Cisco2851 is rebooting constantly.

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Jul 29th, 2009
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I have a Cisco2851 with 2 VWIC2-2MFT-T1/E1, I'm using 3 E1 ports, but this device is rebooting constantly, so I lose data and voice service 1 or 2 minutes.

I reviewed power connections and they are Ok, I move to 3 different UPS and I got the same result.

Do you know If there are IOS commands where I can check If it has hardware problem or what else I can do?

Note: I changed the chassis 2851 5 hours ago and I got the same result.

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Collin Clark Wed, 07/29/2009 - 07:41
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Sounds more like an IOS bug. I would start by removing all the cards. If it's still rebooting try changing IOS. If that doesn't fix it, I would call TAC.

Hope that helps.

luisveraza Wed, 07/29/2009 - 07:44
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I have another router, same IOS, same hardware and it's working properly.

I'll remove the cards, one by one.

Thank you !.

Collin Clark Wed, 07/29/2009 - 07:57
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That's the crazy thing about bugs. Some routers are affected some are not.

paolo bevilacqua Wed, 07/29/2009 - 08:04
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That is normal, not every router sees same traffic and conditions.

You have to look at the crash message (if any) to understand what's going on.

luisveraza Wed, 07/29/2009 - 08:08
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Ok, do you know how I can see a crash message, any logs ?.

Collin Clark Wed, 07/29/2009 - 12:47
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It should be in flash. Try dir /all. I believe the crash dump starts with crashfile.... Also check what the power on in show version. Example-

System returned to ROM by s/w reset

Richard Burts Thu, 07/30/2009 - 04:44
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There might be some log messages that would help to identify the issue. You can not depend on log messages sent to an external syslog server because as it crashes the router may not be able to send all of its log messages. And after it crashes and reboots there is not anything in the logging buffer that is helpful. So I would suggest that it might be good to put some PC or terminal server connected to the console of the router and displaying all of the console messages (and be sure that the console logging severity level is set to debugging). This would allow you to see any log messages generated around the time of the crash.

Also show version will usually give information about the last time that the router restarted. In the case of a crash it will sometimes have a helpful pointer to the cause of the crash. So after the next crash you might want to take a careful look at show version.




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