of the simple messaging features currently deployed.
3)VM
3) VM message stores are generally not capable of preserving the
full semantics of an Internet message. As such, use of a VM voice
mail machine for general
Vaudreuil Expires 9/1/95 [Page 2]
Internet Draft MIME Voice Profile March 21, 1995 message forwarding and gatewaying is not
supported. Storage of "Received" lines and "Message-ID" may be
limited.
4) Nothing in this document precludes use of a general purpose
email gateway from providing these services. However, severe
performance degradation may result if the email gateway does not
support the ESMTP options recommended by this document.
5) Internet-style mailin mailing lists are not generally supported.
Distribution lists are implemented as local alias lists.
6) There is generally no human operator. Error reports must be
machine-parsable so that helpful responses can be given to users
whose only access mechanism is a telephone.
Vaudreuil Expires 11/5/95 [Page 2]
Internet Draft MIME Voice Profile May 5, 1995
7) The system user names are often limited to 16 or fewer numeric
characters. Alpha characters are not generally used for mailbox
identification as they cannot be easily entered from a telephone
terminal.
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 user requirements for interworking 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. It is expected that a 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 expected that the system administrator will 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.
This specification is a profile of the relevant TCP/IP Internet
protocols. These technologies, as well as the specifications for the
Internet mail protocols, are defined in the Request for Comment (RFC)
document series. That series documents the standards as well as the
lore of the TCP/IP protocol suite. This document should be read with
the following RFC documents: RFC 821, Simple Mail Transfer Protocol;
RFC 822, Standard for the format of ARPA Internet Messages; RFC 1521
and RFC 1522, Multipurpose Internet Mail Extensions; RFC 1651, RFC
1652, and RFC 1653, SMTP Service Extensions (ESMTP); and RFC 1034 and
RFC 1035, Domain Name System. Where additional functionality is
needed, it will be defined in this document or in an appendix.
Vaudreuil Expires 9/1/95 11/5/95 [Page 3]
Internet Draft MIME Voice Profile March 21, May 5, 1995
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, 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
ESMTP 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.
Vaudreuil Expires 9/1/95 11/5/95 [Page 4]
Internet Draft MIME Voice Profile March 21, May 5, 1995
4. Voice Message Interexchange Format Profile
The voice profile is based on and message interchange format is consistent with a profile of the TCP/IP Internet
Email Protocol Suite with newly standardized options for enhanced
functionality and performance. This section is an overview and profile
of Suite. It requires components from the necessary protocols as applied to message format
standard for Internet messages {RFC822], the voice messaging
environment. Multipurpose Internet
Message Addressing Formats
RFC 822 and SMTP addressing Extensions [MIME], the X.400 gateway specification [X.400],
and the delivery report specifications [DRPT][STATUS].
4.1 Message Addressing Formats
The RFC 822 uses 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 or node
identification. These two components are separated by the commercial
"@" symbol.
The local part of the address is shall be an ASCII string uniquely
identifying a mailbox on a destination system. The 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 national or corporate private telephone numbering plans.
While alpha characters and long mailbox identifiers are permitted,
most voice mail networks rely on numeric mailbox identifers identifiers to retain compatability
compatibility with the limited 10 digit telephone keypad.
The domain part of the address is a hierarchical global name for all
machines. For participation in the international Internet network or
for integration within a corporate internet, each VM machine is
required to have a unique domain name. In the domain name system, a
name is registered with the Internet Assigned Number Authority (IANA).
The IANA may delegate the management of a branch of the naming space
to a company or service provider.
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 VM voice mail machine to lookup the fully-qualified
domain name (FQDN) based on the address entered by the user. The
mapping of dialed address to VM final destination system is generally
accomplished through implementation-specific means.
Mapping of the FQDN to a specific network destination is generally
performed by the Domain Name System. For networks with a small number
of machines, a locally-maintained host table database can be used as a
simpler alternative.
