SG350X SFP+ Port Duplex mismatch

[rand__]

Hi,

I have a SG350X which is connected to a Mellanox 6036 in Ethernet mode via a 4:1 splitting cable.

The Port on the Cisco is complaining about a Duplex mismatch every 5 minutes.

Since this is a 10G Port, no manual duplex configuration can be performed.

The Mellanox setup is correct, it has been in place since before the Cisco was brought in.

I am investigating a strange (temporarily occurring) STP issue that recently began, thats why I noticed this  issue in the first place.

Any idea why that would be/how to resolve it?

Thanks

[rand__]

So nobody never had that issue, heard of it, solved it?

[rand__]

Still getting

"DUPLEX_MISMATCH - Duplex mismatch detected on interface te1/0/3." every 5 minutes :/

[rand__ · Accepted solution]

Ok,

after ignoring this for a couple of month i looked at it again.

I found this: https://community.cisco.com/t5/routing/cdp-sw1-4-duplex-mismatch/td-p/3021049

So i disabled CDP as suggested and the problem is gone...