Consistently dropping calls 10-12 minutes


We are using the UCM6204, and are consistently getting dropped calls around the 10-12 minute mark. We have tried changing a lot of the settings over the last few months but with no luck. Here is the system:

w/ GXP2170s

Is there any small setting that maybe I have overlooked? Any help would be appreciated.


try expanding on the set up that you have… what is the firewall… voice carriage…are the calls dropping internally externally or what… too many variables and a lot of vagueness on your part that needs elaboration for this user forum in order to help you


You are running a recent, but not current firmware; in fact the firmware you are running has know security vulnerabilities and Grandstream has stated that everyone should upgrade to

Important Upgrade Note:

Firmware contains security improvement. Please upgrade to firmware immediately for security purpose. After upgrading, please change web access password for ALL users in UCM web UI->Maintenance->User Management page including super admin, admin and consumer users.


Okay I will


Internal calls are fine. Only external calls drop occasionally atleast a handful a week. SonicWall Firewall, all sip port rules handled, @scottsip What are some specific things that you need to know that would help?


how are they handled specifically…

upgrading firmware will only help with security of the ucm… your problem needs further diagnosis and examination…


I have asked my firewall manager to update me on this when he can. Is there any common settings that I can look at in the meantime that have to do with consistently dropping calls after a certain amount of time?


just packet capturing calls… during call failures


I agree this should be the only benefit…


I am working on this as we speak and hopefully will have something in the next few hours, most likely 2 hrs.


I emailed you the whole file. I am unexperienced with wireshark but this is an error I did see.


The reason for the drop is typically -

  1. The session timer is active and a response was not seen
  2. The system has a max call time set’
  3. The data thru the network is congested to the extent RTP packets fail to flow and one side or the other ends the call thinking the other side has gone off-line.


apart from the timeouts that have recommended you above to be verified, keep in mind another important problem, connectivity.
From some customers I had roughly your same problem, and I went crazy to understand the cause.
In the end, the cause was internet connectivity. In my case at random the PPOE went down for a few seconds, consequently in navigation no one notices anything, if at that moment there are ongoing conversations these obviously fall.
So check that you have stable connectivity.


Does the call actually disconnect? Or does it just lose audio?


On the SonicWall, did you -

  1. Disable source port re-writes on the outbound NAT policy?
  2. Did you disable SIP transformations?


be sure to change the UDP timeout on the sonic-wall to at least 120
and as mentioned already disable sip transformation which is the sip alg


Check which side sent BYE or Cancel. And sniff reason if it is there.