Hi! I'm getting this error on an access switch.
%CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on FastEthernet0/9 (not half duplex), with SEP00141C8Dxxxx Port 1 (half duplex).
Why is the phone port 1 half duplex? Shouldn't the phones be configured as auto-negotiation as default?
Could it be a cabling issue?
Will it affect the throughput / performance on that port?
This is happening with some of my other phones + switches.