topic Re: unknown protocol drops on Ehternet Interface in Switching

unknown protocol drops on Ehternet Interface

ranjit123 — Wed, 06 Mar 2019 18:21:30 GMT

Dear Experts,

We are getting protocol drops on our Ehternet Interface of our core router, every time we run the commant show interface gig 0/1 the counters keep on increasing, kindly update what could be reason for the same.

Please find the Details as below

======================================================================================

RTR1#sh int gigabitEthernet 0/2

GigabitEthernet0/2 is up, line protocol is up

MTU 1500 bytes, BW 92160 Kbit/sec, DLY 100 usec,

reliability 255/255, txload 100/255, rxload 11/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 100Mb/s, media type is RJ45

output flow-control is XON, input flow-control is unsupported

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 00:50:55

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 8301

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 4207000 bits/sec, 4065 packets/sec

5 minute output rate 36188000 bits/sec, 8224 packets/sec

12811303 packets input, 1534544971 bytes, 0 no buffer

Received 54 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 5 multicast, 0 pause input

0 input packets with dribble condition detected

26044169 packets output, 3290592132 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

10 unknown protocol drops

414 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

=========================================================================================

Re: unknown protocol drops on Ehternet Interface

Giuseppe Larosa — Mon, 29 Mar 2010 12:25:21 GMT

Hello Ranjit,

if count increments by one at each execution of show command this should be a specific SW bug.

What device is this, and what IOS image is running on it?

otherwise there are possible reasons for this kind of counter:

receiving STP BPDUs or other L2 signalling protocol from connected switch port

or ISIS hello messages when ISIS is not enabled on router interface

for example we use ISIS and access layer switches complain of these unknown protocol drops because they don't use ISIS

given the very low count in comparison to total traffic this is not something to worry about

Hope to help

Giuseppe

Re: unknown protocol drops on Ehternet Interface

ranjit123 — Mon, 29 Mar 2010 12:27:05 GMT

its a 7206 Box with the below IOS Image

System image file is "disk2:c7200p-advsecurityk9-mz.124-15.T8.BIN"

Cisco 7206VXR (NPE-G2) processor (revision A) with 917504K/65536K bytes of memory.

Re: unknown protocol drops on Ehternet Interface

Giuseppe Larosa — Mon, 29 Mar 2010 12:29:29 GMT

Hello Ranjit,

this is fine info

but have you noticed if the counter increments by one each time you issue sh interface gi0/2?

Hope to help

Giuseppe

Re: unknown protocol drops on Ehternet Interface

ranjit123 — Mon, 29 Mar 2010 12:33:23 GMT

It increases every time, pls check the below output

=====================================================================

RTR1#$aces gigabitEthernet 0/2 | i unknown protocol drops
     71 unknown protocol drops
     475 unknown protocol drops
RTR1#$aces gigabitEthernet 0/2 | i unknown protocol drops
     72 unknown protocol drops
     476 unknown protocol drops
RTR1#$aces gigabitEthernet 0/2 | i unknown protocol drops
     73 unknown protocol drops
     477 unknown protocol drops
RTR1#$aces gigabitEthernet 0/2 | i unknown protocol drops
     74 unknown protocol drops
     478 unknown protocol drops
RTR1#$aces gigabitEthernet 0/2 | i unknown protocol drops
     75 unknown protocol drops
     479 unknown protocol drops
SRTR1#$aces gigabitEthernet 0/2 | i unknown protocol drops
     76 unknown protocol drops
     480 unknown protocol drops
RTR1#$aces gigabitEthernet 0/2 | i unknown protocol drops
     77 unknown protocol drops
     481 unknown protocol drops

=======================================================================

Re: unknown protocol drops on Ehternet Interface

Giuseppe Larosa — Mon, 29 Mar 2010 12:39:09 GMT

Hello Ranjit,

as you see you are generating these unknown protocol drops by yourself !!!

