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Output drops when the interface has no traffic

chemudupaty
Level 1
Level 1

on a 9500 Catos switch i have an interface up but i don't have any traffic on it. I see output drops increasing, does anyone know what these drops could be?

 

TenGigabitEthernet1/0/5 is up, line protocol is up (connected)
Hardware is Ten Gigabit Ethernet, address is c4b3.6a0a.a0e4 (bia c4b3.6a0a.a0e4)
Description: 
Internet address is x.x,x,x/30
MTU 9000 bytes, BW 10000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive not set
Full-duplex, 10Gb/s, link type is auto, media type is SFP-10GBase-SR
input flow-control is on, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:31, output hang never
Last clearing of "show interface" counters 08:19:45
Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 703652
Queueing strategy: fifo
Output queue: 0/40 (size/max)
30 second input rate 0 bits/sec, 0 packets/sec
30 second output rate 0 bits/sec, 0 packets/sec
4725 packets input, 1116876 bytes, 0 no buffer
Received 4725 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 4715 multicast, 0 pause input
0 input packets with dribble condition detected
0 packets output, 0 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
1004 unknown protocol drops

 

 

8 Replies 8

marce1000
VIP
VIP

 

 - FYI : https://www.cisco.com/c/en/us/support/docs/switches/catalyst-9300-switch/216236-troubleshoot-output-drops-on-catalyst-90.html

 M.



-- Each morning when I wake up and look into the mirror I always say ' Why am I so brilliant ? '
    When the mirror will then always repond to me with ' The only thing that exceeds your brilliance is your beauty! '

but there is literally no traffic on this interface, am i missing anything here?

 

  - In such cases it is always useful to use the latest  advisory release for the particular platform , in case of bugs :
                  https://software.cisco.com/download/home/286315863/type/282046477/release/Cupertino-17.9.3
   Check if this can help.

 M.



-- Each morning when I wake up and look into the mirror I always say ' Why am I so brilliant ? '
    When the mirror will then always repond to me with ' The only thing that exceeds your brilliance is your beauty! '

chemudupaty
Level 1
Level 1

thank you.

Joseph W. Doherty
Hall of Fame
Hall of Fame

Sherlock Holmes' famous quote, "Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth."

But, when something is "impossible", it's probably a "software defect" (bug).

When it really is "impossible", and not a bug, indeed it might just be improbable, but, alas, if there's more than one possible improbably explanation, which is true?  Further, sometimes the improbable is a "feature".  ; )

Regardless, it can often be difficult to tell the difference between a "software defect" and "feature", but Holmes' like, The Case of the Crashed Program . . .

Decades ago, when I was a contract programmer, about half a year after I finished a contract, I got a call, your program crashed - come back and fix it.  As I had a fairly decent record for low defects in my code, one manager (to protect his identity will refer to as Manager Lestrade) at that business teased me by noting, ha, Sheerluck (to protect my identify), one of your programs actually crashed!

Well, I looked into it it, and my program did crash.  During the post-mortem, for the prior two months my program had been sending to the syslog, it's running low on memory (it might have also noted how low - don't recall).  The day of its "death", it ran out of memory.  (Don't recall, for sure, whether when it hit zero memory it actually "crashed" or first logged something like "cannot continue, aborting processing".)  In any case, I called what happened "a feature".  I also suggested, in the future, operations might want to occasionally check if running programs are throwing any kind of warning messages.  Also, in case of my program, if you had searched for the warning message, in my code, you would have found explicit comments about what to do to increase the memory allocation.

Lastly, I mentioned, if you're wondering why not just allow the program to have all the possible memory it can, first, although hopefully it would never need that much, there's still a limit, and if you hit that one, now what do you do?  Second, while my program is acquiring all this memory, what's the impact to other programs running concurrently?  (BTW, when memory is just acquired, without any kind of monitoring, whether done accidentally, or intentionally, you may obtain "memory leak" results.)

Leo Laohoo
Hall of Fame
Hall of Fame

This is a known bug. 

What firmware is the 9500 on?

16.6.5

I bounced the port and looks like that fixed the issue

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