Output Discards

[r0ssc0]

Logic monitor is showing output discards on meraki ports, does anybody know why an under utilised 1G port is getting output discards

[robk]

We're also seeing this on our me-225 - any clues welcome 

[Technomancer]

So I know this topic is a couple of years old, but I too am running LogicMonitor and seeing some huge "OutDiscardPercet" errors on my Meraki devices.  It used to happen occasionally, but starting yesterday (7/31/2024) it's been like non-stop.  Did you ever figure out if it was something legit or just some miscommunication between Meraki and LogicMonitor?

[Technomancer]

Anyone have any insight to offer?

[GIdenJoe]

Do you have this issue on all ports?
You could easily check if Meraki is actually reporting this by just capturing the snmp packets and see if it is actually reporting that.

It might be a reporting bug of the Meraki switch.  Maybe test if a reboot fixes it and if so do a bug report.

[Technomancer]

Actually, Meraki support came back to me with a reason.  This is due to IPV6 multicast traffic that get dropped by the switch ports from different VLANSs which is incrementing the interface outdiscard number , that is being reported over the SNMP.  We don't use IPv6 so IMHO the answer is we put in a GPO to disable IPv6 on PC NICs but boss doesn't think it's a good idea.  So I just turned off monitoring for OutDiscardPercent on Meraki devices.  

[GIdenJoe]

I didn't know they also count the protocol based discards.  They should normally only count discards due to buffer full issues.  This makes it harder to troubleshoot.

[Technomancer]

I agree.  Essentially I'm blind now if there is an actual problem.  Boss said that he's open to the idea of a GPO to turn off IPv6 but it's a "we'll get to it when we get to it" priority which means likely never.