Cisco IP Phone 7912 Rebooting

[alexanderbird]

Hi,

I have a network of 5x 7940's, 1x 7960, 1x 7970 running from CME 8.6 on a 2811 router (Powered by a Catalyst 3550). They are running on their own VLAN away from the "PC" network.

These all work fine, I recently acquired a 7912 phone, this will register on the system fine and will make calls however after being on for about 30 seconds it will reboot for no reason, I have tried powering it from both the switch and with a Cisco PSU to no avail.

I have been scratching my head over it for weeks, does any one have any suggestions as to why?

Thanks

Alexander

[Manish Gogna]

Hi Alexander,

You can try connecting it to a different switchport first and see if the issue persists. If yes, try a fectory reset of the phone.

HTH

Manish

[alexanderbird]

Hi Manish,

I have tried numerous different ports on the switch and have tried factory resetting the phone (settings, network configuration, **2, yes) but to no avail.

Do you have any other ideas.

Thanks,

Alexander  

[Charles Hill]

Hello alexanderbird,

What firmware is the 7912 using?

Thanks.

[alexanderbird]

Hi,

Firmware version is 

CP7912080004SCCP080108A

Thanks

Alexander

[Manish Gogna]

If different ports, cables, factory reset have been tried and the issue is affecting only one phone then its most likely a faulty phone that needs a replacement.

HTH

Manish

[alexanderbird]

Hi Manish

I have since acquired another 2 7912's and they are both doing exactly the same, reboots randomly after a period time (30 seconds ish).
I have discovered that if they are not "registered" to the CME then they do not randomly reboot.

Thanks

Alexander

[Charles Hill]

Have you looked at the debug display, status messages, console logs on one of the 7912s?

Browse to the ip address of one of the 7912s and you will see console logs, core dumps, status messages and debug display under device logs.

Debug display may give you a clue.

Here is a sample debug from one of my phones.

Dec 25 10:01:47 26: Name=SEP8478ACEC834F Load=SCCP8941_8945.9-4-1-9 Last=Initialized

Apr 22 13:22:10 12: Name=SEP8478ACEC834F Load=SCCP8941_8945.9-4-1-9 Last=CM-reset-TCP

Apr 22 13:25:09 18: Name=SEP8478ACEC834F Load=SCCP8941_8945.9-4-1-9 Last=Failback

Apr 22 13:25:25 26: Name=SEP8478ACEC834F Load=SCCP8941_8945.9-4-1-9 Last=Initialized

Apr 22 13:29:12 12: Name=SEP8478ACEC834F Load=SCCP8941_8945.9-4-1-9 Last=CM-reset-TCP You may want to do a packet capture of one of the ports/7912 phones. Not sure if it will provide much useful information, but you can also try running a debug ephone register and debug ephone error on your cme.

[alexanderbird]

Hi,

I have tried the above, the 7912 does not appear to have all the logging features you discuss.

When I click the logs the only thing that appears is

SEP0013195158EB.cnf.xml

 in the middle of the screen

I have also browsed to the web interface of my 7970 and saw the logs you refer to - perhaps a newer phone feature.

Are the logs on the 7912 accessible any other way?

Thanks

Alexander

[Charles Hill]

Sorry about that.  I'll verify what's available on the 7912.

[alexanderbird]

Ok, well I think I have them working properly.

I am quite confused over my findings.

The problem proved to be the fact that the DHCP server for the VLAN was in fact running on a Mikrotik 2011 router.
I have moved the DHCP server to the 2811 router and rebooting stopped.

Any suggestions as to why this caused rebooting would be appreciate as it has me completely confused.

Many thanks for everyones help.

Thanks

Alexander

[smartnet Veracel]

Hi, I've been through the same problem and now Im sure about what it is, my phones use to reboot out of the blue, but our DHCP server have had no problems, your solution take me towards the same conclusion.

[Leo Laohoo]

If it's powered by the Catalyst 3550 then try changing the cable.  You could have a faulty cabling issue.