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7206VXR System Freeze- No symptoms or crash info

We have a 7206VXR with an NSE-1. We have recently been suffering system hangs where physical interfaces are active but all L2/L3 forwarding has ceased. No console or telnet is possible. We have swapped the NSE card several times through maintenance and memory, reseated modules but we are still suffering this problem. As there is no crash, there is no crash info, so only a cold boot is possible and the system returns to normal status until the next freeze. The time in between system failures is sparodic and our monitoring tool does not indictae DoS attacks. Our secondary 7206VXR with the same hardware and IOS does not yet suffer this problem.


Re: 7206VXR System Freeze- No symptoms or crash info

I think new image or released is loaded configuring "encapsulation lapb dte multi" on serial port, causes the router get freezed. This happens after configuring "encapsulation lapb dce multi" on the connected router.

Also I think you have to follow few steps:

1. Verify cable connectivity.

2. Verify that the power supply is on and running.

3. Verify the router LED status. If all LEDs are down, it is most likely an issue with the power

supply of the router.

4. Was there a trigger?


Re: 7206VXR System Freeze- No symptoms or crash info

I agree that you need to find the trigger. But if there is no console communication, that's very bad.

- Have you recently upgraded IOS?

- Does Console port work normally, when the system is operational?

I could be some massive controller failure, or backplane failure. Maybe there is message outputted to the console just before it freezes. Try connecting it's console port to nearby router's AUX, and telneting to nearby router's IP with port number 2001 - so you can be connected to the console from far away. Also setup the console, aux and VTY timeouts to "0 0" so it never times out.

Make sure there is logging console and logging buffered debugging.

I bet it will output to console something before it freezes.