Subject: [Sipping] Q.931 bodies to SIP messages

From: Terry L Anderson <[email-masked]>
Date: Mon, 20 Aug 2001 15:21:56 -0400

I am interested in ISDN-SIP and ISDN-SIP-ISDN interworking and while
some translation of Q.931/ISDN information to/from SIP
headers/messages/responses are reasonably obvious and others are
suggested in the ISUP to SIP Mapping draft, there are additional Q.931
IEs that are important to interworking.  I have not been able to find a
complete solution to this in current RFC or drafts or work on this
indicated in the current work plan.  Although this is similar to the
work currently being done by the SIP-T design team there are some
differences due to the fact that Q.931 signaling will often be by
D-channel to a GW rather than in a separate MGC.

Is there work being done on this issue that I have not found?

Of course several Q.931 IEs have obvious translation to existing SIP
headers.  It may be useful to have some other Q.931 IEs translated to
new SIP headers if they would be of interest to proxies and application
servers in making routing decisions, billing, etc.  But signaling
transparency for the ISDN-SIP-ISDN case would also suggest that there be
the ability to carry Q.931 messages in the body of some SIP messages, as
is suggested for ISUP and QSIG.  This would require adding an
appropriate MIME type.

I am anxious to learn if any of this work is being done.  If not I am
willing to help work on the problem.

--
Waiting for the other shoe to drop but hoping its a one legged man.
------------------------------------------------------------
Terry L Anderson              mailto:[email-masked]
Tel:908.582.7013   Fax:908.582.6729
Lucent Technologies/INS/Voice Over IP Access Networks
Rm 2B-121, 600 Mountain Av, Murray Hill, NJ 07974
http://its.lucent.com/~tla (Lucent internal) http://www.gti.net/tla

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From: "RANJITH MUKUNDAN" <[email-masked]>
Date: Tue, 21 Aug 2001 13:51:42 +0530

Guess, this discussion has come up abt the right time!...
we are in the process of exploring the possiblity of supporting other
ISDN-like protocols (eg, DPNSS/DASS2) generically, on the lines of
ISUP/QSIG object support in SIP-T. The draft I guess, will be out soon -

with  liberal  plagiarisation from "the whole d*** draft"; we (that incl

Terry) could sync-up and try and accomadate as much 'generality' as
practically possible.

And yes, there was a lot of noise quite sometime back to try n make the
ISUP/QSIG draft a generic user part draft - though at that point it
didnt look very interesting/implementation-wise feasible...but then, I
dont hold the same view anymore :).

As for the fact that the D channel terminating on a GW and not an MGC
-shouldnt impact the architecture of how SIP-T transports objects as
MIME type as standard means (sigtran/iua) exist to backhaul isdn
q.921-users from the GW to the MGC.

Cheers,
Ranjith Mukundan
Wipro Technologies