Contact at Ubiquiti Networks?

Gary Godard gary at
Wed May 27 13:51:25 UTC 2020

I have this exact same issue with Ubiquiti. Would go to network in which we
designed spanning tree Loops in the event of a switch failure the network
could automatically recover in keep portions from being disconnected. This
all works fine until power loss greater than the run time on the UPS's.
 Seems to me like a simple fix, simply do not activate the switch ports
until spanning tree is running and then activate them one at a time.


Gary Godard
Chief Technical Officer
308 Pine St
West Monroe, LA 71291
Office: 800-536-7035, Ext. 5201

Fax...: 888-471-8778
Direct: 318-884-9422
Email: gary at                  Web:


On Wed, May 27, 2020, 02:53 Phil Lavin <phil.lavin at> wrote:

> > Where did you find this?
> Found out the hard way after buying and installing 20 of them. When a
> single node in a VC reboots, it starts switching traffic some seconds
> before it does STP so any loops that were previously blocked now flood -
> usually overloading the other 3400s on the network. Apparently this is just
> how the Broadcom chip works and cannot be fixed. That, twinned with some
> other significant stability issues, caused them to all go back for a
> refund. They did say a PR would be raised for this though I don't believe
> it has been - I can't find an external one, anyway.
> The QFX51XX issue is currently a won't fix. Worked fine in 17.x, broke in
> 18.x. No documentation or reasoning for the change, other than giving the
> distinct impression that we don't spend enough for them to care.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the NANOG mailing list