Subject: [dispatch] Topic for DISPATCH: Alert-Info URNs

From: <[email-masked]>
Date: Mon, 14 Sep 2009 11:16:51 +0200

Mary, Gonzalo,

At the IETF-75 we had a presentation and a discussion in BLISS on the
"Alert-Info URNs" proposal, described in
http://tools.ietf.org/id/draft-alexeitsev-bliss-alert-info-urns-02.txt.
During the discussion, it was recommended to submit the work to DISPATCH
and to document the interop problems. 

So, we would like to propose this as a new topic for DISPATCH. 

The motivation for this work comes from interoperability problems when
SIP services require the semantic for a ring- / ringback-tone to be
transmitted in in a SIP-message.  

The RFC 3261 allows an UAS or proxy to provide a specific ring-
/ringback-tone as a reference (e.g. HTTP URI) which can be played to the
user in the Alert-Info header. This mechanism does not ensure
interoperability when there is no common understanding of the referenced
content (different countries or vendors, hearing impaired) or when the
user has his own tones configured in the end device. 

For interoperability of services as call waiting, call forwarding, blind
transfer, automatic callback, call hold or emergency annoncements sent
over PBX systems, a mechanism is needed which allows the UAs and proxies
to transmit an indication which contains the semantic of the rendering
instead of the rendering itself and allows the receiving UA to decide
about the concrete rendering. 

The charter proposal and the updated draft are to follow. 

Kind regards
Laura