Methods For Support of H.320/H.324

Ami Amir amir at RADVISION.RAD.CO.IL
Wed Apr 28 04:41:45 EDT 1999

Hi Tom and Bob,

On the last question: There is no way that you can just tunnel DS0 channels
that are part of an H.320 call between two gateways over IP and expect it
to work. This statement is based on work we did in the pre-323 days, we
built a proprietary solution that really works.

Hence, the question is academic, and the DS0s always need to be converted
to RTP stream (or call it H.GCP contexts?).


-----Original Message-----
From:   Tom-PT Taylor [SMTP:taylor at NORTELNETWORKS.COM]
Sent:   Tuesday, April 27, 1999 2:40 PM
To:     ITU-SG16 at
Subject:        Re: Methods For Support of H.320/H.324

        -----Original Message-----
        From:   Callaghan, Robert [SMTP:Robert.Callaghan at ICN.SIEMENS.COM]
        Sent:   Monday, April 26, 1999 5:12 PM
        [[TomT]]  snip
> However, one major problem is only touched.  You stated the multi-DS0s
> be established using multi-link procedure.  To the network, these appear
> as
> individual calls.  The network will route the call such that it reaches
> the
> specified endpoint.  The network has no concept of routing multiple
> independent calls by the same path.  Since the gateway is only part of
> network, by what means can it be determined that the interworking of
> to H.323 will have all of the applicable DS0 connection at the same
> gateway?
> If they do not use the same gateway, how do the endpoints and gateways
> handle the connection?
         I agree that this is mysterious, but people must solve it now.
Thoughts of ISDN and wideband service go through my mind.  If it helps any,
I'll point out that we're really talking about an MCU rather than a Gateway
at this point.

> Another problem was not discussed.  If a H.320 connection arrives at the
> gateway, how does the gateway know that H.320 to H.323 interworking is
> required as opposed to the simple transport of the signal to another
> egress
> gateway?  As a corollary, how does the gateway know that the signal is
> voice, and should be transported as 64Kbps clear?
        That's where the V.140 negotiation comes in.

> Bob
> ------------------------------------------------------------------
> Robert Callaghan
> Siemens Information & Communication Networks
> Tel: +1.561.997.3756    Fax: +1.561.997.3403
> Email:  Robert.Callaghan at
> ------------------------------------------------------------------

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