Refer to the following sample output:

Which Cisco Internetwork Operating System (IOS) command produces this output?

A.
show interfaces

B.
show interfaces summary

C.
show interfaces serial fast-ethernet

D.
show interfaces fast-ethernet 0/0

Explanation:
The show interfaces summary command will produce the given output. This command provides a summarized
view of all interfaces configured on a device.
The show interfaces command is incorrect because this command does not produce the displayed output. This
command is used to view information regarding statistics for specific interfaces. Without specifying an interface,a section for each interface will display, as in the example below for FastEthernet0:

The show interfaces serial fast-ethernet command is incorrect because this is not a valid Cisco IOS command.
The show interfaces fast-ethernet 0/0 command is incorrect. Although it produces similar output, that output
only relates to the FastEthernet 0/0 interface. An example of this output follows:

Notice that the line of output that says FastEthernet0 is up, line protocol is up indicates that Layers 1 to 3 of the
OSI Model are functioning correctly. Also, in the lower portion, there are no values in the error counters such as
input errors, output errors, and so on. Finally, make note in line 8 where the interface is set to autosense both
the duplex and the speed. Duplex and speed must be in agreement between the NIC on the host and the
switch port.
Objective:
Routing Fundamentals
Sub-Objective:
Troubleshoot basic Layer 3 end-to-end connectivity issues

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