UDLD Alert and switch port going down

[crizjohn]

port: 51, state: unidirectional (outbound fault), port_blocked: false  « hideneighbor_idF89E281D68C9neighbor_port52

one of the meraki switch showing this error and the port going down for a couple of min, it happening 5,6 times a day and all the switches connected from the same is also going down. any explanations.

[alemabrahao]

Hi,

This could be due to a variety of reasons, including high CPU usage on the switch, mismatched VLANs on trunk ports, or physical issues with the cables or switch port.

[crizjohn]

I've replaced the sfp's and fiber in both sides of the switch hoping to clear the issue, about the Vlan both runk ports are in Vlan 1 with limited number of users. 

port: 51, state: unidirectional (outbound fault), port_blocked: false  « hide

neighbor_id	F89E281D68C9
neighbor_port	52

the reference showing in the event log during the outage is the source switch port in the same switch, ring any bells ? 

[alemabrahao]

I suggest you read this documentation to understand a little better, if it's not clear I suggest you open a support case.

https://documentation.meraki.com/MS/Other_Topics/Unidirectional_Link_Detection_(UDLD)

[PhilipDAth]

This is usually a fibre or SFP fault.

When you say you replaced the fibre, do you mean just the patch leads?

Are all the fibres matching?  For example, all OS2 or all OM3?  Mixing and matching single and multi-mode fibre can lead to problems.  For example, using OM3 patch leads with an OM2 fibre run.

Are you using Meraki SFPs, or third-party?

Is everything operating in a room-temperature environment, or is some of it subject to extreme heat or cold?

Failing that, are the switches all running a current stable or better firmware version?