Network Working Group Greg Vaudreuil
Internet Draft Tigon Corporation
Expires: 10/25/94 April 25, 1994
MIME/ESMTP Profile for
Voice Messaging
<draft-umig-mime-voice-00.txt>
ToDo:
1) Fix Bibliography, Make References in Text
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 have 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 interconnect these machines.
The following document is a profile of the Internet standard MIME
and EXMTP 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.
2.Scope and Design Goals
MIME is the Internet multipurpose, multimedia messaging standard.
This document explicitly recognizes these capabilities and
provides a mechanism for the exchange of various messaging
technologies including voice and facsimile.
It is not a goal to make the interoperation of the earlier X.400
based AMIS-Digital and this profile possible by the use of a
standard X.400 to MIME gateway. While the message encodings and
messages semantics are similar, the addressing and routing are
not. The X.400 based AMIS-Digital addressing format is
Internet Draft Voice Profile April 25, 1994
sufficiently customized that it cannot be mapped to the RFC 822
mail format in the standard manner. The voice profile is
necessarily incompatible because it is intended to use the
standard TCP/IP mail addressing formats.
It is a goal of this effort to make as few protocol changes to
the existing Internet mail protocols as possible while satisfying
the user requirements for Voice Networking. 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. Using the native capabilities of
the internet mail system most user requirements listed in the
appendix can be met.
This specification is intended for use on a TCP/IP network.
While it is possible to use these protocols for simple point to
point networking, the specification is 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.
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. This 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, the Simple Mail Transport Protocol, RFC 822, the Standard
for the format of ARPA Internet Messages, RFC 1521 and RFC 1522,
the Multipurpose Internet Mail Extensions, RFC 1425 and RFC 1427,
Extensions to the SMTP protocol (ESMTP), and RFC 882 and RFC 883,
the Domain Name System. Where additional functionality is
needed, it will be defined in this document or in an appendix.
3.Protocol Restrictions
The number of recipients per message is not limited by this
protocol. Where possible implementations should not restrict the
number of recipients that can be received in a single message.
The maximum message length is not limited by this protocol.
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. (Units are in bytes, not minutes which can vary by
encoding format.)
4.Framework for the voice profile
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This document specifies a profile of the TCP/IP multi-media
messaging protocols for use by special purpose voice processing
platforms. These platforms are not general purpose computers and
often do not have facilities normally associated with an Internet
Email capable computer.
The following are typical restrictions imposed by a voice
messaging platform.
1) Text messages are not normally received and often cannot be
displayed or viewed in the normal fashion. They can be
processed only via advanced text-to-speech or text-to-fax
features not currently present in these machines.
2) Voice mail machines act as an integrated Message Transfer
Agent and a User Agent. The VM is responsible for final
delivery and there is no forwarding of messages. RFC 822
header fields have limited use in the context of the simple
messaging features currently deployed.
3) Voice mail message stores are generally not capable of
preserving the full semantics of an Internet Message. As
such, use of a VM for general message forwarding and
gatewaying is not supported. Storage of Received lines and
Message-ID may be be limited.
4) Internet style mailing lists are not generally supported.
Distribution lists are implemented as local alias lists.
5) There is generally no human operator. Error reports must be
machine parsable so helpful responses can be given to users
whose only access mechanism is voice.
6) The system user names are limited to 16 or fewer numeric
characters.
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5.Message Format Profile
The voice profile was written to be based on and be consistent
with the TCP/IP Protocol Suite as amended to support specific
services not provided in the TCP/IP protocol suite. This section
is intended to be an overview of the necessary protocols and a
profile of the applicable protocols as applied to the voice
messaging environment.
5.1. Message Addressing Formats
RFC 822 and SMTP addressing use 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
machine or node identification. These two components are
separated by the commercial @ symbol.
The local part is an ASCII string uniquely identifying a mailbox
on a destination system. It is required to be unique with the
system of networked voice mail machines. The local part is
defined to be a printable string containing the mailbox number of
the originator or a recipient. Administration of this number
space is expected to be conformant with national or corporate
telephone numbering plans.
The domain part of the address is a hierarchical global name for
all machines. 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 be
administered by a company or service provider. For participation
in the international Internet network, or for integration within
a corporate internet, each voice mail (VM) machine is required to
be given a unique domain name.
