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Cat3548xl Output Buffer Failures/Overruns

I have users that are timing out of our imaging application. This only happens to users connected to the same switch. This is the only switch with ports that are receiving output buffer failures. Also, the number of buffer failures is identical to the number of underruns. I don't know how to start troubleshooting this. I tried the sho buffer command but I don't think that is helpful. I guess my question is what could the bufferfailures mean? What should I be looking at?

FastEthernet0/3 is up, line protocol is up

Hardware is Fast Ethernet, address is 0006.288c.ae83 (bia 0006.288c.ae83)

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive not set

Auto-duplex (Full), Auto Speed (100), 100BaseTX/FX

ARP type: ARPA, ARP Timeout 04:00:00

Last input never, output 00:00:01, output hang never

Last clearing of "show interface" counters 2d01h

Queueing strategy: fifo

Output queue 0/40, 0 drops; input queue 0/75, 0 drops

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

51928 packets input, 8101226 bytes

Received 645 broadcasts, 0 runts, 0 giants, 0 throttles

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

0 watchdog, 0 multicast

0 input packets with dribble condition detected

394883 packets output, 77720160 bytes, 217 underruns

0 output errors, 0 collisions, 0 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier

217 output buffer failures, 0 output buffers swapped out

1 REPLY
Silver

Re: Cat3548xl Output Buffer Failures/Overruns

If you place the output in the output interpretter

https://www.cisco.com/cgi-bin/Support/OutputInterpreter/parser.cgi/tmp

it shows

Interface FastEthernet0/3 (up/up)

WARNING: Interface FastEthernet0/3 is up/up but keepalives are not set (set to 0 secs)

so the interface could be spoofing.

TRY THIS: Set the keepalive timer to an integer value using the 'keepalive'

interface configuration command. The default is 10 secs.

WARNING: The counters are older than 24 hours and may not accurately reflect

the current status of this interface.

TRY THIS: Reset the counters using the 'clear counters' command and wait a few

minutes to resubmit the output to Output Interpreter.

WARNING: There are 1 or more reported underruns.

This indicates the number of times that the transmitter has been running

faster than the router can handle.

TRY THIS: Monitor the level of underruns over time. If they continue

increasing, consider buffer and queue tuning or upgrading hardware.

REFERENCE: For further information, see: Troubleshooting Ethernet and

Buffer Tuning

INFO: There are 1 or more reported output buffers failures.

If outgoing interface buffers are not available, an output buffer failure is

reported. If an interface buffer is available but the Transmit Queue Limit is

reached, the packet is dropped. However, if 'transmit-buffers backing-store'

is enabled, the packet is placed in a System Buffer (which has to be obtained

from an appropriate Free-List), and enqueued in the Output Hold queue for

future transmission at the Process level, and an Output Buffer Swap is reported.

You may also want to hard code your speed and duplex settings. also ensure you set keepalives as stated above

hope this helps

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