draft-ema-vpim-voicemsg-00.txt Internet Draft Stuart McRae Expires in six months Lotus Development October 22, 1999 Internet Voice Messaging Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 draft documents 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 "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. 1. Abstract This document provides for the carriage of voicemail messages over the Internet. The concept described in this document was originally called VPIM v3. This term has been dropped to reflect the fact that it is not a successor format to VPIM v2, but rather an alternative specification for a different application. 2. Introduction People naturally communicate using their voices, and this is preferable to typing for many forms of communication. Therefore, if voice messaging is standardised in Internet mail it will be possible for users to use this preferred means of communication, when appropriate, as well as enabling new devices without keyboards to be developed which allow users to participate in electronic messaging when mobile, or in a hostile environments, or in spite of disabilities. There are currently a number of implementations of systems which will transmit a voicemail messages over the Internet using SMTP/MIME. However these systems suffer from a lack of Internet Draft Internet Voice Messaging October 22, 1999 McRae Expires 4/22/2000 [Page 2] interoperability because various aspects of such a message have not hitherto been standardised. Specifically, there are three classes of solution of this form voicemail messages in an SMTP/MIME compliant e-mail system when received, subsequently allowing retrieval from a mail client or the telephone; unified messaging solutions which store voicemail currently in use: unified messaging solutions which save messages in a proprietary e-mail system which then get forwarded through a gateway to SMTP/MIME for Internet transmission; and voicemail systems conforming to the Voice Profile for Internet Messaging (VPIM v2 as defined in RFC 2421 [VPIM2]) for forwarding messages to remote voicemail systems. Note that VPIM v2 was designed to allow two voicemail systems to exchange messages - not to allow a voicemail system to interoperate with a desktop e-mail client. These solutions suffer from a lack of interoperability when an Internet mail recipient receives such a message because there is no standard definition for how a voicemail message should be represented in SMTP/MIME, resulting in messages which cannot be read by the recipient (because of the encoding used), or simply look ugly. This document therefore proposes a standard mechanism for representing a voicemail message within SMTP/MIME, and a standard encoding for the audio content, which unified messaging systems and mail clients MUST implement to ensure interoperability. By using a standard SMTP/MIME representation, and a widely implemented audio encoding, this will also permit most users of e-mail clients not specifically implementing the standard to still access the voicemail message. In addition, this document describes features an e-mail client SHOULD implement to allow it to display voicemail message in a more friendly, context sensitive way to the user, and intelligently provide some of the additional functionality typically found in voicemail systems (such as responding with a voice message instead of e-mail). This document is partly derived from VPIM v2 [VPIMV2], from an original proposal for VPIM v3 [VPIMV3], and from an a simple version of that specification [SIMPLEV3]. It is intended to be based on the VPIM v3 goals document [GOALS], as revised at subsequent meetings (this document is currently being revised and reissued). It is highly desirable that unified messaging mail clients also be able to interoperate with voicemail servers. This is possible today, providing the client implements VPIM v2 [VPIMV2] in addition to this specification, and uses it to construct messages to be sent to a voicemail server. Separate work may be undertaken in the VPIM Working Group to provide further interoperability between clients implementing this specification and voicemail systems implementing VPIM. Internet Draft Internet Voice Messaging October 22, 1999 McRae Expires 4/22/2000 [Page 3] For more information on VPIM v2 and the activities of the VPIM 3. Conventions Used in this Document working group, see "MAY" in this document are to be interpreted as defined in "Key words for use in RFCs to Indicate Requirement Levels" [KEYWORDS]. 