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. Some special addresses are as follows:
Vaudreuil Expires 9/1/95 [Page 5]
Internet Draft MIME Voice Profile March 21, 1995
Postmaster@domain
By convention, a special mailbox named "postmaster" should 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 a individual
implementation choice.
Loopback@domain
A special mailbox name named "loopback" should SHOULD be designated for
loopback testing. All If supported, all messages sent to this mailbox must
MUST be returned back to the sender address listed in the From: address as a
Vaudreuil Expires 11/5/95 [Page 5]
Internet Draft MIME Voice Profile May 5, 1995
new message. The originating address should of the returned address MUST be "postmaster".
Because VMs may use alpha-numeric addresses, these
"postmaster" to prevent mail loops.
These two addresses are RESERVED so they do not conflict with any
internal addressing plan.
Internal to VM, a specific numeric address for DTMF entry can be
mapped to "loopback".
Note that without network level authentication, the loopback address
can be used to routing messages through a third-party VM to spoof
another device or to avoid toll charges. It is recommended that the
loopback feature be disabled except when testing the networking
between machines.
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.
RFC 822 defines a set of standard message header fields. This set is
extended in several RFCs.
Note that the specific order of
The following header lines is not specified. The
order cannot be expected to be preserved when sent through
intermediate gateways. The following header fields must be supported.
From are permitted for use with voice messages.
From
The originator's fully-qualified domain address (a mailbox number 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.
It is recommended that all messages contain
Systems conformant to this profile SHOULD provide the text personal
name of the sender in a quoted phrase if available. The To facilitate
storage of the text name must in a local dial-by-name cache directory, the
first and last name MUST be separable. Text names in voice messages
MUST be represented in the form "last, first, mi." From [822]
Vaudreuil Expires 9/1/95 [Page 6]
Internet Draft MIME Voice Profile March 21, 1995
Example:
From: "User, Joe S." <2145551212@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.
It is recommended that all addressees contain
Systems conformant to this profile SHOULD provide the text personal
name of the recipient, if known, in a quoted phrase. The name must MUST be
in the form "last, first, mi." From [822]
Example:
To: "User, Sam S." <2145551213@mycompany.com>
Cc
Additional
The CC header contains additional recipients' fully-qualified domain address.
addresses. Many VM voice mail systems are not capable of storing or
reporting the full list of recipients to the receiver.
Vaudreuil Expires 11/5/95 [Page 6]
Internet Draft MIME Voice Profile May 5, 1995
Systems conformant to this profile may discard the CC
list of incoming messages as necessary. Systems conformant to this
profile should SHOULD provide a complete list of recipients when possible.
It is recommended that all addressees contain the text personal
name of the recipient, if known, in a quoted phrase. The name must MUST be
in the form "last, first, mi." From [822]
Example:
To: "User, Sam S." <2145551213@mycompany.com>
Systems conformant to this profile may discard the CC list of incoming
messages as necessary. Systems conformant 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, or the time specified by the originator if the message is
scheduled for deferred delivery. originator. Conforming implementations should SHOULD
be able to convert RFC 822 date and time stamps into local time. If the
VM reports message-sent time, the value in the Date field should be
used, not the time the message was received at the destination system.
From [822]
Example:
Date: Wed, 28 Jul 93 10:08:49 PST
Presentation of seconds and
The sending system MUST report the day of time the week is optional. 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 assumed when talking to
a voice system and
Vaudreuil Expires 9/1/95 [Page 7]
Internet Draft MIME Voice Profile March 21, 1995
should only SHOULD NOT be generated by a conforming implementation with per-
destination configuration.
implementation.
The Sender field often contains the name of an Internet-style mailing
list administrator and is the destination address for reporting errors
if the ESMTP MAIL FROM address is not available.
While it may not be possible to save this information in some VM 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
A
The Message-id header contains a unique per-message identifier. This value A
unique message-id MUST be generated for each message sent from a
conforming implementation.
The message-id is not required to be stored on the receiving system.
