Why 2950 Port up and down

Unanswered Question
Jul 2nd, 2007

Hello there,

I am using a cisco 2950 for upgrading some CPEs. The CPE gets IP from a DHCP server connects to the same switch.

upgrade CPE takes about 2 minutes, then they will be unplugged from switch and new CPE will be plugged in. Then I found out some switch ports shutdown after a few times, though I have put no shutdown on all ports.

However those ports will work again if I cold restart the switch.

Here I attached the config. Could anybody please help me find out why?

I have this problem too.
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Edison Ortiz Mon, 07/02/2007 - 06:59

The ports may be going into err-disabled for some reason. You can verify why the ports go into err-disable by typing:

"sh int status err-disabled"

BTW, you don't have to restart the switch. All you need to do is, under the interface:


no shut.


annieliu_se Mon, 07/02/2007 - 07:31

If those ports are err-disabled, should not those LEDs shows orange? But these ports LED shows no indicators.

royalblues Mon, 07/02/2007 - 07:40

You can also configure error disable recovery which can recover the port automatically in 30 secs.

But if this the case you run into, you should be looking in your network to see why it happens rather than just ensuring the port is up


Edison Ortiz Mon, 07/02/2007 - 07:46

No, once in err-disabled, the port's LED will be off.

Orange can be an indication of errors on the port or STP-blocking mode. Again, depending on the switch.

annieliu_se Mon, 07/02/2007 - 07:50

I see. I will have to go on checking tomorrow. Now they shutdown the switch which is located at a warehouse. I will come back tomorrow. Thanks for help.

lifeisgreat Tue, 07/03/2007 - 01:30


It could be due to your ios is corrupted and causing the switchport up/down. It is recommended to get the ios upgraded. Hope it helps

annieliu_se Wed, 07/04/2007 - 00:59


I didn't find why it shutdown since when I sh int status errdisable, it shows nothing.How?ver I have solved the problem with set fix speed on those ports.

Thank you guys for help!

Edison Ortiz Wed, 07/04/2007 - 06:53

Then the problem was a speed/duplex mismatch issue. I don't recommend setting the speed and duplex on workstation ports, specially if you have roaming users connecting to those ports. This will create problems in the future, if other users have their NIC set to auto/auto while you have the switch set to 100/FD.

You should advise the users to set their NIC to auto/auto and you should the same at the switchport.


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