200-301: Cisco Certified Network AssociateDemo

An interface in down/down state indicates no active physical link. Error-disabled (D) occurs when the switch disables a port due to violations or security issues, resulting in down/down status. Speed mismatch (E) can also cause down/down if the interface cannot negotiate a compatible speed. By contrast, an administratively shut interface displays 'administratively down', duplex mismatch typically leaves the link up but unstable, and protocol mismatch usually shows up/down.