Last Reset Reason: UCM-closed-TCP

[chuck47172]

CUCM  version 12.5

Phone Model: 8851

Firmware load sip88xx.12-8-1-0001-455

Question: Sometimes my phone will re-register for reason unknown. Phone application Admin Settings/Status/Network Statistics shows "Last Reset Reason: UCM-closed-TCP". What does that mean exactly? Where would I look to determine cause of random reset?

[balaji.bandi]

is the device and CUCM in the same network ?

[chuck47172]

No

[balaji.bandi]

if they are not same Lan, then your network connection issue, so keep monitoring the link which connect to CUCM is this stable ?

[Ritesh Desai]

Similar issue troubleshoot with customer having CUCM and IP Phones in different VLAN and IP Schema. Issue points to Network as highlighted by rest experts.

[Nithin Eluvathingal]

Looks like phone loose  connection with CUCM. you need to look in to the network. 

Very basic test will be a continuous ping from phone Vlan to CUCM.

[Tirtha Tripathy]

Hi Chuck,

UCM closed connection is the reason. That means Call Manager closed the TCP session.

Now why Call Manager closed the session can be seen in Call Manager logs only.

To find out, Enable SIP logs and SIP Registration logs of Call Manager. 

Then you will see that the keep alive message to UCM was missed from Phone to UCM or was post expiry time.

Hence the phone was re-registered.

This commonly happens if there is a firewall where SIP inspection is turned on.

I don't want to lead you into any conclusion but yes what ever is not Voice is all network... 
Now you have to prove, where in the network.

I have barely seen phone not sending keepalives. So that is not the cause. Now it is either not sending in the network or the UCM server is not able to process the keepalive before expiry timer.

UCM logs will only give more clarity. Just give a search with IP address and Call ID, it will detail the issue in the logs

Regards,

Tirtha

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