Internet Draft S. McRae Document: draft-ietf-vpim-ivm-00.txt Lotus Development Category: Standards Track G. Parsons Expires in six months Nortel Networks July 12, 2000 Internet Voice Messaging <draft-ietf-vpim-ivm-00.txt> 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 Internet mail as part of a unified messaging infrastructure. 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 some forms of communication. By permitting voicemail to be implemented in an interoperable way on top of Internet Mail, voice messaging and electronic mail need no longer remain separate, isolated worlds and users will be able to choose the most appropriate form of communication. This will also enable new types of device, without keyboards, to be used to participate in electronic messaging when mobile, in a hostile environment, or in spite of disabilities. McRae & Parsons Expires in Six Months [Page 1]
Internet Draft Internet Voice Messaging July 12, 2000 There exist unified messaging systems which will transmit voicemail messages over the Internet using SMTP/MIME, but these systems suffer from a lack of interoperability because various aspects of such a message have not hitherto been standardised. In addition, voicemail systems can now conform to the Voice Profile for Internet Messaging (VPIM v2 as defined in RFC 2421 [VPIM2]) when forwarding messages to remote voicemail systems, but 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, and it is not reasonable to expect a message forwarded from such a system via SMTP to the desktop to be usable by the recipient. The result is messages which cannot be processed by the recipient (e.g. because of the encoding used), or look ugly to the user. 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). Finally is explained how a client MAY provide a level of interoperability with VPIM v2. It is desirable that unified messaging mail clients also be able to fully 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. This definition is based on the VPIM v3 goals document [GOALS], which is being revised to reflect subsequent discussions. 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 references separate work on critical and primary content types [CRITICAL, PRIMARY] and Partial delivery notifications [PNDN] for Internet mail. Addressing issues are discussed in a related Internet draft [ADDRESS]. Independent work within the IETF is also addressing VPIM directory issues. Further information on VPIM v2 and related activities can be found at http://www.ema.org/vpim/. 3. Conventions Used in this Document McRae & Parsons Expires in Six Months [Page 2]
Internet Draft Internet Voice Messaging July 12, 2000 The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY" in this document are to be interpreted as defined in "Key words for use in RFCs to Indicate Requirement Levels" [KEYWORDS]. 4. Message Format All messages MUST conform with the Internet Mail format as it is being defined by the DRUMS working group [DRUMSIMF]. The message header SHOULD indicate a primary content type of "voice- message" (see [PRIMARY]). If the receiving user agent identifies the message as a voice message (from the primary content type), it MAY present it to the user as a voice message rather than as an electronic mail message with a voice attachment. Any content type is permitted in a message, but the top level content type on origination of a new, forwarded or reply voice message SHOULD be multipart/mixed. If the recipient is know to be VPIM v2 compliant then multipart/voice-message MAY be used instead (in which case all the provision of [VPIMV2] SHOULD be implemented]. If the message was created as a voice message, then the appropriate audio body part SHOULD be indicated as critical content, via a Content-Notification parameter of NOTIFY (see [CRITICAL]). Additional important body parts (such as the original audio message if a voicemail is being forwarded) SHOULD be indicated via a Content- Notification of PARTIAL. Contents which are not essential to communicating the meaning of the message (e.g. an associated vCard for the originator) SHOULD be indicated via a Content-Notification of IGNORE. The top level content type on origination of a delivery notification message MUST be multipart/report. 5. Transport The message MUST be transmitted in accordance with the Simple Mail Transport Protocol as it is being defined by the DRUMS working group [DRUMSMTP]. Delivery Status Notifications SHOULD be requested [DSN] if delivery of the message is important to the originator. 6. Addressing Any valid Internet Mail address may be used for a voice message. 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 McRae & Parsons Expires in Six Months [Page 3]
Internet Draft Internet Voice Messaging July 12, 2000 [SELECTOR]. Further discussion of addressing requirements for voice messages can be found in the VPIM Addressing draft [ADDRESS]. It is desirable to permit the use of a directory service to map between the E.164 phone number of the recipient and an SMTP mailbox address. How this might be achieved is currently under study in the VPIM and ENUM working groups [VPIME164]. 7. Notifications Delivery Status Notifications MUST be supported. All non-delivery of messages MUST result in a NDN, if requested [DSN]. If the receiving system is unable to process all of the media types within a voice message (indicated by the primary content type), then it SHOULD return a partial non-delivery report [PNDN]. Message Disposition Notifications SHOULD be supported (but according to MDN rules the user MUST be given the option of deciding whether MDNs are returned) [MDN]. If the recipient is unable to display all of the indicated critical content components indicated, then it SHOULD give the user the option of returning an appropriate MDN or MNDN (see [CRITICAL]). Editor's Note: at the time of writing, partial delivery MDNs are undergoing definition and there is no published draft. 