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Switches port flapping in cold

Posted: Wed Jan 30, 2019 10:57 am
by Wifimax
-30 temp here currently and I have two switches that are flapping the LAN ports now that its cold out. Nothing is getting power cycled, the ports just go from 1gbps to 100mbps to down.

WS-12-250AC
firmware 1.4.5
~120watt draw
26C board temp

WS-24-400A
firmware 1.4.7rc14

~150watt draw

Both switches are powering Prism AP's and an AF5X.


I realize this is old firmware. A GUI reboot has actually resolved the issue for the past 5 minutes for me at the DC site. The AC site is still port flapping. Any ideas?

Re: Switches port flapping in cold

Posted: Wed Jan 30, 2019 11:03 am
by Wifimax
I have powered off 4 of the 12 sectors on the 24port and things appears to have stabilized for now.

Re: Switches port flapping in cold

Posted: Wed Jan 30, 2019 11:17 am
by wmtel
We are having the same issue here (temp is -22F right now). I am going to try powering down ports and see if that helps. Thanks!

Re: Switches port flapping in cold

Posted: Wed Jan 30, 2019 11:18 am
by sirhc
My guess is this is more of temperature contraction of parts like EThernet connectors.

Several times a year we have to dispatch tower guys to simply unplug and replug Ethernet connector. Normally happens in extreme temp ranges cold or hot.

viewtopic.php?f=14&t=4933#p28000

Re: Switches port flapping in cold

Posted: Wed Jan 30, 2019 12:19 pm
by Wifimax
Interesting.... But shutting off POE to a few of the ports to reduce power draw resolves the issue for us. Just very odd....

Re: Switches port flapping in cold

Posted: Wed Jan 30, 2019 12:30 pm
by sirhc
Wifimax wrote:Interesting.... But shutting off POE to a few of the ports to reduce power draw resolves the issue for us. Just very odd....


Then read this post: viewtopic.php?f=17&t=3934#p24989

And this thread: viewtopic.php?f=17&t=4930#p27991