VPIM Voice Message
MIME Sub-type Registration
Status of this Memo
This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
Copyright © The Internet Society (1998). All Rights Reserved.
This document describes the registration of the MIME sub-type multipart/voice-message for use with the Voice Profile for Internet Mail (VPIM). A full description of usage can be found in the VPIM v2 specification.
This document describes the registration of the MIME sub-type multipart/voice-message for use with the Voice Profile for Internet Mail (VPIM). A full description of usage can be found in the VPIM v2 specification [VPIM2]. This document revises an earlier sub-type registration in RFC 1911 [VPIM1].
2. VPIM Scope
The VPIM specification defines a restricted profile of the Internet multimedia messaging protocols for use between voice processing platforms. These platforms have historically been special-purpose computers and often do not have the same facilities normally associated with a traditional Internet Email-capable computer. As a result, VPIM also specifies additional functionality as it is needed. The profile is intended to specify the minimum common set of features to allow interworking between compliant systems.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [REQ].
3. Voice Message Interchange
The MIME sub-type multipart/voice-message is defined to hold specific media contents that are interchanged in messages between voice messaging systems described in [VPIM2]. Essentially, the sub-type provides a simple wrapper that easily identifies the entire content as being the components of a single voice message. The sub-type is identical in semantics and syntax to multipart/mixed, as defined in [MIME2]. As such, it may be safely interpreted as a multipart/mixed by systems that do not understand the sub-type (only the identification as a voice message would be lost).
This mechanism allows the insertion of an explanatory preamble (e.g. VPIM voice message attached) for recipients who read the message with pre-MIME software, since the preamble will be ignored by MIME- compliant software.
In addition to the MIME required boundary parameter, a version parameter is also required for this sub-type. This is to distinguish, this refinement of the sub-type from the previous definition in [VPIM1]. The value of the version parameter is "2.0" if the content conforms to the requirements of [VPIM2]. Should there be further revisions of this content type, there MUST be backwards compatibility (i.e. systems implementing version n can read version 2, and systems implementing version 2 can read version 2 contents within a version n). The default version value (when the parameter is missing) is 1, indicating the content conforms to the requirements of [VPIM1].
[VPIM2] describes the restriction that only specific media types, applicable to voice messaging, are valid `next-level' contents of this sub-type (when version=2.0). They are: audio/*, image/*, message/rfc822 and application/directory. The multipart provides for the packaging of as many of these contents as is necessary.
3.2 VPIM v2 Usage
The multipart/voice-message sub-type is a primary component of the VPIM specification [VPIM2]. All VPIM Messages MUST contain this sub-type to identify the wrapping of a voice message. The contents of this wrapper can vary from only one audio/32KADPCM content to a complex set of related and nested contents.
Typically, if more than one audio segment is present, the first is the spoken name of the originator, the second is the spoken subject, and the third is the voice message itself. This order, however, MUST NOT be assumed in any case. Further, the order that the contents appear SHOULD be the order in which they are presented to the user.
The spoken name segment, if available, 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.
The spoken subject segment, if available, 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.
The directory information part, if present, will contain information specific to the orginator of the voice message.
Refer to the VPIM v2 Specification for details on proper usage.
4. IANA Registration
To: email@example.com Subject: Registration of MIME media type multipart/voice-message
MIME media type name: multipart
MIME subtype name: voice-message
Required parameters: boundary, version
The use of boundary is defined in [MIME2]
The version parameter that contains the value "2.0" if enclosed content conforms to [VPIM2]. The absence of this parameter indicates conformance to the previous version defined in RFC 1911 [VPIM1].
Optional parameters: none
Encoding considerations: 7bit, 8bit or Binary
This definition identifies the content as being a voice message. In some environments (though likely not the majority), the loss of the anonymity of the content may be a security issue.
Systems developed to conform with [VPIM1] may not conform to this registration. Specifically, the required version will likely be absent, in this case the recipient system should still be able to accept the message and will be able to handle the content. The VPIM v1 positional identification, however, would likely be lost.
Applications which use this media type:
Primarily voice messaging
Magic number(s): ? File extension(s): .VPM Macintosh File Type Code(s): VPIM
Person & email address to contact for further information:
Glenn W. Parsons Glenn.Parsons@Nortel.ca Gregory M. Vaudreuil Greg.Vaudreuil@Octel.Com Intended usage: COMMON
Glenn W. Parsons & Gregory M. Vaudreuil
5. Authors' Addresses
Glenn W. Parsons Northern Telecom P.O. Box 3511, Station C Ottawa, ON K1Y 4H7 Canada Phone: +1-613-763-7582 Fax: +1-613-763-4461 EMail: Glenn.Parsons@Nortel.ca Gregory M. Vaudreuil Lucent Technologies 17080 Dallas Parkway Dallas, TX 75248-1905 United States Phone/Fax: +1-972-733-2722 EMail: GregV@Lucent.Com
[MIME2] Freed, N., and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types ", RFC 2046, November 1996. [MIME4] Freed, N., Klensin, J., and J. Postel, "Multipurpose Internet Mail Extensions (MIME) Part Four: Registration Procedures", RFC 2048, November 1996. [VPIM1] Vaudreuil, G., "Voice Profile for Internet Mail", RFC 1911, February 1996. [VPIM2] Vaudreuil, G., and G. Parsons, "Voice Profile for Internet Mail - version 2", RFC 2421, September 1998. [REQ] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
7. Full Copyright Statement
Copyright © The Internet Society (1998). All Rights Reserved.
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