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Power outage and Cross Overs oh my!


We have lots of 2950's with IOS 12.1.12c.EA1.

At certain schools after a power outage the Cross-Over ports don't link up. They are all running the same configs and no errors are reported via "sh post".

If I unplug either side of the cross over and replug it still won't link (however in "sh int status" it says connected!)

I have to unplug the cross over and power off the switches then power on and reconnect the cross over. Then all is well.

Is this a hardware,IOS,config issue.

The Cross over ports are very simple:

switchport mode access (no vlans etc)




Re: Power outage and Cross Overs oh my!


Why do you need a cross over cable for ?? You need it only when you connect 2 switches. You need a straight through cable to connect your host PC to the switch. Are you connecting 2 switches together via cross-over cable ?

Do you see any changes in the config after the reboot ?

Well, do you see the booting sequence of the switch on the terminal program as that will tell us for hardware issue, if there is any ?

If all the tests are passed it points us towards what could be possibly be the software part.

What happens if you hardcore the speed and duplex on the ports. Try that... The last option that we can try is upgrading the software on the switch.


-amit singh

Re: Power outage and Cross Overs oh my!


in addition to amits post i would also suggest to check out whether any error disable option is enabled in your switch which can also be a potential reason for the same ,some flaps may disable ur ports which can come up once u reset them.

Also are you seeing anything to upgrade your ios from 12.1.12 train to 12.1.22 standard GD Version ?

is it possible to do that ? coz we do have switches connected all 24 ports back to back with cross cables with above mentioned ios without any issues for quite sometime now...


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