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mesut ozcan

Cisco 9951 IP Phone Restart Problem

Hi all,

I am facing a strange issue.

When i made test call from 9951 phones to 3rd Party IVR system, phones restarted. But only 9951 phones.

If i check "MTP Required" field on IPPhone page, problem solved but this time 9951 phones could not make video calls                

Do you have any idea about this?  



Manish Gogna
Cisco Employee

Hi Mesut,

Does the 9951 phone reset everytime you call the 3rd party IVR?

Is it affecting only one 9951 or all of them?

Are other phone models also affected when calling the 3rd party IVR?

At what stage of the call is the phone reset?

For video to work on 99XX series IP phones MTP needs to be unchecked on the them, so it explains why the video does not work when you check MTP on 9951.


Hi Manish,

Video side is clear, i got it.

Your answers are kindly below;

- yes all 9951 phones reset everytime i called IVR system

- it is only affected 9951 phones, we also have 8945 and 6945 phones but there is no problem on that types.

(the only SIP working phones are 9951 in our deployment)

- phones reset at the first a couple of seconds after IVR prompt start

If we capture packets on the phone, i have seen lots of RTP packets coming from CUBE router.

As you see, this packets are malformed and CUBE router is where we host MTPs, XCoders and CFBs.



On your CUBE do you allow sip to sip calls, sip to h323, h323 to sip and h323 to h323 under voice services voip?

Best Regards

Hi Hermanus,

As you can see here, yes we allow all call scenarios.

allow-connections h323 to h323

allow-connections h323 to sip

allow-connections sip to h323

allow-connections sip to sip



Hi Mesut,

I am facing similar kind of issue..

did you find solution for your issue...

can you please share your solution.


Deval Tetar

That's pretty weird behavior. What is the cucm version and firmware version running on 9951's? Will need to check for any existing defects or known issues, else this will need packet captures and debugs from the phone for a test call to troubleshoot further.


Hi Manish,

CUCM Version :

9951 SW Release : sip9951.9-4-1-9

I laready have packet pactures, CUCM traces and console logs of a test calls btw.



Hi Mesut,

Maybe a silly question again, do you have a transcoder configured on your CUBE gateway and is that registered to your CUCM and in the MRL that the 9951 phones uses as well as your GW on your CUCM?



Best Regards

Hi again Hermanus,

Yes, there is two different transoder configured on CUBE and it is registered to CUCM.

They are also reachable by 9951s and GWs.



Looks similar to the following


9951 phone resets in specific condition using recording


This happens in the below situation:

9951 is connecting with UCCX script using G711

9951 has recording enabled using the BiB.

The  script is putting the call on hold (to transfer to an agent), when CUCM  sends a re-invite to connect the media between the MoH and the phone  the Phone replies with 200OK announcing G711 and G729.

When CUCM selects G729 (because of the region settings between MoH and Phone) the phone sends BYE and resets.


Use G.711 for region between Moh/Ann and Phone

Although the bug status is closed, can you verify if above conditions are met and try the workaround as listed above or by disabling recording on one of the 9951's and let us know if it works.


Hi Manish,

Thank you for this, but nothing changed.

I try to configure a new region for Ann/MoHs, use G711 between them and 9951s but reboot again.

Also use same region for 9951s and Ann/Mohs but after test calls, it is reboot again.



I would suggest engaging TAC at this point of time if no one else provides any inputs.


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