Ad hoc conferences enable a Cisco Unified CM endpoint to escalate a point-to-point call into a three-way call. The endpoint creating the escalation must be a Cisco Unified CM registered device with the Hold and Conference softkeys enabled, but the receiving endpoints can be any device as long as Cisco Unified CM has a route to reach the device, which would include a Cisco Meeting Server web app or any SIP-based endpoint.
When an Ad hoc conference is triggered by an endpoint to escalate a point-to-point call into a three-way call.
HQ-CUCM sends an API request via HTTPS to the Cisco Meeting Server to set up a conference.
You can see from the event log of CMS that API user “admin” of HQ-CUCM created a new space (001229070002) and in the wireshark down you can see the call coming in from firstname.lastname@example.org. Look at the URI that has been dialed. Cisco UCM is dialing ″sip:email@example.com:5060″ / “sip:firstname.lastname@example.org”.
For the rest of users jsmith and jbrown, the HQ-CUCM sends also a SIP INVITE with ″sip:email@example.com:5060″ / “sip:firstname.lastname@example.org”.
How the Unified CM creates the space “001229070002” which is used as the user part of the URI it dials to join this conference?
Answer “The Unified CM will create a randomly generated meeting number for each adhoc conference”.
However if you have multiple Unified CM clusters using the same CMS for ad-hoc conferences, there’s a possibility two clusters could choose the same ID. To ensure this does not happen the value specified in this parameter is prefixed to the randomly generated number and the resulting value is used to generate the meeting ID on CMS.
The only why to influence this is by setting a prefix in the conference bridge settings in CUCM configuration. Then every meeting number starts with this prefix and then uses a random number.
From the HQ-CUCM edit the conference bridge and configure the Conference Bridge Prefix of 9.
Test once again the AdHoc conference. You can see from the event log of CMS that API user “admin” of HQ-CUCM created a new space that start with 9 (9001229070002).
Note: With Cisco CMS as the conference bridge,
Cisco Unified CM is dialing using the IP address of the Cisco Meeting Server and not the domain name “sip:email@example.com”.. Cisco Meeting Server doesn’t have inbound rules to match the IP address.
On cisco CMS. Navigate toConfiguration > Incoming calls and create new Call matching rule using the IP address of 10.1.5.20.