Network Working Group Greg Vaudreuil Internet Draft Octel Network Services Expires: September 1, 1995 March 21, 1995 MIME/ESMTP Profile for Voice Messaging Changes From the previous version 1) Discussion about interoperation between this profile and AMIS- Digital was deleted. Such a gateway is outside the scope of this document. 2) The Text/Signature body part 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 with Internet Directory services but is not expected to be completed in the near term. 3) The document was edited to reflect a clearer notion of what the role of this profile is. 4) IANA Registration of Audio/32KADPCM 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 the TURN command should function within the ESMTP framework. 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. 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 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 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 mail (VM) machines usually act as an integrated Message Transfer Agent and a User Agent. The VM 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 message stores are generally not capable of preserving the full semantics of an Internet message. As such, use of a VM 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. 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. Internet-style mailin Distribution lists are implemented as local alias lists. 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. 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 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 [Page 3] Internet Draft MIME Voice Profile March 21, 1995 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 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 [Page 4] Internet Draft MIME Voice Profile March 21, 1995 Message Format Profile The voice profile is based on and is consistent with the TCP/IP Email Protocol Suite with newly standardized options for enhanced functionality and performance. This section is an overview and profile of the necessary protocols as applied to the voice messaging environment. Message Addressing Formats RFC 822 and SMTP addressing 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 machine or node identification. These two components are separated by the commercial "@" symbol. The local part of the address is an ASCII string uniquely identifying a mailbox on a destination system. 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 to retain compatability 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 to lookup the fully-qualified domain name (FQDN) based on the address entered by the user. 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, 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 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 be designated for loopback testing. All messages sent to this mailbox must be returned back to the sender as a new message. The originating address should be "postmaster". Because VMs may use alpha-numeric addresses, 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. 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 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 originator's fully-qualified domain address (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. It is recommended that all messages contain the text personal name of the sender in a quoted phrase if available. The name must be 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 recipient's fully-qualified domain address. There may be one or more To: fields in any message. It is recommended that all addressees contain the text personal name of the recipient, if known, in a quoted phrase. The name must be in the form "last, first, mi." From [822] Example: To: "User, Sam S." <2145551213@mycompany.com> Cc Additional recipients' fully-qualified domain address. Many VM systems are not capable of storing or reporting the full list of recipients to the receiver. 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. It is recommended that all addressees contain the text personal name of the recipient, if known, in a quoted phrase. The name must be in the form "last, first, mi." From [822] Example: To: "User, Sam S." <2145551213@mycompany.com> Date 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. Conforming implementations 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 day of the week is optional. 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. 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 be generated by a conforming implementation with per- destination configuration. 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 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 unique per-message identifier. This value 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 Special-purpose 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 add Received headers when acting as a gateway and must not remove them. 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 is conformant to the MIME message format specification. This header must be present in any conforming message. Systems conformant to this profile will 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. 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 conformant system is prohibited 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 be returned to the sender with an appropriate error message 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 to order messages in a recipient's mailbox and is equivalent to the AMIS- Digital Priority indication. From [X400] Subject The subject field is often provided by email systems but is not widely supported on Voice Mail platforms. This field may be generated by a conforming implementation and may be discarded if present. 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 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 Base-64. The detection and decoding of "Quoted-Printable", "7bit", and "8bit" must also 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 part entails trivial processing to unencapsulate/encapsulate the message. Systems conformant to this profile but should not send this body part but must accepted if in conformance with basic MIME. Specific handling depends on the platform, and interpretation of this content-type is left as an implementation decision. From [MIME] Text/Plain (REQUIRED) MIME requires support of the basic text/plain content type. This content type has no applicability within the voice messaging environment and should not be sent. Specific handling depends on the platform, and interpretation of this content-type is left as an implementation decision. From [MIME] 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. Conformant systems must accept multipart/mixed body parts. Systems are permitted to collapse such a multi-segment message into a single segment if 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. 