What layer of the OSI model would you assume the problem is in if you type show interface serial 1 and receive the following message? "Serial1 is down, line protocol is down."

A. Physical layer

B. Data Link layer

C. Network layer

D. None. It is a router problem.

Answer: Option A

Solution(By Examveda Team)

If you see that a serial interface and the protocol are both down, then you have a Physical layer problem. If you see serial1 is up, line protocol is down, then you are not receiving (Data Link) keepalives from the remote end.

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Related Questions on IOS and Security Device Manager

You type show running-config and get this output:

What do the two numbers following the exec-timeout command mean?

A. If no command has been typed in 35 seconds, the console connection will be closed.

B. If no router activity has been detected in 1 hour and 35 minutes, the console will be locked out.

C. If no commands have been typed in 1 minute and 35 seconds, the console connection will be closed.

D. If you're connected to the router by a Telnet connection, input must be detected within 1 minute and 35 seconds or the connection will be closed.