RFC 1911 (rfc1911) - Page 4 of 22

Voice Profile for Internet Mail

RFC 1911                   MIME Voice Profile              February 1996


   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.

4. Voice Message Interexchange Format

   The voice message interchange format is a profile of the Internet
   Email Protocol Suite.  It requires components from the message format
   standard for Internet messages [RFC 822], the Multipurpose Internet
   Message Extensions [MIME], the X.400 gateway specification [X.400],
   and the delivery report specifications [DRPT][STATUS].

4.1 Message Addressing Formats

   The RFC 822 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 global machine
   identification.

   The local part of the address shall be an ASCII string uniquely
   identifying a mailbox on a destination system.  For voice messaging,
   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 identifiers to
   retain compatibility with the limited 10 digit telephone keypad.

   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 voice mail machine to lookup the fully-
   qualified domain name (FQDN) based on the address entered by the
   user.  The mapping of dialed address to final destination system is
   generally accomplished through implementation-specific means.

   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



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