The show interface command can be used with interface parameters, for example, show
interface serial 0. This provides information pertaining to just serial 0. By itself, the
show interface command provides information about all interfaces on the router.
The show interface command displays information regarding the encapsulation, layer 1 and
layer 2 status, and the LMI DLCI. In the following code, the show interface serial 0 command
is used. Notice the encapsulation is Frame Relay. The LMI information is shown as well.
Router#show interface serial0
Serial0 is up, line protocol is up
Hardware is HD64570
MTU 1500 bytes, BW 1544 Kbit,DLY 20000 usec,rely 255/255,load 1/255
Encapsulation FRAME-RELAY,loopback not set,keepalive set(10 sec)
LMI enq sent 0, LMI stat recvd 0, LMI upd recvd 0, DTE LMI down
LMI enq recvd 0, LMI stat sent 0, LMI upd sent 0
LMI DLCI 1023 LMI type is CISCO frame relay DTE
FR SVC disabled, LAPF state down
Broadcast queue 0/64, broadcasts sent/dropped 0/0, interface broadcasts 0
Last input never, output never, output hang never
Last clearing of "show interface" counters never
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
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 packets output, 0 bytes, 0 underruns
0 output errors, 0 collisions, 19 interface resets
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions
DCD=down DSR=down DTR=down RTS=down CTS=down
Router#
Notice that the LMI counter information is shown, as well as the LMI type, which is Cisco
by default. As you can see, this output shows both errors for the interface and the time that the
interface counters were last cleared.