For example, a compliant message may be 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 to translate the dialed address to the fully qualified
domain name (FQDN). The mapping of dialed address to VM
destination 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, the use of 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.
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Postmaster@domain
By convention, a special mailbox named postmaster
should 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. This is not normal
on a voice processing platform and the specific
handling of these messages is up to specific
implementation.
Loopback@domain
A special mailbox name named "loopback" should be
designated for loopback testing. All messages sent
to this mailbox must be returned back to the sender
address. Because VMs do not use alpha-numeric
addresses, this will not conflict with any internal
numbering plan. Internal to VM, a specific numeric
address for DTMF entry can be mapped to "loopback".
Note that the loopback address can be abused to
route messages through a third party VM to avoid
toll charges. It is recommended that the loopback
feature be disabled except when testing the
networking between machines.
5.2. 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 are not used
to 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 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
The originators fully qualified domain address.
(This is a mailbox number 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.
Example: 2145551212@mycompany.com
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To
The recipient's fully qualified domain address.
There may be one or more To: fields in any message.
All recipients of a message must be listed in To
lines except when a recipient is specifically
intended to receive a blind carbon copy. Note that
many voice mail systems have no facilities for
storing or for reporting to the recipient the list
of recipients. These systems will generally discard
these headers when received.
It is recommended that all messages contain the text
personal name of the sender and the personal name of
the recipient in comment fields if available.
Cc
Additional recipients fully qualified domain
address. This field has no meaning beyond "To:" in
a VM and is not to be generated by an conforming
implementation. It is included for processing by the
receiver for compatibility with general Internet
mail agents which may not restrict the use of this
field.
If the VM supports the reporting of multiple
recipients, all names in the To: and Cc: fields
should be reported.
Date
The date, time, and time zone the message was
composed by the originator or the time specified by
the originator if the message is scheduled for
delayed delivery. Conforming implementations must
be able to convert RFC 822 date and time stamps into
local time. If the VM reports message sent time,
the value in this field should be used, not the time
the message was received at the destination system.
Example: Wed, 28 Jul 93 10:08:49 PDT
Sender
The actual address of the originator if the message
is sent by an agent on behalf of the author
indicated in the From: field.. This field is not to
be generated by an conforming implementation. It is
included for processing by the receiver for
compatibility with general internet mail software
which may generate this header.
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The sender field often contains the name of a
Internet style mailing list administrator and is the
address to report errors in the event that the ESMTP
MAIL FROM address is not available. While it may
not be possible to save this information in some
Voice Mail machines, discarding this information or
the SMTP MAIL FROM address will make it difficuly to
send a error message to the proper destination.
Message-id
A unique per-message identifier must be included by
the originator for every message. Conforming systems
must use an identifier constructed by concatenating
with a dash the sending VMs FQDN and a 8 digit
serial message number which is unique on the sending
system. This identifier will be used for tracking,
auditing, and returning delivery reports.
Example: mycompany.com-12345678
Received
Received headers are special purpose trace
information added to the beginning of a RFC 822
message by message transport agents. This is the
only header which is permitted to be added by a MTA.
These headers are useful for debugging when using an
ASCII message reader or a header parsing tool. A
conforming system must add received headers when
acting as a gateway. These headers must not be
removed by a system when acting as a gateway. These
headers may be ignored or deleted when the message
is received at the final destination.
MIME Version
The Mime-Version: 1.0 header indicates that the
message is conformant to the RFC 1341 message format
specification. It must be present in any conforming
message. From RFC 1341
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. From RFC 1341
Content-Transfer-Encoding
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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 this environment. The content-
transfer-encoding header describes this
transformation if needed. From RFC 1341
Sensitivity
This field indicates the requested privacy. If this
field exists, regardless of the selected case
insensitive value "Personal" or "Private". If no
privacy is requested, this field is omitted.
If a sensitivity header is present in the message,
an conformant system is prohibited from forwarding
this message. 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
message indicating that privacy could not be assured
and the message was not delivered.
The specific privacy values do not need to be
offered individually to users, but can be set on a
system wide basis.
Importance
This field 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 to order messages in a
recipients mailbox and is equivalent to the AMIS
Priority indication.