This identifier may MAY be used for tracking, auditing, and returning
read-receipt reports. From [822]
Example:
Vaudreuil Expires 11/5/95 [Page 7]
Internet Draft MIME Voice Profile May 5, 1995
Message-id: <12345678@mycompany.com>
Received
Special-purpose
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
header is useful for debugging when using an ASCII message reader or a
header parsing tool.
A conforming system must MUST add Received headers when acting as a gateway
and must not remove them. These headers may 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 is conformant to
the MIME message format specification. This header must be present in
any conforming message. Systems conformant to this the voice
messaging profile will MUST include a comment with the words "(Voice 1.0)".
From [MIME]
Example:
MIME-Version: 1.0 (Voice 1.0)
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
Vaudreuil Expires 9/1/95 [Page 8]
Internet Draft MIME Voice Profile March 21, 1995
representation suitable for that environment. The content-transfer-
encoding header describes this transformation if it is needed.
Conformant implementations MUST recognize and decode the standard
encodings, "Binary", "7bit, "8bit", "Base-64" and "Quoted-Printable".
The allowable content-transfer-encodings are specified in the next
section of this document. From [MIME]
Sensitivity
The sensitivity 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 conformant system
is prohibited
MUST prohibit the recipient from forwarding this message to any other
user. If the receiving system does not support privacy and the
sensitivity is one of "Personal" or "Private", the message must MUST be
Vaudreuil Expires 11/5/95 [Page 8]
Internet Draft MIME Voice Profile May 5, 1995
returned to the sender with an appropriate error message code indicating that
privacy could not be assured and that the message was not delivered.
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". This field can be used
Conformant implementations MAY use this header to indicate the
importance of a message and may order messages in a recipient's mailbox and is equivalent to the AMIS-
Digital Priority indication. From
mailbox. From: [X400]
Subject
The subject field is often provided by email systems but is not widely
supported on Voice Mail platforms. This field may MAY be generated by a
conforming implementation and may be discarded if present.
3 present by a
receiving system.
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 ("Base-64").
While Base-64 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 labled labeled as "Binary".
An implementation in conformance with this profile should SHOULD send audio
data in binary form when binary message transport is available. When
binary transport is not available, implementations must MUST encode the
message as Base-64. The detection and decoding of "Quoted-Printable",
"7bit", and "8bit" must also MUST be supported in order to meet MIME
Vaudreuil Expires 9/1/95 [Page 9]
Internet Draft MIME Voice Profile March 21, 1995
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 message to send multi-segment messages.
Message/RFC822 (REQUIRED)
MIME requires support of the Message/RFC822 message encapsulation body
part. This body part is used in the Internet to forward complete
messages within a multipart/mixed message. Processing of this body
Vaudreuil Expires 11/5/95 [Page 9]
Internet Draft MIME Voice Profile May 5, 1995
part entails trivial processing to unencapsulate/encapsulate decapsulate/encapsulate the
message. Systems conformant to this profile but should not SHOULD NOT send this body
part but must accepted MUST accept if in conformance with basic MIME. Specific
handling depends on the platform, and interpretation of this
content-type content-
type is left as an implementation decision. From [MIME]
Text/Plain (REQUIRED)
MIME requires support of the basic text/plain Text/Plain content type. This
content type has no applicability within the voice messaging
environment and should not be sent. Specific handling depends on
environment. Conformant implementations MUST NOT send the
platform, and interpretation of this content-type Text/Plain
content-type. Conformant implementations MUST accept Text/Plain
messages, however, specific handling is left as an implementation
decision. One option is to return the message to the sender with a
media-unsupported error code. From [MIME]
Multipart/Mixed (REQUIRED)
MIME provides the facilities for enclosing several body parts in a
single message. Multipart/Mixed may MAY be used for sending multi-segment
voice messages, that is, to preserve across the network the
distinction between an annotation and a forwarded message. Conformant
systems must MUST accept multipart/mixed body parts. Systems are permitted MAY to
collapse such a multi-segment message into a single segment if
multi-segment multi-
segment messages are not supported on the receiving machine. From
[MIME]
Message/Notification (REQUIRED)
This MIME body part is used for sending machine-parsable delivery
status notifications. Conformant implementations must use the
Message/Notification construct when returning messages or sending
warnings. Conformant implementations must recognize and decode the
Message/Notification content type and present the reason for failure
to the user. From [NOTIFY]
Multipart/Report (REQUIRED)
The Multipart/Report is used for enclosing a Message/Notification body
part and any returned message content. This body type is a companion
to Message/Notification. Conformant implementations must use the
Multipart/Report construct when returning messages or sending
warnings. Conformant implementations must recognize and decode the
Multipart/Report content type. From [NOTIFY2] [REPORT]
Audio/32KADPCM (REQUIRED)
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
Vaudreuil Expires 9/1/95 [Page 10]
Internet Draft MIME Voice Profile March 21, 1995
technique. This algorithm will be registered with the IANA for MIME
use under the name Audio/32KADPCM.
