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Cisco 3750 Switchport Intermittent Green/Amber

Medium Priority
Last Modified: 2013-12-23
Hello, I have a (2) Cisco 3750's connected via trunked ports that traverse a radio shot between distant areas(the information is tunneled). We will lose connectivity to the far side portion of the network and I was given information that when this happens the trunked port will flash intermittent Green and Amber and we lose connectivity. Once the tech on the other end disconnects and reconnects the cable, the flashing will stop for awhile. Logs for the far end interface show only the manual disconnects.

My question is this: Is the intermittent flashing an indication that it has received some sort of bad input from the radio?

We are not seeing any problems with the network and work in a harsh environment, thus we think the radio equipment could be at fault, but have no way to be sure.

Thank you for any help!
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Istvan KalmarHead of IT Security Division
Top Expert 2010


It seems there is a duplex mismatch, did you set the ports?


Thanks for the suggestion, I just checked and the Duplex is set to full on both sides. Is what I think the problem is/was, was cabling. I ran a Cable-Diagnostics test and it showed some failures. They have replaced the cable and it has not dropped since.

Please keep any ideas coming!

Top Expert 2011

Check speeds also, is it a Gigabit switch? I would also suggest to check STP

This is normally an indication of errors on the link.

Have a look at

show interface g1/0/X

on the switchport connected to the radio to see if there are any input errors.
Hey guys, just closing this thread, Thanks for all your help. Yes, there were tons of input errors and we had the far-side guys replace the cable and its been good since. Thanks again everybody!

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