5.3. 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 [RFC-MIME]. MIME also provides for encoding binary
data in such a manner that it can be transported over the 7 bit
text oriented SMTP protocol. This transport encoding is
independent of the audio encoding that is designed to generate a
binary object.
MIME defined two transport encoding mechanisms, 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. A null encoding of "Binary" was
specified for use in an environment where binary transport is
available.
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An implementation in conformance with this profile is required to
send audio data encoded as binary where binary message transport
is available. Where binary transport is not available,
implementations must encode the message as Base-64. As required
by MIME, and to preserve interoperability with the fullest range
of possible devices, the detection of and decoding of quoted-
printable must also be supported.
The following content-types are profiled. Note that each of
these contents can be sent individually in a message or wrapped
in a multipart message to send multi-segment messages.
The following content types are identified for use with this
profile.
Audio/Basic(RECOMMENDED)
Audio/Basic was defined as 64Kbps u-law in the base
MIME protocol document. Support of Audio/Basic is
recommended for compatibility with current Internet
workstations but not required for conformance with
this profile.
Message/RFC822 (REQUIRED)
MIME requires support of the Message/RFC822 message
encapsulation body part. This body part is used in
the internet for forwarding complete messages within
a multipart/mixed message. Processing of this body
part entails trivial processing to unencapsulate-
encapsulate the message. It is not to be sent by a
system conformant to this profile but must be
accepted for conformance with basic MIME.
Text/Plain (REQUIRED)
MIME requires support of the basic text/plain
content type. This content has no applicability
within the voice messaging environment and should
not be sent. Behavior upon receipt of such a type
is dependent upon the platform and interpretation of
such a part is left as an implementation decision.
Options include dropping the body part and sending a
delivery report indicating the lack of support,
text-to-speech, and text-to-fax support.
Multipart/Mixed (REQUIRED)
MIME provides the facilities for enclosing several
body parts in a single message. Multipart/Mixed 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. Systems are permitted to collapse such a
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multi-segnemt message into a single segment if they
are not supported on the receiving machine.
Text/Signature (RECOMMENDED)
Text/Signature provides a mechanism for the sending
of per-user directory information including the
spoken name and the supported mailbox capabilities.
When used with a caching mechanism, basic directory
services with entries for commonly used entries can
be maintained. This body part is to be used to
support spoken name confirmation and ASCII name for
dial-by-name applications. The Text/Signature can
be included with a message using the multipart/mixed
constructor type. From <draft-vaudreuil-sig-02.txt
Message/Notification (REQUIRED)
This new MIME body part is used for sending delivery
status notifications. From <draft-ietf-notary-
delivery-00.txt>
Multipart/Notification (REQUIRED)
The Multipart/Delivery-Notification is used for
enclosing a text/delivery-notification body part and
any returned message content. This body type is a
companion to and is defined with the text/delivery-
report. Systems may optionally send a text
description
Audio/ADPCM (REQUIRED)
CCITT Draft Recommendation G.721 describes the
algorithm recommended for conversion of a 64 KB/s A-
law or -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. This
algorithm will be registered with the Internet
Assigned Numbers Authority for MIME use under the
name Audio/ADPCM.
ADPCM is widely available. Support of Audio/ADPCM is
required for conformance with this profile.
Proprietary Voice Formats (OPTIONAL)
Proprietary voice encoding formats are supported
under this profile provided a unique identifier is
registered with the IANA prior to use.
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Note that use of proprietary encodings reduces
interoperability in the absence of system
configuration.
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6.Message Transport Protocol (ESMTP)
Messages are transported using the Internet Extended Simple Mail
Transport Protocol. This protocol is used to send messages
between voice mail machines. 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. 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.
RFC 1425 was recently published and formalized an extension
mechanism for SMTP and subsequent RFCs have defined 8 bit text
networking and extensions to permit the declaration of message
size for the efficient transmission of large messages such as
multi-minute voice mail.
Binary transport is currently under development in the IETF.
