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MCU conference problem



i have configured a permanent conference in MCU 4501 (software version: 4.2(1.43)) if any participant has a fail with his or her connection, video goes down but layout stays same, it means if there were 3 participants and one of them leaves (suddenly) conference, the rest of still watching him, but they only see a black window and name of participant. This not happen if call is finished normally. I have select every participant and click on "disconnect this participant" button to "fix" this problem.

How can i solve this issue?

Thanks in advance.

4 Replies 4

Adam Wamsley
Cisco Employee
Cisco Employee

Does the MCU correct the issues after any amount of time from the disconnect?


Under what conditions will a Cisco TelePresence MCU disconnect an IP session?

Other than when a ‘normal’ disconnection occurs (that is, when a participant chooses to disconnect), the MCU will only drop an endpoint from the conference when the TCP layer breaks down for some reason related to the network or the endpoint; for example, if an endpoint connected to a conference is suddenly powered down or its network cable is pulled out, or there is some other problem which means there is no network path between the endpoint and the MCU.


: the MCU describes dropping a call due to network problems as an H.245 network connection error.

The time between the start of the problem and the MCU removing the endpoint from the conference will be approximately 75 seconds.

The MCU will never terminate the IP connection in the case where there is no problem with the TCP connection between the endpoint and the MCU but for some reason the endpoint stops sending all UDP/RTP/RTCP packets etc. to the MCU.


Martin Koch

Its always good to test with the latest version as well, which would be 4.4

In addition, could you share some light how the call is made, sip, h323, if a call control like

cucm or vcs is present, what kind of remote endpoints are used, if any firewalls are in the path.

In short info about the whole deployment and the call scenario.

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Hi Martin,

Must i have a Cisco contract to MCU is upgraded? or i can download it without any restriction?

Thanks in advance.

Hello Juan!

Yes, do download the file you would need to have a valid service contract to be in place.

Its located here:

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