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[AVT] 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
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Audio/Video Transport Working Group
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