This may seem like a simple question, but I am having a hard time finding anything that clearly describes the meaning of "unknown protocol drops" when viewing interface stats. See the example below (towards the bottom) that was taken from an 1841 router running 12.4T.
FastEthernet0/0 is up, line protocol is up
Hardware is Gt96k FE, address is xxxxxxxxxxx
Description: xxxxxxxxxxxxxxxxxxxxx
Internet address is xxxxxxxxxxxxxxxxxxxxxx
MTU 1500 bytes, BW 100000 Kbit/sec, 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, 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 5d03h
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 3000 bits/sec, 6 packets/sec
5 minute output rate 5000 bits/sec, 9 packets/sec
12106574 packets input, 1221718176 bytes
Received 992153 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog
0 input packets with dribble condition detected
16927799 packets output, 2319562095 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
=> 45936 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
Anyone have an idea? What causes this? Thanks for any insights.
