[AVT] RE: Clearmode / VoIP Media Gateways supporting ISDN data

["Chong, Koan S, ALVAP" <kschong@att.com>]

I've forwarded your email to the ITU-T SG11  mailing list. Would be glad to receive further guidance. Thanks.
Regards,
Koan S. Chong
+1-732-420-4557

-----Original Message-----
From: Kreuter Ruediger [mailto:ruediger.kreuter@siemens.com]
Sent: Tuesday, October 15, 2002 8:45 AM
To: avt@ietf.org
Cc: 'danny@tcb.net'; Chong, Koan S, ALVAP
Subject: Clearmode / VoIP Media Gateways supporting ISDN data


Hi,

in August I published draft-kreuter-avt-rtp-clearmode-00.txt
with the intention to drive a IANA registration for a Codec
that can be used to support ISDN data connections via RTP.
The main application for that are VoIP media gateways 
replacing a TDM network.

This registration will have an influence on all VoIP media 
gateways and related softswitches in the converged network 
market, at least in interworking cases. Therefore I would 
like to get some comments by suppliers of such gear.
Do you agree with this draft (besides from typos :-) ? 
Are there concurrent solutions in the market/field ?

*********************************************************

Another topic to be discussed, 
is a discussion input for a "Coding of SDP Media Description 
Lines from TMR/USI", in case of "Call Interworking from BICC/
ISUP to SIP" (ITU, Study Group 11, WP3, Meetings of BICC/SIP 
interworking in Ottawa, Canada, 9th - 13th September 2002).

This ITU standardization input, recommends to use UDP for 
Nx64kbit/s unrestricted connections. ("64kbit/s unrestricted" 
or "transparent mode" are synonyms for "clearmode")
In SDP this would look like:

b=AS:64
m=data <port> udp

This approach leads to two questions:

Is it a good idea to transport ISDN data in VoIP networks 
directly on top of UDP instead of RTP ?
This would enforce to rebuild all features which currently 
are based on RTP/RTCP parameters; e.g. synchronization 
(time stamps) or statistics & billing (RTCP sender/receiver 
reports).

And is it necessary to support Nx64kbit/s (with N>1) 
within draft-kreuter-avt-rtp-clearmode-00.txt ? 
That is, is TDM:Nx64kbit/s visible to a VoIP media 
gateway ?
In that case an additional parameter describing the 
size of N would be needed, and an algorithm describing
the packetization in case of N>1.

Any opinions according this topic ?

Regards

Ruediger Kreuter
ruediger.kreuter@siemens.com

_______________________________________________
Audio/Video Transport Working Group
avt@ietf.org
https://www1.ietf.org/mailman/listinfo/avt