Cisco CCNA (200-301)Network FundamentalsMedium
A network administrator is reviewing the output of the 'show ip interface brief' command on a Cisco router. One interface shows a status of 'administratively down, line protocol is down'. What does this status indicate?
- AThe interface has been manually disabled by an administrator.
- BThe interface is experiencing a physical layer issue, such as a disconnected cable.
- CThe interface is configured for an incorrect duplex setting.
- DThere is an IP address conflict on the network segment connected to this interface.
Show answer & explanationAnswer & explanation
Correct answer: A. The interface has been manually disabled by an administrator.
The 'administratively down' status specifically indicates that the interface has been manually disabled using the 'shutdown' command in interface configuration mode. The 'line protocol is down' part is a direct consequence of the administrative shutdown.
Why the other options are wrong
- B. A physical layer issue would typically show 'down, down' (interface down, line protocol down) without the 'administratively' prefix.
- C. Incorrect duplex settings can cause performance issues and errors, but not an 'administratively down' status.
- D. An IP address conflict would not typically result in an 'administratively down' status; it would more likely cause intermittent connectivity or error messages.
Cisco IOS Interface Status
Cisco IOS interface status codes provide quick insight into the operational state of a network interface, indicating physical and logical connectivity.
- 'Up, Up': Interface is active and functional.
- 'Down, Down': Physical or data link layer issue (e.g., cable, no signal).
- 'Administratively Down, Down': Interface manually disabled via 'shutdown' command.
Memory trick: Traffic light for interfaces: Red means admin stopped it, Yellow means a physical problem, Green means go.