Support of Audio/32KADPCM is required for conformance with
Vaudreuil Expires 11/5/95 [Page 10]
Internet Draft MIME Voice Profile May 5, 1995
An implementation conformant to this
profile. profile MUST use Audio/32KADPCM
by default.
Proprietary Voice Formats (OPTIONAL)
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 encodings should be
registered as sub-types of Audio. The use of unregistered content-
type values is strongly discouraged.
Use of any other encoding except Audio/32KADPCM reduces
interoperability in the absence of explicit manual system
configuration. A system conformant to this profile will not send
proprietary voice formats without explict implementation MAY use any other encoding
with explicit per-destination configuration.
Multipart/VM (OPTIONAL)
Multipart/Voice-Message
This new MIME multipart structure provides a mechanism for packaging
the senders spoken name, a spoken subject and, the message. The
multipart provides for the packaging of three segments, the first is
the spoken name, the second is a spoken subject, and the third is the
message itself. Forwarded messages can be created by simply nesting
multiparts
multipart content-types (this is also possible with Multipart/Mixed if
spoken name or spoken subject is not present). This type is defined
in an appendix to this document.
An implementation conformant to this profile will use Audio/32KADPCM
by default. Use of any other encoding except Audio/32KADPCM reduces
interoperability in the absence of explicit manual system
configuration. A system conformant to this profile will not
Conforming implementations MUST send
other voice formats without explict configuration. the Multipart/Voice-Message if a
spoken name or spoken subject is available. Conforming
implementations SHOULD recognize the Multipart/Voice-Message and
separate the spoken name or spoken subject.
Vaudreuil Expires 9/1/95 11/5/95 [Page 11]
Internet Draft MIME Voice Profile March 21, May 5, 1995
5. Message Transport Protocol
Messages are transported between VM 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] was recently published and formalized an extension mechanism
for SMTP, and subsequent RFCs have defined 8-bit text networking,
binary networking, and extensions to permit the declaration of message
size for the efficient transmission of large messages such as multi-
minute voice mail.
A command streaming extension for high performance message
transmission has been defined. [PIPE] This extension reduces the
number of round-trip packet exchanges and makes it possible to
validate all recipient addresses in one operation. This extension is
optional but recommended.
The following sections list ESMTP commands, keywords, and parameters
that are required and those that are optional.
5.1 ESMTP Commands
HELO (REQUIRED)
Base SMTP greeting and identification of sender. This command is not
to be sent by conforming systems unless the more-capable EHLO command
is not accepted. It is included for compatibility with general SMTP
implementations. Conforming 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
gatewayed
received from a gateway or sent to an Internet-style mailing list.
