show interface loopback
To display information about the loopback interface, use the show interface loopback command.
show interface loopback lo-number [ brief | description ]
Syntax Description
|
lo-number |
Loopback interface number. The range is from 0 to 1023. |
|
brief |
(Optional) Displays a brief summary of the loopback interface information. |
|
description |
(Optional) Displays the description provided for the loopback interface. |
Command Default
None
Command Modes
EXEC mode
Command History
|
Release |
Modification |
|---|---|
|
7.0(1)N1(1) |
This command was introduced. |
Examples
This example shows how to display the configuration information for a specific loopback interface:
switch# show interface loopback 10
loopback10 is up
Hardware: Loopback
MTU 1500 bytes, BW 8000000 Kbit, DLY 5000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation LOOPBACK
0 packets input 0 bytes
0 multicast frames 0 compressed
0 input errors 0 frame 0 overrun 0 fifo
0 packets output 0 bytes 0 underruns
0 output errors 0 collisions 0 fifo
switch#
|
Field |
Description |
|---|---|
|
Loopback is ... |
Indicates whether the interface hardware is currently active (whether carrier detect is present), is currently inactive (down), or has been taken down by an administrator (administratively down). |
|
Hardware |
Hardware is Loopback. |
|
MTU |
Maximum transmission unit (MTU) of the interface. |
|
BW |
Bandwidth (BW) of the interface in kilobits per second. |
|
DLY |
Delay (DLY) of the interface in microseconds. |
|
reliability |
Reliability of the interface as a fraction of 255 (255/255 is 100 percent reliability), calculated as an exponential average over 5 minutes. |
|
txload |
Load on the interface for transmitting packets as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over 5 minutes. |
|
rxload |
Load on the interface for receiving packets as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over 5 minutes. |
|
Encapsulation |
Encapsulation method assigned to interface. |
|
LOOPBACK |
Indicates whether loopback is set. |
|
packets input |
Total number of error-free packets received by the system. |
|
bytes |
Total number of bytes, including data and MAC encapsulation, in the error-free packets received by the system. |
|
multicast frames |
Total number of multicast frames enabled on the interface. |
|
compressed |
Total number of multicast frames compressed on the interface. |
|
input errors |
Sum of all errors that prevented the receipt of datagrams on the interface being examined. This may not balance with the sum of the enumerated output errors, because some datagrams may have more than one error and others may have errors that do not fall into any of the specifically tabulated categories. |
|
frame |
Number of packets received incorrectly having a CRC error and a noninteger number of octets. On a serial line, this is usually the result of noise or other transmission problems. |
|
overrun |
Number of times the serial 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. |
|
fifo |
Number of First In, First Out (FIFO) errors in the receive direction. |
|
packets output |
Total number of messages transmitted by the system. |
|
bytes |
Total number of bytes, including data and MAC encapsulation, transmitted by the system. |
|
underruns |
Number of times that the far-end transmitter has been running faster than the near-end router’s receiver can handle. This may never happen (be reported) on some interfaces. |
|
output errors |
Sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this may not balance with the sum of the enumerated output errors, as some datagrams may have more than one error, and others may have errors that do not fall into any of the specifically tabulated categories. |
|
collisions |
Loopback interface does not have collisions. |
|
fifo |
Number of First In, First Out (FIFO) errors in the transmit direction. |
This example shows how to display the brief information for a specific loopback interface:
switch# show interface loopback 10 brief
--------------------------------------------------------------------------------
Interface Status Description
--------------------------------------------------------------------------------
loopback10 up --
switch#
