04-01-2009 06:15 AM - edited 03-06-2019 04:56 AM
I'm receiving the following display on a 2811 fast ethernet connection and am not sure what it means:
FastEthernet0/0 is up, line protocol is up
20 unknown protocol drops
04-01-2009 06:25 AM
I have researched this before and have never been able to get a definitive and authoritative answer, not even from Cisco TAC.
These oftentimes appear with absolutely no other indication that your network performance has been adversely effected.
If you cannot explain these errors, you can use a sniffer to indentify the unknown protocol.
HTH (It probably doesnt, but its the best I can do) :-)
Victor
04-01-2009 06:50 AM
Thanks, Victor!
04-01-2009 06:42 AM
What device is port F0/0 connected to?
Can you do a sniffer to see what packet is received when this count increments?
By the way, you can check your IOS version to see if you hit this bug CSCsx18388.
04-01-2009 06:55 AM
It's connected to a 2924-XL switch with
c2900xl-c3h2s-mz.120-5.WC15.bin.
Unfortunately, we don't have a sniffer.
I'm trying to use nGenius to identify the protocol. Fortunately it doesn't appear to be affecting performance...
04-01-2009 07:17 AM
Some times you can get dropped packets
when one device is trying to negotiate ISL or dot1q trunks and the other device does not understand the trunking protocol.
Can you ensure that both the switch and router have the ports set to not trunk
04-01-2009 07:42 AM
No trunking on either. Just vlan1...
04-01-2009 07:45 AM
Is the switchport set to portfast
04-01-2009 08:00 AM
Frederick,
Well, You're gonna love MIB. (grin)
#########
ifInUnknownProtos (.1.3.6.1.2.1.2.2.1.15)
: These are counted as unclassified errors.
The variables previously listed that do not say they appear in show interfaces are not available anywhere other than SNMP.
#########
Please don't hesitate to check out this link.
http://www.cisco.com/en/US/tech/tk648/tk362/technologies_q_and_a_item09186a00800b69ac.shtml#QQ1
HTH,
Toshi
04-01-2009 08:13 AM
and also
switchport mode access
You should also move your servers / hosts
off of VLAN 1 as this is not best practice
04-01-2009 08:14 AM
Hi Fred, how fast that counter increments? If you see it increase by one everytime you type "show interface", it might be related to the bug I mentioned before.
04-01-2009 08:30 AM
looks like about 4 per 10 seconds...!?!
04-01-2009 11:36 AM
Can you show us the output from a
show interface fa0/1 switchport
On the switchport that connect to the router
04-01-2009 11:53 AM
UMB208R0#sh int fa0/0
FastEthernet0/0 is up, line protocol is up
Hardware is MV96340 Ethernet, address is 0013.8084.ae18 (bia 0013.8084.ae18)
Description: LAN interface at 700 E Santa Fe St Olathe
Internet address is 10.110.81.1/24
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 05:58:49
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 2000 bits/sec, 3 packets/sec
5 minute output rate 2000 bits/sec, 2 packets/sec
108257 packets input, 22583077 bytes
Received 10522 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
94558 packets output, 38512505 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
6151 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
04-01-2009 01:14 PM
can you post the port configuration on 2900 switch and the output of "sh int fa x/y switchport"
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