Conforming implementations MUST implement the extended MAIL FROM
command. From [SMTP] [SMTP, ESMTP]
RCPT TO (REQUIRED)
Recipient's mailbox. This field contains only the addresses to which
the message should be delivered for this transaction. In the event
Vaudreuil Expires 11/5/95 [Page 12]
Internet Draft MIME Voice Profile May 5, 1995
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. Conforming implementations MUST
implement the extended RCPT TO command. From [SMTP]
Vaudreuil Expires 9/1/95 [Page 12]
Internet Draft MIME Voice Profile March 21, 1995 [SMTP, ESMTP]
DATA (REQUIRED)
Initiates the transfer of message data. This command is required to
be supported but should only be used data. Support for this command is
required in the event the binary mode command BDAT is not supported. supported by
the remote system. Conforming implementations MUST implement the SMTP
DATA command for backwards compatibility. From [SMTP]
TURN (DISCOURAGED)
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. This command Because SMTP is useful to poll for
messages.
(Note the security implications of using not an authenticated
protocol, the turn TURN command presents an opportunity to improperly fetch
mail queued for another destination. This fetching is possible
because of the lack of authentication of the sending VM by Conforming implementations
SHOULD NOT implement the
protocol). TURN command. From [SMTP]
QUIT (REQUIRED)
Requests that the connection be closed. If accepted, the remote
machine will reset and close the connection. Conforming
implementations MUST implement the QUIT command. From [SMTP]
RSET (REQUIRED)
Resets the connection to its initial state. Conforming
implementations MUST implement the RSET command. From [SMTP]
VRFY (OPTIONAL)
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. Conforming
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 (REQUIRED)
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. Conformant
implementations MUST implement the ESMTP command and return the
capabilities indicated later in this memo. From [ESMTP]
Vaudreuil Expires 11/5/95 [Page 13]
Internet Draft MIME Voice Profile May 5, 1995
BDAT (REQUIRED)
The BDAT command is an provides a higher efficiency alternative to the
earlier DATA command. command, especially for voice. The BDAT command provides
for native binary transport and does not require
encoding transport. Because voice data into 7-bit line-limited formats.
All other commands must be recognized and an appropriate error code
returned if not supported. From [BIN]
Vaudreuil Expires 9/1/95 [Page 13]
Internet Draft MIME Voice Profile March 21, 1995 messages are large binary
objects otherwise subject to BASE-64 encoding, BDAT will result in a
substantial improvement in transmission efficiency over DATA.
Conformant implementations SHOULD support binary transport using the
BDAT command.[BINARY]
5.2 ESMTP Keywords
STREAMING (OPTIONAL) Capabilities
The following ESMTP keywords indicate extended features useful for
voice messaging.
PIPELINING
The "STREAMING" "PIPELINING" keyword indicates ability of the receiving SMTP to
accept pipelined SMTP commands. Pipelining commands dramatically improves
the protocol performance over wide area networks. Conformant
implementations SHOULD support the command pipelining indicated by
this parameter. From [PIPE]
SIZE (REQUIRED)
The "SIZE" keyword provides a mechanism by which the receiving SMTP
can indicate the maximum size message supported. Conformant
implementations MUST provide the size capability and SHOULD honor any
size limitations when sending. From [SIZE]
CHUNKING (REQUIRED)
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. Conformant implementations SHOULD support binary
transport indicated by this capability. From [BIN] [BINARY]
BINARYMIME (REQUIRED)
The "BINARYMIME" keyword indicates that the receiver SMTP can accept
binary encoded MIME messages. Note that CHUNKING mode must be
supported for this option, but CHUNKING does not mean that Conformant implementations should
support binary
messages can be supported. transport indicated by this capability. From [BIN] [BINARY]
NOTIFY (REQUIRED)
The "NOTIFY" keyword indicates that the receiver SMTP will accept
explicit delivery status notification requests. From [DSN]
3 Conformant
implementations MUST support the delivery notification extensions in
[DSN].
5.3 ESMTP Parameters - MAIL FROM
BINARYMIME
Vaudreuil Expires 11/5/95 [Page 14]
Internet Draft MIME Voice Profile May 5, 1995
The current message is a binary encoded MIME messages. Conformant
implementations SHOULD support binary transport indicated by this
parameter. From [BIN]
4 [BINARY]
5.4 ESMTP Parameters - RCPT TO
NOTIFY
The NOTIFY parameter indicates the conditions under which a delivery
report should SHOULD be sent. Conformant implementations must honor this
request. From [DSN]
RET
Whether
The RET parameter indicates whether the content of the message should
be returned. Conformant systems SHOULD honor a request for returned
content. From [DSN]
6. Management Protocols
The Internet protocols provide a mechanism for the management of VM
machines,
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.
