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Cannot make a Telepresence call successfully over a SIP Trunk

Dear All,

I have set up a link between my CUCM with a Telepresence Exchange via a SIP Trunk to an SBC. Below is the setup

Endpoint(Mixture of CTS and Tandberg)-----CUCM Nigeria-------------SBC(UAE)-----------TPX(UAE)------------CUCMUAE----------Endpoint(CTS-series).

Endpoints registered to CUCM2 can call all endpoints registered to CUCM1 without issues, however, calls are initiated from endpoints registered to CUCM1 to endpoints registered to CUCM2, they ring continuously until they timeout(All endpoints are set on auto answer mode).

During the course of mt troubleshooting, I enabled early offer the SIP profile attached to the SIP trunk and I obserevd the behavior below.

With Early offer disabled

We can dial the CTMS in Dubai from CTS endpoints in Nigeria and join a Telepresence conference with both Audio and Video

We can dial the CTMS from TANDBERG endpoints but cannot join a conference

We cannot dial any endpoint at the Dubai end successfully, it keeps ringing till it times out.


With Early offer enabled

We can dial any endpoint in the UAE from the TANDBERG endpoints, Jabber for Windows and MAC or handheld devices

We cannot dial Telepresence conference in Dubai. CTS endpoints do not connect to the bridge, TANDBERG endpoints connect but they cannot send DTMF tones

We cannot dial any endpoint in the Dubai from CTS and TX endpoints.


Please, if you have any experience with issues like this, I will greatly appreciate your help






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