7911/7912 Call/Registration dropouts

[DMadrox87]

Good Morning!

I'm Dale and I have just started a Network Junior position and this is my first post here. :)

I have been given a little piece of work to do and I was just wondering if anyone can help me with the below?

Situation: 7911 / 7912 random call drop outs and device reregistration without warning. Calls stay connected but there is no voice. Phones will also randomly restart but get stuck on registering until the eth is pulled and reseated.

No other phones affected and doesnt seem to be an issue with every 7911 or 7912 we have inherited.

The Devices in question belonged to a Third Party on CUCM v4 and were registered to our call manager (v8.5) after an office move/merge of staff around 6 months ago. We know these Devices are old and it would probably be better to replace them but I just cant magic money out of thin air to replace what could be in excess of 250 devices.

Had a little Google but not really had any success with that and I cant seem to replicate the issue so testing different options has been quite difficult.

Device Defaults in CUCM 8.5 show the following Loads:

7911 on Load: SCCP11.9-4-2-1S

7912 on Load: CP7912080004SCCP080108A

Any help would be greatly appreciated if you could point me in the right direction. I will do my best to provide any information needed. 

Thanks all. :)

[Manish Gogna]

Hi,

If this is affecting only the 7911's and 7912's then most likely it is not an issue with cucm. A couple of things that can be tried / checked are:

1. Compare the switchport config of the 7911's and 7912's with other phone models that are working fine, check for any switchport or interface errors

2. Check if the issue is specific to a certain switch , device pool or location.

3.Check the application logs using RTMT to see the reason codes for device unregistration events

4. Try swapping a couple of these problematic phones with working phone models and see if the issue follows the phones or the switchport

If these do not help then most likely it will require deep dive into callmanager traces or packet captures from the phones when the issue is experienced.

Manish

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[DMadrox87]

Thank you Manish.

I will take a look again today, using your recommended triage steps and post some more information when I can.

In relation to point 2: I have noticed that this issue has only really affected a particular set of people since their move to one of our buildings. I have had a issues in other buildings but only around 3 to 5 devices that are scattered.

EDIT: In relation to point 4: We gave the users 6921s and have had no issues. < Just remembered...

Thanks again :)