CUCM ad-hoc conference with thrird party SIP phone

[rajarshi.basak]

I have been trying to set up an ad-hoc conference with a third party sip-phone as a host. But I am getting 403 Forbidden with "unknown calling DN" after I send an Invite to conference factory URI to initiate the conference. From SIP trunk messaging guide, "The conference initiator calls the conference server using INVITE(Conference Factory URI) to begin a conference. The AS-SIP-EI conference factory URI lookslike @. The UCM routes the request via normal DA dialplan routing using confFactoryDigitString.". Any idea?

[dstaudt]

Third party SIP phones are not supported with the CUCM ad hoc conferencing mechanism (which is based on non-RFC standard SIP protocol extensions and behaviours).

The only type of conferencing that would be able to work would be RFC SIP standard conferencing, which is managed (including audio mixing) onboard the phone itself - in which case CUCM is not aware of the conference, and there are no interactions with the CUCM ad hoc conferencing feature.