When completed, the binary extensions to ESMTP will be required
for conformance with this profile. The current version of this
protocol is available in the public Internet Drafts directories
in the file <draft-ietf-vaudreuil-binary-02.txt>
A command streaming extension for high performance message
transmission is under development in the IETF. This extension
reduced 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. This document is
available in the public Internet Draft directories in the file
<draft-ietf-freed-streaming-00.txt>
The following ESMTP commands may be supported.
6.1. ESMTP Commands
HELO (REQUIRED)
Base SMTP greeting and identification of sender.
This 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.
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 in the event
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that the message was gatewayed or sent to a Internet
style mailing list.
RCPT TO (REQUIRED)
Recipients 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.
DATA (REQUIRED)
The command to initiate the transfer of message
data. This command is required to be supported but
should only be used in the event the binary mode
command BDAT is not supported.
TURN (RECOMMENDED)
The turn command requests a change-of-roles, that
is, the client which opened the connection offers to
assume the role of server for any mail the remote
machine may which to send. This is useful to poll
for messages.
(Note the security implications of using the turn
command to fetch mail queued for another
destination. This is possible due the lack of
authentication of the sending VM by the protocol)
QUIT (REQUIRED)
QUIT requests that the connection be closed. If
accepted, the remote machine will reset and close
the connection.
RSET (REQUIRED)
Reset the connection to the initial state.
VRFY (OPTIONAL)
The VRFY command requests verification that the
listed recipient is reachable by this node. 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.
(Note that the implementation may simplify the
guessing of a recipients mailbox or automated sweeps
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for valid mailbox addresses resupting 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.)
EHLO (REQUIRED)
EHLO is an enhanced mail greeting which enables a
server to announce the support for extended
messaging options. The extended messaging modes are
discussed in a later section.
BDAT (REQUIRED)
Initiate binary data transmission
The BDAT command is an alternative to the earlier
DATA command. The BDAT command does not require
encoding voice data into 7 bit line limited formats.
<draft-vaudreuil-binary-01.txt>
All other commands must be recognized and an appropriate error
code returned if not supported.
6.2. ESMTP Keywords
STREAMING (Optional)
The streaming keyword indicates the ability of the
receiving SMTP to accept pipelined SMTP commands.
(from Internet Draft <draft-freed-streaming-01.txt>
SIZE (Required)
The size indication provides a mechanism by which
the receiving SMTP can indicate the maximum size
message supported. (from RFC 1427)
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. (from Internet-Draft <draft-
vaudreuil-binary-01.txt>
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 that CHUNKING does not mean that binary
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messages can be supported. (from Internet-Draft
<draft-vaudreuil-binary-02.txt>
6.3. ESMTP Parameters - MAIL FROM
BINARYMIME The binarymime parameter indicates that the current
message is a binary encoded MIME messages.
6.4. ESMTP Parameters - RCPT TO
NOTIFY The notify parameter specifies the conditions under
which a delivery report should be sent. From <draft-
ietf-notary-smtp-drpt-01.txt>
RET The ret parameter indicates whether the content of
the message should be returned. From <draft-ietf-
notary-smtp-drpt-01.txt>
PRIORITY This parameter indicates the requested priority to
be given by the transmission network. From <draft-
vaudreuil-priority-00.txt>
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7.Management Protocols
The Internet protocols provide a mechanism for the management of
voice mail machines, from the management of the physical network
through the management of the message queues. SNMP should be
supported on a compliant message machine.
The digital interface to the VM and the TCP/IP protocols should
be managed. MIB II provides basic statistics and reporting of
the TCP/IP protocol performance and statistics. Media specific
MIBS are available 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 management station.
Management of the machine resources and message queue monitoring
based on the host MIB and the Message and Directory MIB is
recommended but not required for conformance with this profile.
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8.References
[MIME]Borenstein, N., and N. Freed, "Multipurpose Internet Mail
Extensions", RFC 1521, Bellcore, Innosoft, Sept 1993.
[MSG] Crocker, D., "Standard for the Format of ARPA Internet
Text Messages", STD 11, RFC 822, UDEL, August 1982.
3. Freed, N., "SMTP Service Extension for Command Pipelining"
Internet Draft Work in Progress - 10/19/93.
4. Klensin, J., Freed, N., Rose, M., Stefferud, E., and D.
Crocker, "SMTP Service Extensions" RFC 1425, United Nations
University, Innosoft International, Inc., Dover Beach Consulting,
Inc., Network Management Associates, Inc., The Branch Office,
February 1993.
