Here’s an example output of the “show interface gi 1/0/0” command on a Cisco switch, along with an explanation of each stat:
GigabitEthernet1/0/0 is up, line protocol is up
Hardware is Gigabit Ethernet, address is 0011.2233.4455 (example MAC address)
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, media type is RJ45
output flow-control is unsupported, input flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:01, output hang never
Last clearing of “show interface” counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 1000 bits/sec, 2 packets/sec
5 minute output rate 2000 bits/sec, 4 packets/sec
1000 packets input, 100000 bytes, 0 no buffer
Received 1000 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 1000 multicast, 0 pause input
2000 packets output, 200000 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out
Explanation of each stat:
- Interface Status: GigabitEthernet1/0/0 is up and the line protocol is up, indicating the physical and logical connectivity status of the interface.
- Hardware: Specifies the type of interface hardware, in this case, Gigabit Ethernet.
- MAC Address: The MAC address assigned to the interface.
- MTU: Maximum Transmission Unit, the maximum packet size in bytes.
- BW: Bandwidth of the interface in kilobits per second.
- DLY: Transmission delay of the interface in microseconds.
- Reliability: Reliability rating of the interface.
- txload: Transmit load and rxload: Receive load on the interface, represented as a fraction of 255.
- Encapsulation: Encapsulation method used, in this case, ARPA (Ethernet).
- Loopback: Specifies if loopback is enabled or disabled.
- Keepalive: Keepalive timer interval.
- Duplex: Duplex mode of the interface, in this case, full-duplex.
- Speed: Speed of the interface, in this case, 1000 Mb/s.
- Media Type: Type of media connected to the interface, in this case, RJ45 (copper Ethernet).
- Flow Control: Indicates if flow control is supported on the interface (unsupported in this example).
- ARP: Address Resolution Protocol details, including ARP type and timeout.
- Last Input/Output: Time since the last input and output on the interface.
- Last Clearing: Time when the counters for the “show interface” command were last cleared.
- Input Queue: Current size of the input queue and its thresholds (drops/flushes).
- Total Output Drops: Number of packets dropped during transmission.
- Queueing Strategy: The queuing strategy used by the interface.
- Output Queue: Current size of the output queue and its maximum capacity.
- Input Rate: Average input rate in bits/sec and packets/sec over the last 5 minutes.
- Output Rate: Average output rate in bits/sec and packets/sec over the last 5 minutes.
- Input Packets/Bytes: Total number of packets and bytes received by the interface.
- Broadcasts/Runts/Giants/Throttles: Received broadcast packets, runt packets, giant packets, and throttled packets.
- Input Errors: Number of input errors, including CRC errors, frame errors, overrun errors, and ignored errors.
- Watchdog/Multicast/Pause Input: Watchdog timer status, number of multicast packets received, and pause input status.
- Output Packets/Bytes: Total number of packets and bytes transmitted by the interface.
- Output Errors/Collisions/Interface Resets: Number of output errors, collisions, and interface resets.
- Unknown Protocol Drops: Number of packets dropped due to unknown protocols.
- Babbles/Late Collision/Deferred: Babbled packets, late collisions, and deferred transmissions.
- Lost Carrier/No Carrier/Pause Output: Status of carrier signal, pause output, and number of lost carrier events.
- Output Buffer Failures/Swapped Out: Number of output buffer failures and output buffers swapped out.
Understanding the output of the “show interface” command allows network administrators to monitor interface performance, troubleshoot issues, and analyze traffic patterns on Cisco switches.