Vaudreuil Expires 9/1/95 [Page 14]
Internet Draft MIME Voice Profile March 21, 1995
6.1 Network Management
The digital interface to the VM and the TCP/IP protocols should SHOULD be
managed by the standard network Management Information Bases (MIBs).
managed. MIB II provides SHOULD be implemented to provide basic statistics and
reporting of the TCP/IP TCP and IP protocol
performance performance. [MIB II]
6.2 Directory and statistics. Media-specific MIBs are available Message Management
Conformant systems SHOULD provide for
X.25, Ethernet, FDDI, Token Ring, Frame Relay, and other network
technologies. This MIB provides necessary information to diagnose
faulty hardware, overloaded network conditions, and excessive traffic
conditions from a remote the management station.
Management of the machine resources and message
traffic and queue monitoring based on the host MIB and the Message and Directory MIB is recommended. MIB.
[MADMAN]
Vaudreuil Expires 9/1/95 11/5/95 [Page 15]
Internet Draft MIME Voice Profile March 21, May 5, 1995
7. 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., Klensin, J., "SMTP Service Extension for Command
Pipelining" Internet Draft <draft-freed-streaming-0?.txt>
[ESMTP]Klensin, <draft-ietf-mailext-pipelining-02.txt>
[ESMTP] Klensin, J., Freed, N., Rose, M., Stefferud, E., and D.
Crocker, "SMTP Service Extensions" RFC 1651, United Nations
University, Innosoft International, Inc., Dover Beach Consulting,
Inc., Network Management Associates, Inc., The Branch Office,
February 1993.
[SIZE] Klensin, J, Freed, N., Moore, K, "SMTP Service Extensions for
Message Size Declaration" RFC 1653, United Nations University,
Innosoft International, Inc., Inc., February 1993. February 1993.
[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 P., "Domain names - implementation and
specification", RFC1035, Nov 1987.
[DNS2] Mockapetris, P.,"Domain 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.
[BIN]
[BINARY] Vaudreuil, G., "SMTP Service Extensions for Transmission of
Large and Binary MIME Messages", Internet Draft <draft-vaudreuil- <draft-ietf-mailext-
binary-06.txt>
[NOTIFY] Vaudreuil, G., Moore, K., "An Extensible Message Format for
Delivery Status Notifications", Internet Draft <draft-ietf-notary-
mime-delivery-02-txt>
[NOTIFY2]
[REPORT] Vaudreuil, G., "Multipart/Report", Internet-Draft,
<draft-ietf-notary-mime-report-04.txt> <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>.
Vaudreuil Expires 9/1/95 11/5/95 [Page 16]
Internet Draft MIME Voice Profile March 21, May 5, 1995
[G721] CCITT Recommendation G.700-G.795 (1988), General Aspects of
Digital Transmission Systems, Terminal Equipments. Equipment. Blue Book.
[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.
8. Security Consideration
This document is a profile of existing Internet mail protcols. protocols. As
such, it does not create any security issues not already existing in
the profiled Internet mail protocols themselves.
9. Acknowledgements Acknowledgments
The author would like to offer special thanks to Glen Glenn Parsons/BNR for
his extensive review, helpful suggestions, and extensive editing
including the requirements matrix.
