Ami,

I understand that the transport of any DS0 stream will require RTP transport.

The question has to do with Interworking vs. Transport. When the destination is an H.323 terminal, the DS0 streams that are part of an H.320 call must be converted from H.320 to H.323 in the gateway. However, if the destination is another H.320 terminal and the packet network is only an intermediate transport link, then it is better to transport each DS0 stream from the H.320 terminal individually rather than to interwork H.320 to H.323 to H.320 in both gateways.

I a carries is to use the packet network as transparent segments added to the existing network, then all services must be completely transparent to the end users.

Bob

------------------------------------------------------------------ Robert Callaghan Siemens Information & Communication Networks Tel: +1.561.997.3756 Fax: +1.561.997.3403 Email: Robert.Callaghan@ICN.Siemens.com ------------------------------------------------------------------

-----Original Message----- From: Ami Amir [mailto:amir@RADVISION.RAD.CO.IL] Sent: Wednesday, April 28, 1999 4:42 AM To: ITU-SG16@mailbag.cps.intel.com Subject: Re: Methods For Support of H.320/H.324

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?).

Ami

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

-----Original Message----- From: Callaghan, Robert [SMTP:Robert.Callaghan@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

may

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

H.320

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?

[[TomT]] 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

not

voice, and should be transported as 64Kbps clear?

[[TomT]] That's where the V.140 negotiation comes in.

Bob

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Robert Callaghan Siemens Information & Communication Networks Tel: +1.561.997.3756 Fax: +1.561.997.3403 Email: Robert.Callaghan@ICN.Siemens.com

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