You receive aMarvis Actionthat reports“Port negotiation mismatch detected on EX3400-48P.

Aport negotiation mismatchoccurs when the local and remote interfaces fail to agree on common speed or duplex settings.

Marvis Wired Assurance automatically detects this by analyzing telemetry from the switch’s physical interfaces.

You can resolve this by ensuringauto-negotiationis enabled on both ends (A) and verifying the peer device supports the802.3 autonegotiation standard(D).

Manually forcing half-duplex or replacing hardware is unnecessary unless the hardware is faulty.

“Marvis Wired Actions correlate interface negotiation errors with LLDP neighbor data to pinpoint mismatched configurations, helping administrators quickly verify speed/duplex compatibility and 802.3 autonegotiation support.”