[nsp] Catg 3550 "output buffer failures"

[Church, Chuck]

The frames are being switched in hardware, since there are no output queue drops.  But the hardware is attempting to put frames on the wire when it's pretty close to being saturated.  Your 30 average is around 80 mbit, but it only takes a couple millisecond long burst to fill up the hardware interface buffers and cause this error.  It's probably time to add another link (forming an etherchannel) or jump to a gig interface.  I don't think you can tune these hardware buffers at all to buy any additional time.

Chuck Church
CCIE #8776, MCNE, MCSE
Wam!Net Government Services
13665 Dulles Technology Dr. Ste 250
Herndon, VA 20171
Office: 703-480-2569
Cell: 703-819-3495
cchurch at wamnetgov.com
PGP key: http://pgp.mit.edu:11371/pks/lookup?op=index&search=cchurch%40wamnetgov.com

> -----Original Message-----
> From: Konstantin Barinov [mailto:sbr at infonet.ee]
> Sent: Monday, February 02, 2004 10:59 AM
> To: cisco-nsp at puck.nether.net
> Subject: [nsp] Catg 3550 "output buffer failures"
> 
> 
> 
> Hello,
> 
> Maybe anybody is able to explain "output buffer failures" on
> Catalyst 3550? They increase as soon as traffic reaches ~80M.
> 100-200 per minute.
> 
> Thanks!
> 
> 
> br
> --
> Konstantin Barinov
> INFONET AS, Tallinn, Estonia
> 
> 
> 
> FastEthernet0/19 is up, line protocol is up (connected)
>   Hardware is Fast Ethernet, address is 000b.4699.4b93 (bia 
> 000b.4699.4b93)
>   MTU 1516 bytes, BW 100000 Kbit, DLY 100 usec,
>      reliability 255/255, txload 211/255, rxload 222/255
>   Encapsulation ARPA, loopback not set
>   Keepalive set (10 sec)
>   Full-duplex, 100Mb/s
>   input flow-control is off, output flow-control is off
>   ARP type: ARPA, ARP Timeout 04:00:00
>   Last input 00:00:08, output 00:00:01, output hang never
>   Last clearing of "show interface" counters 00:06:17
>   Input queue: 0/75/0/0 (size/max/drops/flushes); Total 
> output drops: 0
>   Queueing strategy: fifo
>   Output queue :0/40 (size/max)
>   30 second input rate 87085000 bits/sec, 23197 packets/sec
>   30 second output rate 82827000 bits/sec, 23502 packets/sec
>      8819547 packets input, 4152638391 bytes, 0 no buffer
>      Received 7 broadcasts, 0 runts, 0 giants, 0 throttles
>      0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
>      0 watchdog, 7 multicast, 0 pause input
>      0 input packets with dribble condition detected
>      9006096 packets output, 4005769332 bytes, 976 underruns
>      0 output errors, 0 collisions, 0 interface resets
>      0 babbles, 0 late collision, 0 deferred
>      0 lost carrier, 0 no carrier, 0 PAUSE output
>      976 output buffer failures, 0 output buffers swapped out
> 
> 
> 
> 
> 
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