Hi every one, I hope every one if fine and enjoying good Health, for last couple of weeks a lot of people asked me if I can explain each and every line of output from Cisco one important command when we start troubleshooting any thing which is
Show interface Gi0/10
Output from the command above is explained each output one by one.
Show interface Gi0/10
Output from the command above is explained each output one by one.
GigabitEthernet0/10 is up,
Indicates whether the interface hardware is
currently active and if it has been taken down by an administrator.
"Disabled" indicates the router has received errors in a keep alive
interval and some time you have port security setup you will see error disbaled
line protocol is up (connected)
This indicates whether the software processes that
handle the line protocol believe the interface is usable (that is, whether
keepalives are successful)
Hardware is Gigabit Ethernet,
address is 0022.0d50.2d32 (bia 0022.0d50.2d32)
Hardware
type and Ethernet address.
MTU 1500 bytes, BW 1000000
Kbit, DLY 10 usec,
Maximum
Transmission Unit of the interface.
Bandwidth
of the interface in kilobits per second.
Delay
of the interface in microseconds.
reliability 255/255, txload
1/255, rxload 1/255
Reliability
of the interface 255/255 is 100% reliability , calculated
on average over 5 minutes.
Load on the interface 255/255 is completely saturated link it is also calculated on average over 5 minutes
Encapsulation ARPA, loopback
not set
Encapsulation method assigned to
interface.
Keepalive not set
Indicates
whether keepalives are set or not.
Full-duplex, 1000Mb/s, link
type is auto, media type is 1000BaseSX SFP
Duplex setting of the interface if the interface is full Duplex , in the example above I have media type of SFP fiber interface module
ARP type: ARPA, ARP Timeout
04:00:00
Type
of Address Resolution Protocol assigned.
Last input 00:00:00, output
00:00:03, output hang never
Number
of hours, minutes, and seconds since the last packet was successfully received
by an interface, it is Useful for knowing when an interface failed.
Number
of hours, minutes, and seconds since the last packet was successfully
transmitted by an interface
Number
of hours, minutes, and seconds since the interface was last reset
because of a transmission that took too long.
When the number of hours in any
of the "last" fields exceeds 24 hours, the number of days and hours is printed. If that field overflows,
asterisks are printed.
Last clearing of "show
interface" counters never
Time
at which the counters that measure cumulative statistics like number of
bytes transmitted and received
Input queue: 0/75/0/0
(size/max/drops/flushes); Total output drops: 0
Number
of packets in output and input queues. Each number is followed by a slash, the
maximum size of the queue, and the number of packets dropped due to a full
queue or saturation.
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 14000
bits/sec, 15 packets/sec
5 minute output rate 4000
bits/sec, 4 packets/sec
Mentions Hardware Queue which is First in First out everytime
Average
number of bits and packets transmitted per second in the last 5 minutes.
you can even guess the transmit speed of the interface as well from the 5 minutes output , if you dont have acces to NMS
71618919 packets input, 21731123446 bytes, 0
no buffer
Total
number of error-free packets received by the system
Number
of received packets discarded because there was no buffer space in the main
system
Received 57218887 broadcasts (26378769 multicasts)
Total
number of broadcast or multicast packets received by the interface.
0 runts, 0 giants, 0
throttles
This is quiet important this tells us Runts are the number
of packets that are discarded because they are smaller than the medium's
minimum packet size. i.e any Ethernet packet that is less than 64
bytes is considered a runt.
Number
of packets that are discarded because they exceed the medium's maximum packet
size. For example, any Ethernet packet that is greater than 1,518 bytes is
considered a giant.
0 input errors, 0 CRC, 0
frame, 0 overrun, 0 ignored
Cyclic
redundancy checksum generated by the originating LAN station or far-end device
does not match the checksum calculated from the data received.
On a LAN, this
usually indicates noise or transmission problems on the LAN interface or the
LAN bus itself. A high number of CRCs is usually the result of collisions or a
station transmitting bad data or Bad data cabling or any EMI.
Number
of times the receiver hardware was unable to hand received data to a hardware
buffer because the input rate exceeded the receiver's ability to handle the
data.#
Number
of received packets ignored by the interface because the interface hardware ran
low on internal buffers. These buffers are different than the system buffers
mentioned previously in the buffer description. Broadcast storms and bursts of
noise can cause the ignored count to be increased.
0 input packets with dribble
condition detected
Dribble
bit error indicates that a frame is slightly too long however router accepts this frame
9667499 packets output,
1711527019 bytes, 0 underruns
Number
of times that the transmitter has been running faster than the router can
handle. This may never be reported on some interfaces.
0 output errors, 0
collisions, 1 interface resets
Sum
of all errors that prevented the final transmission of datagrams out of the
interface being examined.
Number
of messages transmitted due to an Ethernet collision. This is usually the
result of an overextended LAN
A packet that collides is counted only once in output packets.
0 babbles, 0 late collision,
0 deferred
The
transmit jabber timer expired.
Number
of late collisions. Late collision happens when a collision occurs after
transmitting the preamble.
Deferred
indicates that the chip had to defer while ready to transmit a frame because
the carrier was asserted.
0 lost carrier, 0 no
carrier, 0 PAUSE output
Number
of times the carrier was lost during transmission.
Number
of times the carrier was not present during the transmission.
0 output buffer failures, 0
output buffers swapped out
Number
of failed buffers and number of buffers swapped out.
Source :- Cisco.com