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. From [NOTIFY2] 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 this profile. 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 configuration. Multipart/VM (OPTIONAL) 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 (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 send other voice formats without explict configuration. Vaudreuil Expires 9/1/95 [Page 11] Internet Draft MIME Voice Profile March 21, 1995 Message Transport Protocol Messages are transported between VM 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. 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 or sent to an Internet-style mailing list. From [SMTP] 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 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. From [SMTP] Vaudreuil Expires 9/1/95 [Page 12] Internet Draft MIME Voice Profile March 21, 1995 DATA (REQUIRED) Initiates 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. 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 is useful to poll for messages. (Note the security implications of using the turn command to fetch mail queued for another destination. This fetching is possible because of the lack of authentication of the sending VM by the protocol). From [SMTP] QUIT (REQUIRED) Requests that the connection be closed. If accepted, the remote machine will reset and close the connection. From [SMTP] RSET (REQUIRED) Resets the connection to its initial state. 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. 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. From [ESMTP] BDAT (REQUIRED) The BDAT command is an alternative to the earlier DATA command. The BDAT command provides for binary transport and does not require encoding 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 ESMTP Keywords STREAMING (OPTIONAL) The "STREAMING" keyword indicates ability of the receiving SMTP to accept pipelined SMTP commands. From [PIPE] SIZE (REQUIRED) The "SIZE" keyword provides a mechanism by which the receiving SMTP can indicate the maximum size message supported. 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. From [BIN] 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 binary messages can be supported. From [BIN] NOTIFY (REQUIRED) The "NOTIFY" keyword indicates that the receiver SMTP will accept explicit delivery status notification requests. From [DSN] 3 ESMTP Parameters - MAIL FROM BINARYMIME The current message is a binary encoded MIME messages. From [BIN] 4 ESMTP Parameters - RCPT TO NOTIFY The conditions under which a delivery report should be sent. From [DSN] RET Whether the content of the message should be returned. From [DSN] Management Protocols The Internet protocols provide a mechanism for the management of VM machines, 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 The digital interface to the VM and the TCP/IP protocols should be managed by the standard network Management Information Bases (MIBs). 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. Vaudreuil Expires 9/1/95 [Page 15] Internet Draft MIME Voice Profile March 21, 1995 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 [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 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. [BIN] Vaudreuil, G., "SMTP Service Extensions for Transmission of Large and Binary MIME Messages", Internet Draft [NOTIFY] Vaudreuil, G., Moore, K., "An Extensible Message Format for Delivery Status Notifications", Internet Draft [NOTIFY2] Vaudreuil, G., "Multipart/Report", Internet-Draft, [DSN] Moore, K. "SMTP Service Extensions for Delivery Status Notifications", Internet Draft . Vaudreuil Expires 9/1/95 [Page 16] Internet Draft MIME Voice Profile March 21, 1995 [G721] CCITT Recommendation G.700-G.795 (1988), General Aspects of Digital Transmission Systems, Terminal Equipments. Blue Book. 8. Security Consideration This document is a profile of existing Internet mail protcols. As such, it does not create any security issues not already existing in the profiled Internet mail protocols themselves. 9. Acknowledgements The author would like to offer special thanks to Glen Parsons/BNR for his extensive review, helpful suggestions, and extensive editing including the requirements matrix. Author's Address Gregory M. Vaudreuil Octel Network Services 17080 Dallas Parkway Dallas, TX 75248-1905 214-733-2722 Greg.Vaudreuil@ONS.Octel.Com Vaudreuil Expires 9/1/95 [Page 17] Internet Draft MIME Voice Profile March 21, 1995 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 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| | | | | Vaudreuil Expires 9/1/95 [Page 18] Internet Draft MIME Voice Profile March 21, 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| | | Multipart/Mixed |4.3 | | |x| | | Message/Notification |4.3 | | |x| | | Multipart/Report |4.3 | | |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 | | |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 | | |x| | | | | | | | | | Message Transport Protocol: | | | | | | | ESMTP Commands | | | | | | | EHELO |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 | | | | | | | 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| | | | | BINARYMIME |5.2 |x| | | | | NOTIFY |5.2 |x| | | | | | | | | | | | Management Protocols: | | | | | | | SNMP for message & network mgmt |6.0 | |x| | | | MIBs for monitoring queues & resources |6.0 | |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 [Page 20] Internet Draft MIME Voice Profile March 21, 1995 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, W." 2145551234@mv1.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; Boundary = "MessageBoundary" Content-Transfer-Encoding: 7bit Message-ID: VM1.mycompany.co-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-- 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 [Page 22] Internet Draft MIME Voice Profile March 21, 1995 13. Appendix - Multipart/VM Mime type name: Multipart Mime Sub-Type name: Spoken-NameVM Required Parameters: Boundary Optional Parameters: None Encoding Considerations: Quoted-Printable and Base-64 are prohibited. The syntax of a Multipart/VM is identical to the Multipart/Mixed content type. The VM content-type contains three body parts. The first is an audio segment conatining 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 . 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 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 [Page 23]