Unifi SFP+ RX Fault on only one switch?

[AB_IT]

Hi All,

 

So the main switch that our router plugs into is disconnecting all the time (or so it says in the Unifi 'events'). I've looked and both SFP+ ports that are aggregated to another switch show 'RX Fault'. I looked at the ports on the other switch and there's no error.

 

I thought it might have something to do with polarity of the cables but nothing has been changed and it's only just started reporting an RX fault in the last month or so (been running for 6-7 months with no issue since then)

 

I'm also confused as shouldn't both switches be reporting an RX fault? I'd also presume that if any switch would disconnect from the network it would be our second switch as that uplinks to this switch... if that makes sense?

 

Any help or advice would be appreciated.

 

First Switch (Connects directly to router)

 

Second switch (Connects via SFP+ to first switch)

 

[ZeroHour]

Which switch model and what firmware is on it?

Have you tried a reboot of the switch out of interest?

[AB_IT]

Which switch model and what firmware is on it?

Have you tried a reboot of the switch out of interest?

 

I just updated it to the latest version but to no avail, still doing the same thing. Even after a reboot.

 

Here's the details

 

[BlueFoxSystems]

Does the same error happen if you swap the SFP modules between the switches?

[Michael]

I've seen similar behaviour and narrowed it down to SFP+ auto-negotiation. Optionally you can force the mode in the controller, which normally works after a reboot.

[FN-GM]

I've seen similar behaviour and narrowed it down to SFP+ auto-negotiation. Optionally you can force the mode in the controller, which normally works after a reboot.

 

This is a likely cause. I have had issues on HP and Cisco with fibre auto negotiation. Interestingly both occasions it was using single mode fibre.

[AB_IT]

Thanks all! I'm going to give that a go!

[AB_IT]

Hey All,

 

It's still doing it even though I've changed the auto-negotiation on both switches. Maybe a cable problem?

 

It literally disconnects for 10 seconds, re-provisions and then is connected again. Sometimes this can be okay for as long as 3-4 hours sometimes there's 20 minutes between disconnects.