IP PHONES - UCM Down/Features Disabled

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Mar 8th, 2010
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During a calls, phone will display 'UCM Down/Features Disabled', call gets dropped, reboots, and register again.

this keeps happening frequently.

Any resolutions on this?

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David Hailey Mon, 03/08/2010 - 15:09
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I dont know your particular environment but typically a phone will have at least 2 connections as such:

1 TCP connection to a primary server (this is a fully established session) for call control

2 TCP connection to a second server (this is a fully established session) for call control

If you are lucky enough to have tertiary failover, the phone can connect to a 3rd CUCM but the session is not active and has to be fully established for failover to occur.

Your phone can also failover to an SRST router.  This is similar to how tertiary failover works in most scenarios.

For you, when you see the UCM Down/Features Disabled this means the phone has lost connection to it's primary server.  If this is happening frequently and your phones drop and come right back up, you should look at RTMT to see if your phones are dropping from one server and re-registering to a secondary resource (and do they stay registered or do they eventually failback to the primary).  If so, you may want to check that you don't have a routing issue (i.e., flap) occurring on the network that is causing this issue.  You could also do a bug scrub to make sure you aren't running into a firmware issue on a particular version of phone.  However, I'd first take a look at how you have your CM groups and failover configured and look at connectivity between all voice servers and then all voice subnets (i.e., phones) to those servers.  If you find that you can isolate the issue to a particular server, you may have a bad NIC or even just CPU spike.  In that case, you could register phones to another server and see if the issue arises again.

Lastly, if this is on a number of phones - what I've said above would still go.  If it is only one phone, I'd go simple first and check the cabling from the phone to the switch and/or the switchport on the switch itself.


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esther.tan Mon, 05/24/2010 - 01:15
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Hi Hailey

I also face the same problem.

My question is why the phone will drop the call and do a quick reboot.  My understanding is when users see this error "CM down" on their phones when they are on the call, it should means call preservation is in progress while the phone actually lose the connection to the primary server. The call should not be dropped.


Harmit Singh Mon, 05/24/2010 - 01:35
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Hi Daniel / Esther,

Do the calls drop even when the call is within the system i.e. IP Phone to IP Phone or does this happen when the IP Phone is on a call with a PSTN party? If it happens when call is between IP Phone and PSTN, then that would ideally mean that the call preservation isnt correctly set up / enabled on the gateway.



David Hailey Mon, 05/24/2010 - 10:05
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It depends on what protocol you are using and also if you've configured things correctly for call preservation as well.  There is also typically a timer for how long calls can remain in this state without being dropped.  If the calls are dropping immediately then that's one thing.  There are a number of things that could be at play there in additiona to the protocol and configuration as mentioned above.  What are you experiencing and what are you using?


Richard McLoughlin Wed, 12/07/2016 - 04:19
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Hoping you are still active as this is an old thread. We are getting reports from a small number of users in one area which would indicate to me that it is more local to the affected individual than the Call Manager Cluster (CUCM 11.0 running on BE7KM platform supporting circa 3500 IP phones). We have huge problems with DAI, and port security which is another matter.

Really useful pointers for starters here but can I just clarify my understanding as correct:-

We are running SCCP on Cisco 7941/61s. Once a call is established between two telephone end points (IP phone to IP phone), the two end points maintain the network connectivity and the Call Manager subscriber is only involved in the initial setting and and then tearing down of the session. So even if a subscriber did fail causing the phones to register with their configured secondary or tertiary, the call itself shouldn't drop.

Kind regards


David Hailey Mon, 05/24/2010 - 12:21
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While that's all fine and dandy, this has nothing to do with the NetPro forums or the specific thread that you just overran with your manifesto.  Please do not post this sort of rant in the technical threads.


dmdafler1 Wed, 08/15/2012 - 12:47
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I am having the same issue,but only one telephone had the error pop up on the screen.



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