Autonegotiation of link speed and duplex mode for 10/100/1000BASE-T is possible through the functions standardized in IEEE 802.3u and 802.3ab. The two endpoints of a connection exchange capability information and choose the highest common speed and duplex supported by both.
Ethernet ports are referenced by module and port numbers (mod/port) on COS switches and by interface type and number (interface and one of ethernet, fastethernet, gigabitethernet, or tengigabitethernet) on IOS switches.
If certain problems are detected on a port, the switch automatically moves that port into the errDisable or “error disabled” state. This minimizes the effect that the problem port could have on the rest of the network.
Ports in errDisable can be ...