Check Duplex Speed of Serial Link with Cisco Command

Explanation

The correct answer to the question is B. show interface.

The command "show interface" is used to display the current status and configuration of the interfaces on a Cisco device. This command can be used to determine the duplex and speed settings for a serial link.

To check the duplex and speed of a serial link using the "show interface" command, follow these steps:

1. Log in to the Cisco device.
2. Enter privileged EXEC mode by typing "enable".
3. Enter global configuration mode by typing "configure terminal".
4. Enter interface configuration mode for the serial interface by typing "interface serial interface_number" (where "interface_number" is the number of the serial interface you want to check, such as "interface serial 0/0/0").
5. Check the duplex setting by looking for the "Duplex" line in the output. It will show either "Full" or "Half".
6. Check the speed setting by looking for the "Speed" line in the output. It will show the speed in bits per second (bps).

For example, if you want to check the duplex and speed settings for serial interface 0/0/0 on a Cisco router, you would use the following commands:

kotlinCopy code
enable configure terminal interface serial 0/0/0 show interface 

The output will include information about the interface, including the duplex and speed settings.