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MCU 4515 disconnecting endpoints

Hi folks,

I need your help again!

We have a Cisco 4515 MCU, TMS, VCR, VCS Control and a lot of Edge 95 MXP codecs. All systems are registered to VCS Control using SIP alone. TMS is managing all devices, including MCU and VCR. All of our conferences are created and managed via TMS.

This is our problem:

We create a conference via TMS, ok. All choosed endpoints are connected to the conference correctly. But unexpectedly, the MCU disconnects all endpoints without reason. It happens randomly, sometimes the conference takes several hours and the problem does not occur, sometimes it occurs after only 5 minutes of conference. That is a strange behavior, I was not able to say exactly what is causing the problem.

Look, I took these strange logs, seconds after the endpoint is connected:

Sem título.png

When the participant is disconnected, this message is showed in the eventlog page:

MCU 4515 erro 2.png

I don't know exactly what is causing the problem, but I have configured all systems to use H323 protocol instead SIP, and now, I don't have this problem anymore when use H323 protocol, the problem stops to occur.

We have no problem about packet loss, firewall, routing and etc, nothing. It's a great gigabit LAN.

Can anybody here help me? Our client is too much unsatisfied because of this problem. I need to find some solution.

Thank you!


Paulo Souza

Paulo Souza Was my response helpful? Please rate useful replies and remember to mark any solved questions as "answered".
New Member

MCU 4515 disconnecting endpoints

I think the key to this is the message "Ending call due to timeout of session timer" - in SIP calls there is a negoitated timer where one side must send an update message, and receive a reply, every so often to ensure the call is still alive. In this case it looks like the MCU doesn't hear back from the endpoint at the far end of the call before the timer expires, and so disconnects the call.

What I'd suggest you do is to try and reproduce this with just a single endpoint connected to the MCU, and get some logs of the SIP signalling at the MCU, VCS and the endpoint in question to see what happens to the required update messages when the call is dropped. This should hopefully point out what is happening to the SIP session refresh, and where you need to look more closely in order to resolve this.

New Member

Hi Paulo. Did you solve this

Hi Paulo. Did you solve this problem?. I am facing exactly the same issue.