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In order to check to see how long the port is in Up or Down status, use the show interfaces [interface id] command.

In the example, under the show interfaces FastEthernet0/1 command, look at a line that shows something such as: Last input 00:00:41, output 00:00:00, output hang never. This shows the last time a port sent or received traffic. Likewise, the Last input never, output never, output hang never status means the port is not in use.

This is an example of output from the show interfaces command for an interface:

Switch#show interfaces FastEthernet0/1
FastEthernet0/1 is up, line protocol is up
  Hardware is Fast Ethernet, address is xx.xx.xx.xx
  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
  reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not set
  Auto-duplex (Full), Auto Speed (100), 100BaseTX/FX
  ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:41, output 00:00:00, output hang never
!--- This line shows the uptime or downtime status.
  Last clearing of "show interface" counters never
  Queueing strategy: fifo
  Output queue 0/40, 0 drops; input queue 0/75, 0 drops
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 1000 bits/sec, 1 packets/sec
  103876 packets input, 62915296 bytes
  Received 103875 broadcasts, 0 runts, 0 giants, 0 throttles
  0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
  0 watchdog, 6831 multicast
  0 input packets with dribble condition detected
  610233 packets output, 83504453 bytes, 0 underruns
  0 output errors, 0 collisions, 1 interface resets
  0 babbles, 0 late collision, 0 deferred
  0 lost carrier, 0 no carrier

"How long the port is in Up or Down status" is NOT the same thing as "the last time a port sent or received traffic." This article purportedly explains how to find the former, but actually explains how to find the latter. In the given example, how long has the port been up? Impossible to tell.

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