You can perform most of the basic interface troubleshooting using the show interfaces gigabitethernet , or show interfaces tengigabitethernet command and examining several areas of the output to determine how the interface is operating.
The following example shows an output of both the show interfaces gigabitethernet and show interfaces tengigabitethernet commands:
Router# show interfaces GigabitEthernet 3/0/0
GigabitEthernet3/0/0 is up, line protocol is up
Hardware is BUILT-IN-2T+20X1GE, address is badb.adbb.79c0 (bia badb.adbb.79c0)
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 not supported
Full Duplex, 1000Mbps, link type is auto, media type is SX
output flow-control is off, input flow-control is off
ARP type: ARPA, ARP Timeout 04:00:00
Last input 2d14h, output 2d06h, output hang never
Last clearing of "show interfaces" counters 2d06h
Input queue: 0/375/0/0 (size/max/drops/flushes); 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
70388928 packets input, 24628646826 bytes, 0 no buffer
Received 0 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
70399206 packets output, 24905239826 bytes, 0 underruns
0 output errors, 0 collisions, 3 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
Router# show interfaces TenGigabitEthernet 3/0/20
TenGigabitEthernet3/0/20 is up, line protocol is up
Hardware is BUILT-IN-2T+20X1GE, address is badb.adbb.79d4 (bia badb.adbb.79d4)
MTU 1500 bytes, BW 10000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive not supported
Full Duplex, 10000Mbps, link type is force-up, media type is 10GBase-LR
output flow-control is unsupported, input flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 2d14h, output 2d06h, output hang never
Last clearing of "show interfaces" counters 2d06h
Input queue: 0/375/0/0 (size/max/drops/flushes); 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
702060742 packets input, 245584812270 bytes, 0 no buffer
Received 0 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
702060725 packets output, 248397436760 bytes, 0 underruns
0 output errors, 0 collisions, 3 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
To verify that your interface is operating properly, complete the steps described in Table 3-1
:
Action
|
Example
|
From the global configuration mode, enter the show interfaces gigabitethernet or the show interfaces tengigabitethernet command.
|
Router# show interfaces gigabitethernet 2/0/1
Router# show interfaces tengigabitethernet 5/0/20
|
Verify that the interface is up.
|
Router# show interfaces gigabitethernet 2/0/1
GigabitEthernet2/0/1 is up
, line protocol is up
Router# show interfaces tengigabitethernet 2/0/21
TenGigabitEthernet2/0/21 is up,
line protocol is up (connected)
|
Verify that the line protocol is up.
|
Router# show interfaces gigabitethernet 2/0/1
GigabitEthernet2/0/1 is up, line protocol is up
Router# show interfaces tengigabitethernet 2/0/21
TenGigabitEthernet2/0/21 is up, line protocol is up (connected)
|
Observe the Cyclic Redundancy Check (CRC) counter.
|
0 input errors, 0 CRC, 0 frame, 130043940 overrun, 0 ignored
|
Observe the carrier signal counters.
|
0 lost carrier, 0 no carrier
, 0 pause output
0 output buffer failures, 0 output buffers swapped out
|
For more information about the verification steps and possible responses to correct the detected problems, see the following
sections: