Cisco Show Interface Command Explaination

Did you ever use this command? ofcouse every Cisco engineer will use this command to verify or trouble shooting. This is some important thing you should understand about show interface command.
let't try the command on cisco router :

R1#sh int g0/0
GigabitEthernet0/0 is up, line protocol is up (connected)
Hardware is CN Gigabit Ethernet, address is 000b.be79.d601 (bia 000b.be79.d601)
Internet address is
MTU 1500 bytes, BW 1000000 Kbit, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 100Mb/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 00:00:08, output 00:00:05, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0 (size/max/drops); Total output drops: 0
Queueing strategy: fifo
Output queue :0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
0 watchdog, 1017 multicast, 0 pause input
0 input packets with dribble condition detected
0 packets output, 0 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out

Let’s take a look at some of the output :
*No buffer If traffict full rest of traffict will stored in buffer if buffer full your packet will be discarded and will not be forwarded to destination. You can see how many packets are dropped with the ignored output.
*Ignored If the packet buffers are full, packets will be dropped. You see this increment along with the no buffer output. Typically if the no buffer and ignored outputs are incrementing, you have some sort of broadcast storm on your LAN. This can be caused by a bad NIC or even a bad network design.
*Runts Frames that did not meet the minimum frame size requirement of 64 bytes. Typically caused by collisions.
*Giants Frames received that are larger than 1518 bytes
*Input Errors This is the total of many counters: runts, giants, no buffer, CRC, frame, overrun, and ignored counts.This can point to cabling problems, hardware issues, or duplex mismatches.
*Output Errors Total number of packets (frames) that the switch port tried to transmit but for which some problem occurred.
*CRC At the end of each frame is a Frame Check Sequence (FCS) field that holds the answer to a cyclic redundancy check (CRC). If the receiving host’s answer to the CRC does not match the sending host’s answer, then a CRC error will occur.
*Frame This output increments when frames received are of an illegal format, or not complete, which is typically incremented when a collision occurs.
*Packets Output Total number of packets (frames) forwarded out to the interface.
*MTU (Maximal Transmition Unit) is max packet size allowed transmit trough this ethernet.
*BW is bandwidth of interfaces.

Update 14 08 2018 :
*Speed and duplex settings Good to know that the most common cause of interface errors is a mismatched duplex mode between two ends of an Ethernet link. This is why it’s so important to make sure that the switch and its hosts (PCs, router nterfaces, etc.) have the same speed setting. If not, they just won’t connect. And if they have mismatched duplex settings, you’ll receive a legion of errors, which cause nasty performance issues, intermittent connectivity—even total loss of communication!
*Input queue drops If the input queue drops counter increments, this signifies that more traffic is being delivered to the router that it can process. If this is consistently high, try to determine exactly when these counters are increasing and how the events relate to CPU usage. You’ll see the ignored and throttle counters increment as well.
*Output queue drops This counter indicates that packets were dropped due to interface congestion, leading to queuing delays. When this occurs, applications like VoIP will experience performance issues. If you observe this constantly incrementing, consider QoS.
*Late Collision If you have a duplex mismatch, a telling sign is that the late collision counter will increment.