4. Mes ge Format http://www.ema.org/vpim/. The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and All messages MUST conform with the Internet Mail format as described in DRUMS [DRUMS]. Any content type is allowed to be in a message. The top level content type on origination of a new, forwarded or reply message SHOULD be either multipart/mixed or sa multipart/related. Top level content of audio/wav MUST be supported for receipt, to interoperate with clients capable of generating suitably encoded voice content but not supporting this specification in full. The top level content type on origination of a delivery notification message MUST be multipart/report. Work is currently underway to define a mechanism to indicate the primary content type of a message (i.e. to characterise a message as being a voicemail message, rather than an e-mail with a WAV file attached). It is also desirable to identify critical contents (e.g. the voice message the use actually sent), as opposed to any subsidiary attachments, to ensure that these are not discarded. These two concepts could be indicated separately, or combined. This document will be updated once that work has generated an Internet Draft. An implementation MAY use the multipart/voice-message content type as described in [VPIMVM] to package audio content together as a voice message in a manner conformant with VPIM v2 [VPIMV2]. 5. Transport All transport MUST support Internet Mail transport (SMTP/ESMTP) as described in DRUMS [DRUMS]. 6. Addressing Any valid Internet Mail address MAY be used. It is desirable to be able to use and onramp/offramp for delivery of a voicemail message to a user, which will result in specific addressing requirements, based on service selectors as defined in [SELECTOR]. Further work on these requirements is in progress. Internet Draft Internet Voice Messaging October 22, 1999 McRae Expires 4/22/2000 [Page 4] It is desirable to permit the use of a directory service to map 7. Notifications DSN MUST be supported. All of messages MUST result the E.164 phone number of the recipient into an SMTP mailbox in a NDN. Partial (to indicate that one or more contents could not be address. How this might be achieved is currently under study. non-delivery DSNs stored/relayed by the receiving MTA) SHOULD be supported. MDN SHOULD be supported. Partial MDNs (to indicate that one or more contents could not be rendered) SHOULD also be supported. Work on defining partial MDNs and DSNs is currently in process. 8. Voice Contents Voice messages may be contained at any location within a message and MUST be contained in an audio/* content-type. The VOICE parameter described in [VPIMV2] SHOULD be used to identify the any spoken names or spoken subjects (as distinct from voice message contents). The originators and recipients spoken names SHOULD be included with messages as separate audio contents. If a vCard is also included these MAY be referenced from the vCard, or included inline with a vCard. External references SHOULD NOT be used. An implementation MAY determine the recipient capabilities before the sending of a message and choose a codec accordingly (e.g. Using Content Negotiation). In the absence of such recipient knowledge, implementations MUST use MS-GSM - indicated via audio/msgsm or "audio/wav; codec=31". [refs tbd] Recipients MUST be able to play such MS-GSM messages, and SHOULD be able to play G.726 (indicated as audio/32kadpcm) for interoperability with VPIM v2 [VPIMV2]. An implementation MAY be able to play messages encoded with other codecs (either natively or via transcoding) but MUST be able to record MS-GSM. An implementation MAY support interoperability with VPIM v2 [VPIMV2], in which case it MUST be able to play G.726 (indicated as audio/32kadpcm). 9. Fax Contents Fax contents SHOULD be carried according to RFC 2305 [tbd] 10. Compatibility with Voicemail Systems supporting VPIM Internet Draft Internet Voice Messaging October 22, 1999 McRae Expires 4/22/2000 [Page 5] Separate work will be undertaken to investigate mechanisms to improve interoperability with voicemail systems implementing VPIM v2, or successor specifications. 11. References [VPIMV2] Vaudreuil, G., Parsons, G., "Voice Profile for Internet Mail - version 2", RFC 2421, September 1998. [KEYWORDS] Bradner, S., "Key Words for use in RFCs To Indicate Requirement Levels", RFC 2119, March 1997. [MIME] Freed, N., Borenstein, N., "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies", RFC 2045, November 1996. [GOALS] Di Silvestro, Laile, "Goals for VPIM v3", , Work in Progress. [VPIMVM] G. Vaudreuil and G. Parsons, "VPIM Voice Message: MIME Sub-type Registration", RFC 2423, September 1998. [VPIMV3] Vaudreuil, G., Parsons, G., "Voice Profile for Internet Mail - version 3", , Work in Progress. [DRUMS] Resnick, P., "Internet Message Format Standard", , Work in Progress. [SIMPLEV3] Parsons, G., " Voice Profile for Internet Mail - Version 3: A Simple Approach" [SELECTOR] Allocchio, C., _Minimal PSTN address format in Internet Mail_, RFC 2303, March 1998. 12. Security Considerations TBD 13. Author's Address Stuart J. McRae Lotus Development 43 Seymour Gardens Twickenham, TW1 3AR, United Kingdom Phone: +44 181 891 1896 Fax: +44 1784 499 112 Email: stuart_mcrae@lotus.com Internet Draft Internet Voice Messaging October 22, 1999 McRae Expires 4/22/2000 [Page 6] 14. Full Copyright Statement This document and translations of it may be copied and furnished "Copyright (C) The Internet Society (1999). All Rights Reserved. to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE." Internet Draft Internet Voice Messaging October 22, 1999