Interface reset....

[jimmysands73_2]

Question a few days ago, I did a small lab this morning.

When I unplugged the ethernet link (2950 into a mini switch) the interface reset counter did not increment.

When I turned power off for about 10 seconds, then back up to the mini sw, the reset counter did not increment.

When I admin shut the int for the enet connection on the 2950, it did increment by one.

When I no sh the int, it did increment by one.

And when I reboot the switch all counters were reset...I saw this

Switch>en

Switch#sh int | inc reset

     0 output errors, 2 interface resets

     0 output errors, 0 collisions, 2 interface resets

     0 output errors, 0 collisions, 2 interface resets

......

     0 output errors, 0 collisions, 2 interface resets

I always thought the counter was incremented when a PC turned on / off or a device on the other end was turned on or off or cable unplugged or a flapping link, the only time I could get the counter to increment was when I admin shut the port.  This by no means is a complete test....but what I have found.  Has anyone found anything different?

[Rolf Fischer]

From "Troubleshooting Ethernet":

"Gives the number of times that an interface has been completely reset. This can happen if packets queued for transmission were not sent within several seconds. On a serial line, this can be caused by a malfunctioning modem that is not supplying the transmit clock signal, or by a cable problem. If the system notices that the carrier detect line of a serial interface is up, but the line protocol is down, it periodically resets the interface in an effort to restart it. Interface resets can also occur when an interface is looped back or shut down."

http://www.cisco.com/en/US/docs/internetworking/troubleshooting/guide/tr1904.html

HTH

Rolf