Voice Profile for Internet Mail
RFC 1911

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• 03

Network Working Group                                       G. Vaudreuil
Request for Comments: 1911                        Octel Network Services
Category: Experimental                                     February 1996

                    Voice Profile for Internet Mail

Status of this Memo

   This memo defines an Experimental Protocol for the Internet
   community.  This memo does not specify an Internet standard of any
   kind.  Discussion and suggestions for improvement are requested.
   Distribution of this memo is unlimited.

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 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.

2. 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 functionally for conformant

Vaudreuil                     Experimental                      [Page 1]
RFC 1911                   MIME Voice Profile              February 1996

   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 limitations 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 machines usually act as an integrated Message
      Transfer Agent and a User Agent.  The voice mail machine 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 voice
      mail machine for general message forwarding and gatewaying is not
      supported.  Storage of "Received" lines and "Message-ID" may be
      limited.

      4) Nothing in this document precludes use of a general purpose
      email gateway from providing these services.  However, significant
      performance degradation may result if the email gateway does not
      support the ESMTP options recommended by this document.

      5) Internet-style mailing lists are not generally supported.
      Distribution lists are implemented as local alias lists.

      6) 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.

      7) 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.

Vaudreuil                     Experimental                      [Page 2]
RFC 1911                   MIME Voice Profile              February 1996

   It is a goal of this effort to make as few restrictions and additions