5. Klensin, J, Freed, N., Moore, K, "SMTP Service Extensions
for Message Size Declaration" RFC 1427, United Nations
University, Innosoft International, Inc., Inc., February 1993.
February 1993
6. 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.
7. Mockapetris, P.,"Domain names - implementation and
specification", RFC1035, Nov 1987.
8. Mockapetris, P.,"Domain names - concepts and facilities",
RFC 1034, Nov 1987.
9. Postel, J., "Simple Mail Transfer Protocol", STD 10, RFC
821, USC/Information Sciences Institute, August 1982.
10. Vaudreuil, G., "Text/Signature", Internet Draft Work-in-
Progress - 11/22/93.
11. Vaudreuil, G., "SMTP Service Extensions for Transmission
of Large and Binary MIME Messages", Internet Draft Work-in-
Progress - 11/10/93.
12. Vaudreuil, G., "An Extensible Message Format for Delivery
Status Notifications", Internet Draft Work-in-Progress -
11/22/93.
9.Security Consideration
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10. Author's Address
Gregory M. Vaudreuil
The Tigon Corporation
17080 Dallas Parkway
Dallas, TX 75248-1905
214-733-2722
Gvaudre@cnri.reston.va.us
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11. Appendix - Example Voice Message
The following message is a full featured, all options enabled
message. It is addressed to two receipients. The message includes
the senders spoken name and a short speach segment. The message
is marked as important and private. read receipts and positive
delivery acknowledgement are requested.
To: 2145551212@vm1.mycompany.com
To: 2145551234@mv1.mycompany.com
From: 2175552345@VM2.mycompany.com
Date: Mon, 26 Aug 93 10:20:20 CST
MIME-Version: 1.0 (Voice Profile Version 1)
Content-type: Multipart/Mixed; Boundary = "MessageBoundary"
Content-Transfer-Encoding: 7bit
Return-content: Full
Message-ID: VM1.mycompany.co-123456789
Sensitivity: Private-if-Possible
Generate-Receipt-Notification:
Generate-Delivery-Notification:
Importance: High
--MessageBoundary
Content-type: Text/Signature
Name: User, Joe, R. (Joe Random User)
SpokenName: lslfdslsertiflkTfpgkTportrpkTpfgTpoiTpssdasddasdasd
(This is the base-64 encoded spoken name)
o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90geQ5tkjpokfgW
dlkgpokpeowrit09IpokporkgwI==
Capabilities: Audio/Basic, Audio/ADPCM, Application/Signature,
Image/G3Fax
--MessageBoundary
Content-type: Audio/ADPCM
Content-Transfer-Encoding: Base-64
glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
(This is a sample of the base-64 message data) fgdhgdfgd
jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gQ5tkjpokfgW
dlkgpokpeowrit09==
--MessageBoundary--
Vaudreuil Expires 10/25/94 [Page 19]
Internet Draft Voice Profile April 25, 1994
12. Appendix - Example ESMTP Transaction
The following ESMTP transaction represents the successful sending
of a simple message to a system which does not support extended
transport modes. Non-ESMTP protocol events are noted in Italics.
ESMTP commands and significant significant replies are in Bold.
Except for the replies to the EHLO command, the text following
the reply code is optional.
Sender Receipient
Wait for TCP
Connection
Initiate TCP Connection to Port 25
Accept TCP
Connection
220 ready
EHLO vm1.mycompany.com
250-hello
250 SIZE 100000
MAIL FROM: <2145551212@vm1.some.com>
250 Address OK
RCPT TO: <2145551234@vm2.some.com>
250 Address OK
DATA
354 Send Message
To: 2135551234@vm2.some.com
From: 2145551212@vm1.some.com
MIME-Version: 1.0
Content-Type: Audio/ADPCM
Content-Transfer-Encoding: Base64
JFsdfjlkdjflkjsd lfflskjslkfjslfkjlsk
ksdjlksjlfksjflkjsljsldkfjlskfjlskjff
lkjsdlkfjslkdjflskksjfsdfsdf=
.
250 OK
QUIT
250 Goodby
Receiver closes TCP
connection