Cisco Systems 17053 appendix Duplex, Mismatch, Correct, Manual, Configuration2

100 Mbps,		100 Mbps,	100 Mbps,	Duplex
Full−duplex		Full−duplex	Half−duplex	Mismatch 1
AUTO	100 Mbps,	100 Mbps,	100 Mbps,	Duplex
	Full−duplex	Half−duplex	Full−duplex	Mismatch 1
100 Mbps,				Correct
Full−duplex	100 Mbps,	100 Mbps,	100 Mbps,
				Manual
	Full−duplex	Full−duplex	Full−duplex
				Configuration2
				Link is
				established, but
				switch does not
100 Mbps,				see any
				autonegotiation
Half−duplex		100 Mbps,	100 Mbps,
	AUTO			information
		Half−duplex	Half−duplex
				from NIC and
				defaults to
				half−duplex
				when operating
				at 10/100 Mbps.
				Link is
				established, but
10 Mbps,				switch does not
Half−duplex	AUTO	10 Mbps,	10 Mbps,	see Fast Link
		Half−duplex	Half−duplex	Pulse (FLP) and
				defaults to 10
				Mbps
				half−duplex.
10 Mbps,				Neither side
Half−duplex	100 Mbps,	No Link	No Link	establishes link,
	Half−duplex			due to speed
				mismatch.
				Link is
				established, but
				NIC does not
AUTO	100 Mbps,	100 Mbps,	100 Mbps,	see any
				autonegotiation
	Half−duplex	Half−duplex	Half−duplex
				information and
				defaults to 100
				Mbps,
				half−duplex.
				Link is
				established, but
AUTO	10 Mbps,	10 Mbps,	10 Mbps,	NIC does not
				see FLP and
	Half−duplex	Half−duplex	Half−duplex
				defaults to 10
				Mbps,
				half−duplex.

1A duplex mismatch can result in performance issues, intermittent connectivity, and loss of communication. When you troubleshoot NIC issues, verify that the NIC and switch use a valid configuration.