8. Voice Contents Voice messages may be contained at any location within a message and MUST be contained in an audio/WAV content-type, unless the originator is aware that the recipient can handle other content. Specifically, Audio/32KADPCM MAY be used when the recipient is known to support VPIM v2 [VPIMV2]. The VOICE parameter from VPIM v2 [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 known, and indicated by the Content-Disposition as defined in VPIM v2 [VPIMV2]. A spoken subject MAY also be provided (per VPIM v2). An implementation MAY determine the recipient capabilities before the sending a message and choose a codec accordingly (e.g. using some form of Content Negotiation, which is an active area of investigation in the IETF). In the absence of such recipient knowledge, implementations MUST use MS-GSM within the WAV file - indicated via "audio/wav; codec=31". McRae & Parsons Expires in Six Months [Page 4]
Internet Draft Internet Voice Messaging July 12, 2000 Recipients MUST be able to play such a WAV encapsulated MS-GSM message, and MAY be able to play G.726 (indicated as audio/32kadpcm) to provide some 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 WAV with MS-GSM. An implementation MAY support interoperability with VPIM v2 [VPIMV2], in which case it MUST be able to record G.726 (indicated as audio/32kadpcm). These requirements may be summarised as follows: Codec No VPIM v2 Support With VPIM V2 Support Record Playback Record Playback ------ ------ -------- ------ -------- WAV/MS-GSM MUST MUST MUST MUST G.726 MAY MAY MUST MUST Other MAY MAY MAY MAY 9. Fax Contents Fax contents SHOULD be carried according to RFC 2532 [IFAX]. 10. Further Work The above text provides some guidelines as to how to ensure that a VPIM v2 message arriving on at a compliant mail system might be rendered useful to the recipient. However, a thorough investigation of interoperability with VPIM v2 is beyond the scope of this document (although, once it has been undertaken, the requirements herein should be reviewed in that light). Other areas which are candidates to be referenced from this document include: Content Negotiation (inc. RESCAP); the VPIM Directory work; Spoken Header fields (embedded or references); the inclusion of the originator's telephone number in the RFC822 header; and a consideration of interoperability with e-mail clients not supporting this specification. 11. Security Considerations It is anticipated that there are no additional security issues beyond those identified in VPIM v2. 12. References [ADDRESS] Parsons, G., "VPIM Addressing" <draft-ema-vpim-address-01.txt> [CRITICAL] Burger, E., Candell, E., "Critical Content of Internet McRae & Parsons Expires in Six Months [Page 5]
Internet Draft Internet Voice Messaging July 12, 2000 Mail" <draft-burger-vpim-cc-00.txt> [DSN] Moore, K., "SMTP Service Extension for Delivery Status Notifications" RFC 1891, January 1996. [DRUMSMTP] Klensin, J., "Simple Mail Transfer Protocol", <draft-ietf-drums-smtpupd-12.txt>, Work in Progress. [DRUMSIMF] Resnick, P., "Internet Message Format", <draft-ietf-drums-msg-fmt-08.txt>, Work in Progress. [IFAX] Masinter, L., Wing, D. "Extended Facsimile Using Internet Mail", RFC 2532, March 1999. [KEYWORDS] Bradner, S., "Key Words for use in RFCs To Indicate Requirement Levels", RFC 2119, March 1997. [GOALS] Di Silvestro, L., Miles, R., "Goals for VPIM v3", <draft-ema-vpimv3-goals-01.txt>, Work in Progress. [MIME] Freed, N., Borenstein, N., "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies", RFC 2045, November 1996. [PNDN] Burger, E., "Partial Non-Delivery Notification" <draft-ema-vpim-pndn-01.txt> [PRIMARY] Burger, E., Candell, E., "Primary Content of Internet Mail" <draft-burger-vpim-pc-00.txt> [SELECTOR] Allocchio, C., "Minimal PSTN address format in Internet Mail", RFC 2303, March 1998. [SIMPLEV3] Parsons, G., "Voice Profile for Internet Mail Version 3: A Simple Approach" <draft-ema-vpim-simplev3-01.txt> [VPIME164] Vaudreuil, G. "Voice Messaging Directory Service: Principles of Operation", <draft-vaudreuil-vpimdir-principles-00.txt>, Work in Progress. [VPIMV2] Vaudreuil, G., Parsons, G., "Voice Profile for Internet Mail - version 2", RFC 2421, September 1998. [VPIMV3] Vaudreuil, G., Parsons, G., "Voice Profile for Internet Mail - version 3", <draft-ema-vpimv3-00.txt>, Work in Progress. [VPIMVM] Vaudreuil, G., and Parsons, G., "VPIM Voice Message: MIME Sub-type Registration", RFC 2423, September 1998. McRae & Parsons Expires in Six Months [Page 6]
Internet Draft Internet Voice Messaging July 12, 2000 [WAVMGSM] Di Silvestro, L., Baribault, G., "Waveform Audio File Format MIME Sub-type Registration" <draft-ema-vpim-wav-00.txt>. Work in Progress. 13. Author's Address Stuart J. McRae Lotus Development 43 Seymour Gardens Twickenham United Kingdom TW1 3AR Phone: +44 208 891 1896 Fax: +44 1784 499 112 Email: stuart_mcrae@lotus.com Glenn W. Parsons Nortel Networks P.O. Box 3511, Station C Ottawa, ON Canada K1Y 4H7 Phone: +1-613-763-7582 Fax: +1-613-763-4461 Email: gparsons@nortelnetworks.com 14. Full Copyright Statement Copyright (C) The Internet Society (2000). All Rights Reserved. This document and translations of it may be copied and furnished 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. McRae & Parsons Expires in Six Months [Page 7]
