downstream PC reboot makes phone reboot

[shane]

I have a strange issue with what appears to be most or all of my phones. When a PC is plugged into the back of a phone and the PC reboots it reboots the Phone also. I am using Dell PC's. Any ideas?

[kthorngr]

You didn't mention the phone load you are using or the type of phone that is experincing this issue.

You could be running into this issue:

CSCed52164 - CVL: 7960 reboots when PC ethernet port is unplugged and plugged in

Kev

[zcude]

Hello, I'm an engineer with the saem company working on the problem and here's the progress so far.

We've run both 6.0.3 and 6.0.4 loads on our 7940 and 7960 phones and the problem still occurs.

The specific problem is that when the phones PC port comes UP, whether from computer rebooting OR another switch being plugged into the back of it, the phone reboots after about 10 seconds. Ran a trace on the LAN Switch side of the phone and couldn't see anything wrong, just the normal phone reboot traffic with it releasing and renewing it's Ip address and other assorted phone traffic. If you're curious I can email you the ethereal trace if you think I'm missing something, but it looked pretty vanilla to me. The phones are plugged into Dell switches (boo-hiss, I know) but we have other sites running these same models and they're staying up fine.

Zach

[Erick Bergquist]

Are the phones using power bricks, or inline power?

Why are the switches plugged into the PC port on the phone?? That is meant for a host PC and not a connection to another switch.

If we have the IP phone plugged into a switch, then a host PC plugged into the PC port does the same problem occur?

[zcude]

All the phones use power bricks.

The majority of the phones have Dell PC's plugged into the PC port. We used the switches to see if it was just the Dell PC's that caused the phones to reboot or if it was the link itself. You can plug a switch into the PC port of the phone and plug computers into that switch and be able to reboot the pc's without the phone restarting, but as soon as you unplug and plug back in the PC port the phone will restart. Definitely something to do with that PC port link state.

[kthorngr]

I would be interested in looking at the ethereal trace. Let me know what you have connected to the phone and where you captured the trace from. You can email to me at kthorngr@cisco.com.

Kev

[christopherg]

This seems to be a re-occuring problem with phone loads. I've seen fixes for problems such as this in a few different bug reports.

Recently I upgraded one of my phones to 5.0(5). Shortly after I noticed that when the computer attached to the PC port rebooted the phone would reset at exactly the same time the OS started to load. I upgraded the phone to 5.0(6) and the problem was resolved.

I would try downgrading to a load that does not have this problem.