Changing RTP audio port at SIP side and notifying H323endpoint

Discussion related to SIP / H.323 interworking issues
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zmechz
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Joined: Thu Apr 13, 2017 1:31 pm

Changing RTP audio port at SIP side and notifying H323endpoint

Post by zmechz »

Hi, I am developping a SIP <=> H323 gateway.
My test scenario has one cisco device talking H323 and another one talking SIP.
At some point, I put the call on hold, and when I resume the call, I need to create a new RTP audio port for the H323endpoint, so it can send its audio data.
I wrote the code to create that port and send an open logical channel notifying the H323 endpoint to use it. But it seems the H323endpoint keeps sending audio to the old RTP port, it ignores my "Open Logical channel" msg with the new port.
Does anybody know how could I make the H323endpoint send data to the new audio port?
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willamowius
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Re: Changing RTP audio port at SIP side and notifying H323endpoint

Post by willamowius »

If you close the old audio channel and open a new one with new ports, your method should work.

But since you build a gateway anyway, why not keep the audio channel open and let the gateway proxy the media so the H.323 side can keep using the original port ?

Regards,
Jan
Jan Willamowius
Founder of the GNU Gatekeeper Project
https://www.gnugk.org
https://www.willamowius.com (H.323 support)
zmechz
Posts: 2
Joined: Thu Apr 13, 2017 1:31 pm

Re: Changing RTP audio port at SIP side and notifying H323endpoint

Post by zmechz »

Hi Jan,

Thanks in advance.
The problem happens when I put the call on Hold for more than a minute.
In my configuration there is also a proxy between the H323Endpoint and the SIP device, and this proxy has a 1 minute timeout.
That said, when I put the call on Hold, it closes all logical channels, and after one minute the proxy drops this audio port.
When I resume the call, it tries to create the logical channels again, but the proxy rejects this port due to timeout.

Regards,
Caio
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