10. Author's Address
Gregory M. Vaudreuil
Octel Network Services
17080 Dallas Parkway
Dallas, TX 75248-1905
214-733-2722
Greg.Vaudreuil@ONS.Octel.Com
Phone/Fax: +1-214-733-2722
Greg.Vaudreuil@Octel.Com
Vaudreuil Expires 9/1/95 11/5/95 [Page 17]
Internet Draft MIME Voice Profile March 21, May 5, 1995
11. Appendix - MIME/ESMTP Voice Profile 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 personal name |4.2 | |x| | | |
To |4.2 |x| | | | |
Addition of text personal name |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 (Voice 1.0) |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| | |
Detection & Decoding inbound messages | | | | | | |
From |4.2 |x| | | | |
Utilize text personal name |4.2 | | |x| | | |
To |4.2 |x| | | | |
Utilize text personal name |4.2 | | |x| | |
CC |4.2 | | |x| | |
Utilize text personal name |4.2 | | |x| | |
Date |4.2 |x| | | | |
Conversion of Date to local time |4.2 | |x| | | |
Presentation of seconds & weekday |4.2 | | |x| | |
Sender |4.2 | | | |x| |
Message ID |4.2 | |x| | | | |
Received |4.2 | |x| | | |
MIME Version: 1.0 (Voice 1.0) |4.2 |x| | | | |
Content Type |4.2 |x| | | | |
Content-Transfer-Encoding |4.2 |x| | | | |
Sensitivity |4.2 |x| | | | |1
Vaudreuil Expires 9/1/95 11/5/95 [Page 18]
Internet Draft MIME Voice Profile March 21, May 5, 1995
Sensitivity |4.2 |x| | | | |1
Importance |4.2 | | |x| | |
Subject |4.2 | | |x| | |
| | | | | | |
Binary Content Encoding: | | | | | | |
Encoding outbound messages | | | | | | |
7BITMIME |4.3 | | | | |x|
8BITMIME |4.3 | | | | |x|
Quoted Printable |4.3 | | | | |x|
Base-64 |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| | | | |
Base-64 |4.3 |x| | | | |
Binary |4.3 |x| | | | |
| | | | | | |
Message Content Types: | | | | | | |
Inclusion in outbound messages | | | | | | |
Message/RFC822 |4.3 | | | |x| |
Text/plain |4.3 | | |x| | | |x|
Multipart/Mixed |4.3 | | |x| | |
Message/Notification |4.3 |x| | | |x| | |
Multipart/Report |4.3 |x| | | |x| | |
Audio/32KADPCM |4.3 |x| | | | |
Content-Description |4.3, 12 | | |x| | |
Content-Duration |4.3, 12 | | |x| | |
Content-Language |4.3, 12 | | |x| | |
Audio/* (proprietary encodings) |4.3 | | |x| | |
Multipart/VM |4.3, 13
Multipart/Voice-Message |4.3 |X| | | |x| | |
Detection & decoding in inbound messages | | | | | | |
Message/RFC822 |4.3 |x| | | | |
Text/plain |4.3 |x| | | | |
Multipart/Mixed |4.3 |x| | | | |
Message/Notification |4.3 |x| | | | |
Multipart/Report |4.3 |x| | | | |
Audio/32KADPCM |4.3 |x| | | | |
Audio/* (proprietary encodings) |4.3 | | |x| | |
Multipart/VM |4.3, 13
Multipart/Voice-Message |4.3 |X| | | |x| | |
| | | | | | |
Message Transport Protocol: | | | | | | |
ESMTP Commands | | | | | | |
EHELO
HELO |5.1 |x| | | | |
MAIL FROM |5.1 |x| | | | |
RCPT TO |5.1 |x| | | | |
DATA |5.1 |x| | | | |
TURN |5.1 | | | |x| | |x|
QUIT |5.1 |x| | | | |
RSET |5.1 |x| | | | |
VRFY |5.1 | | |x| | |
EHLO |5.1 |x| | | | |
BDAT |5.1 |x| | |x| | | |3
ESMTP Keywords | | | | | | |
Vaudreuil Expires 9/1/95 [Page 19]
Internet Draft MIME Voice Profile March 21, 1995
STREAMING |5.2 | | |x| | | |
SIZE |5.2 |x| | | | |
CHUNKING |5.2 |x| | |x| | | |
BINARYMIME |5.2 |x| | |x| | | |
Vaudreuil Expires 11/5/95 [Page 19]
Internet Draft MIME Voice Profile May 5, 1995
NOTIFY |5.2 |x| | | | |
| | | | | | |
Management Protocols: | | | | | | |
SNMP for message & network mgmt |6.0
Network management |6.1 | |x| | | |
MIBs for monitoring
Monitoring queues & resources |6.0 |6.2 | |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.