to get rid of this you should upgrade to a later IOS image

sh ver | inc image
System image file is "disk2:c7200p-advsecurityk9-mz.124-20.T.bin"

sh int gi0/2 | inc unknown
     0 unknown protocol drops
router#sh int gi0/2 | inc unknown
     0 unknown protocol drops
router#sh int gi0/2 | inc unknown
     0 unknown protocol drops

my box looks like free of this small issue

but I would wait to have other reasons to perform an upgrade

Hope to help

Giuseppe

Re: unknown protocol drops on Ehternet Interface

Ganesh Hariharan — Mon, 29 Mar 2010 12:42:58 GMT

Hi
It increases every time, pls check the below output
=====================================================================
RTR1#$aces gigabitEthernet 0/2 | i  unknown protocol drops
     71 unknown protocol drops
     475 unknown protocol drops
RTR1#$aces gigabitEthernet 0/2 | i  unknown protocol drops
     72 unknown protocol drops
     476 unknown protocol drops
RTR1#$aces gigabitEthernet 0/2 | i  unknown protocol drops
     73 unknown protocol drops
     477 unknown protocol drops
RTR1#$aces gigabitEthernet 0/2 | i  unknown protocol drops
     74 unknown protocol drops
     478 unknown protocol drops
RTR1#$aces gigabitEthernet 0/2 | i  unknown protocol drops
     75 unknown protocol drops
     479 unknown protocol drops
SRTR1#$aces gigabitEthernet 0/2 | i  unknown protocol drops
     76 unknown protocol drops
     480 unknown protocol drops
RTR1#$aces gigabitEthernet 0/2 | i  unknown protocol drops
     77 unknown protocol drops
     481 unknown protocol drops
=======================================================================

Hi Ranjit,

It is a bug in your ios Cisco Bug CSCsx18388which was first found in the below version

12.5TPI1
12.4(15)T8
12.4(23.4)T
12.4(23.7)T
12.4(24)T1

and then which are fixed in the following version

12.4(18e)M
12.4(23.15.6)PIC1
12.4(15)T9
15.0(1)M
12.4(24)T1
12.4(24)YG
12.4(24)GC1
12.4(24)MD
15.1(0.2)PI12a
15.1(0.10)T
12.4(24)YE

for more information about your problem just check out the below message related to bug details

CSCsx18388 Bug Details

"Unknown protocol drops" counter is incremented by one at each sh int
Symptom: "Unknown protocol drops" counter is incremented by one at each "show interfaces" command execution Conditions: "unknown protocol drops" counter getting incremented for "down" interface's also Workaround: No work around available

Remember to rate the helpful post

Ganesh.H

Re: unknown protocol drops on Ehternet Interface

ranjit123 — Mon, 29 Mar 2010 12:55:26 GMT

Dear All,

No Work around for the same???

Also in the IOS suggested any criticals bugs in the same??

Thanks,

Ranjit

Re: unknown protocol drops on Ehternet Interface

radiomen — Tue, 30 Nov 2010 06:33:14 GMT

I know this is an old conversation but the most likely cause of your issue is cdp. Enable cdp on your interface or disable cdp on your next connected device.

Re: unknown protocol drops on Ehternet Interface

madhu.kumar_2 — Tue, 30 Nov 2010 12:01:16 GMT

Unknown protocol drops reports the packets with unknown or un-configured protocol on a per interface basis. Therefore it can be any protocol that the router doesn’t recognize.

it means if you have disbaled CDP on teh router interface and enabled on other end , when both starts to speak over the CDP packets you router dont get recognised

it was cisco BUG with ID-CSCsx18388

go through the below link - a IOS upgrade will fix your problem

http://tools.cisco.com/Support/BugToolKit/search/getBugDetails.do?method=fetchBugDetails&bugId=CSCsx18388 (neec CCO login)

unknown protocol drops on Ehternet Interface

andrewjduffy — Wed, 02 May 2012 15:58:49 GMT

Hi - looks like you listed 12.4(24)T1 in the bug and fixed lists.

No worries. I can search the bug info to confirm the fixed ver of 12.4(24)Tx.