“You have 101 untouched email messages, one urgent message”
“You have no skipped email messages”
“You have four messages flagged urgent two”
“You have two answered messages”
“You have no deleted messages”
“This is the end of your email inbox”
“This was the complete message summary”.It is interesting to note that the same XML script can be used by a graphic
application to paint the graphic user interface, showing the folders for e-mail,
voice, fax, and video mail, with subfolders for normal and priority mail, and
the respective icons for normal, urgent, skipped, and deleted messages.
This example shows clearly why looking at the messaging summary dis-
played on a Web page is preferable to listening to the same information on a
phone.
Retrieval of Messages
As mentioned, voicemail can be retrieved either using a SIP UA (such as a SIP
phone, a PC or some mobile device), by using e-mail or a Web page and a
media player.
Summary
SIP can support all forms of messaging in universal messaging systems, as
well as supporting the specific requirements for voicemail that matches the
voicemail features in legacy TDM systems. The use of the Internet allows the
integration of messaging for all media (such as text, voice, fax, and video) in a
consistent fashion, while giving the user the options of retrieving messages on
various devices, ranging from the PC to the simple phone.
References
[1] “Unified Messaging Using SIP and RTSP” by H. Schulzrinne and K. Singh.
IP Telecom Services Workshop, Atlanta, Georgia, September 11, 2000.
[2] “Real-Time Streaming Protocol (RTSP)” by H. Schulzrinne, A. Rao, and R.
Lanphier. RFC2326, IETF, April 1998.
[3] “Guidelines for Usage of the SIP Caller Preferences Extension” by J. Rosen-
berg and P. Kyzivat: Internet Draft, IETF, October 2005, work in progress.
[4] “Control of Service Context Using SIP Request-URI” by B. Campbell and R.
Sparks. RFC 3087, IETF, April 2001.
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