2. When binary transport is not available
3. When binary transport is available
Vaudreuil Expires 9/1/95 11/5/95 [Page 20]
Internet Draft MIME Voice Profile March 21, May 5, 1995
12. Appendix - Example Voice Message
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: "Parsons, Glen, Glenn, W." 2145551234@mv1.mycompany.com 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 1.0)
Content-type: Multipart/VM; Multipart/Voice-Message; Boundary = "MessageBoundary"
Content-Transfer-Encoding: 7bit
Message-ID: VM1.mycompany.co-123456789 VM2.mycompany.com-123456789
Sensitivity: Private
Importance: High
--MessageBoundary
Content-type: Audio/32KADPCM
Content-Transfer-Encoding: Base-64
glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
(This is a sample of the base-64 Spoken Name data) fgdhgd
jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gQ5tkjpokfgW
dlkgpokpeowrit09==
--MessageBoundary
Content-type: Audio/32KADPCM
Content-Transfer-Encoding: Base-64
glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
(This is a sample of the base-64 Spoken Subject data) fgdhgd
jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gQ5tkjpokfgW
dlkgpokpeowrit09==
--MessageBoundary
Content-type: Audio/32KADPCM
Content-Transfer-Encoding: Base-64
glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
(This is a sample of the base-64 message data) fgdhgdfwgd
jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gQ5tkjpokfgW
dlkgpokpeowrit09==
--MessageBoundary--
Vaudreuil Expires 11/5/95 [Page 21]
Internet Draft MIME Voice Profile May 5, 1995
13. Appendix - Audio/32KADPCM Content Type
Mime type name: Audio
Mime Sub-Type name: 32KADPCM
Required Parameters: None
Optional Parameters: None
Vaudreuil Expires 9/1/95 [Page 21]
Internet Draft MIME Voice Profile March 21, 1995
Encoding Considerations: Any encoding necessary for transport may be
used.
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.
No header information shall be included before the audio data. When
this subtype is present, a sample rate of 8000 Hz and a single channel
is assumed.
Vaudreuil Expires 9/1/95 11/5/95 [Page 22]
Internet Draft MIME Voice Profile March 21, May 5, 1995
13. Appendix - Multipart/VM Multipart/Voice-Message
Mime type name: Multipart
Mime Sub-Type name: Spoken-NameVM Voice-Message
Required Parameters: Boundary
Optional Parameters: None
Encoding Considerations: Quoted-Printable and Binary of 7 bit are sufficient. Base-64 and
Quoted-Printable are prohibited. prohibited on multipart content-types.
The syntax of a Multipart/VM Multipart/Voice-Message is identical to the
Multipart/Mixed content type. The VM Voice-Message content-type contains
three body parts. The first is an audio segment conatining containing the spoken
name of the originator, the second is an audio segment containing a
spoken subject, and the third is the voice message itself. Forwarded
voice messages can be created by simply nesting multiparts . multipart content
types.
The spoken name segment shall contain the name of the message sender
in the voice of the sender. The length of the spoken name segment
must not exceed 12 seconds. If no spoken name is available, the
segment must still be present but may be empty.
The spoken subject segment shall contain the subject of the message
sender in the voice of the sender. The length of the spoken subject
segment must not exceed 20 seconds. If no spoken subject segment is
available, the segment must still be present but may be empty.
The voice message body part may contain any arbitrary content
including a multipart/mixed collections of body parts, though will
typically be an audio segment.
The default handling of the multipart/VM Multipart/Voice-Message shall be to voice
the spoken-name segment and then the spoken-subject prior to
displaying or voicing the remainder of the message.
Vaudreuil Expires 9/1/95 11/5/95 [Page 23]
----