output buffer failures...what? 1

[rfairy]

Can anyone tell me why when I do:

'sho int gig0/1'

I get:

Full-duplex, 1000Mb/s, media type is SX
output flow-control is on, input flow-control is off
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:00, 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 197000 bits/sec, 108 packets/sec
5 minute output rate 186000 bits/sec, 165 packets/sec
199880267 packets input, 530702320 bytes, 0 no buffer
Received 1767313 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 167047 multicast, 0 pause input
1266257982 packets output, 161260882 bytes, 1582401505 underruns
0 output errors, 0 collisions, 2 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
1582401505 output buffer failures, 0 output buffers swapped out


The last line is the one i'm worried about - I am also getting droped packets on the Unix box that is connected to that port. I can't seem to find any info on output buffer failures bar a buffer tuning document from Cisco.

Has anyone see this before, or might have a clue as to a cause?

Thanks

Rich

 

[IPKONFIG]

Your not getting output or receive errors, so it's most likly a code issue. Have you looked up the Caveats for the version of IOS that your running to see if there are issues with the buffers?

"I can picture a world without war. A world without hate. A world without fear. And I can picture us attacking that world, because they'd never expect it."
- Jack Handey, Deep Thoughts

 

[jdel]

The buffer failures refer to the memory buffers that the packets 'wait' in as the processor takes time to think about each packet. (there are 6 small, medium, large, huge, big, and very big - I think) if they fail, the packets have been dropped/retransmitted. you at times will also notice 'buffer misses'. those refer to times that the buffer ran below a set minimum amount of available memory, but did not entirely fail. In low volume you'll never notice it, but in high volume (as you have there) tyou'll notice applications running very slow due to all the retransmissions. I would reference Cisco's recommendations for tuning and/or add more memory to the router. Be very careful with the tuning though, you do not want to draw too much memory away from other processes. as i said before, try to consult Cisco if you can for a recommendation.

 

[davemiller]

in additon to the prior responses, consider verifying the gbics are SX on each end, as well as the fiber optic distance for SX shich should not exceed 880' give/take pending the quality (dB loss) of all fiber optic components.

The errors are just plain high so you have an obvious problem, but in the future reset the counters so you have a timeline relevant to the error counts when you show the interface/port.

 

[baddos]

Does your unix box have incoming flow control turned on?