Output errors and interface resets.

Unanswered Question
Mar 1st, 2007

hi Netpros,

Any idea as to what could be causing output errors and interfece resets on the radio interfaces .. The output interpreter from Cisco does not show any information about the radio interfaces

please see this output after clearing the counters

Dot11Radio0 is up, line protocol is up

Hardware is 802.11G Radio, address is 0015.c7a8.3d90 (bia 0015.c7a8.3d90)

MTU 1500 bytes, BW 54000 Kbit, DLY 1000 usec,

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

Encapsulation 802.1Q Virtual LAN, Vlan ID 1., loopback not set

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

Last input 00:00:07, output 00:00:00, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/962/0 (size/max/drops/flushes); Total output drops: 181678

Queueing strategy: fifo

Output queue: 0/30 (size/max)

5 minute input rate 4000 bits/sec, 6 packets/sec

5 minute output rate 1000 bits/sec, 1 packets/sec

39213813 packets input, 3905641263 bytes, 0 no buffer

Received 53803 broadcasts, 0 runts, 0 giants, 0 throttles

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

0 input packets with dribble condition detected

21236022 packets output, 3766719027 bytes, 0 underruns

11617 output errors, 0 collisions, 25 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

Any input is much appreciated.

I have this problem too.
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Normally, the interface resets occur if the particular device has reboot for several times. This might be due to some power problem. Any fluctuations happened in your netwrok to reset the devices?. Output errors occur due to several reasons like the IOS unable to output the [acket to a non-existence structure.

Looking at the output you have sent, I think it is collected over a long period of time. Your output packets to output error ratio is 11617/21236022 which I think is an acceptable one. I dont think it is operating in a faulty way.

Fernando_Meza Wed, 03/07/2007 - 17:33

Hi .. thansk for your reply

The output is from an access point which has not been rebooted however has experienced several radio interface resets. The output errors are during a period of about two weeks as the counters were recently cleared.

We are performing a complete wireless analyisis on this site to identify what is casuing the above issues.

Cheers,

wbenton-0 Wed, 04/04/2007 - 16:41

Let's take a look at what you're worried about: 11,617 output errors divided by 21,236,022 packets output = 0.05% loss. Not really much to worry about there.

As for the 25 interface resets, that's one reset for every 849,441 output packets. Again, nothing really to worry about, but one does wonder why those numbers are not zero.

So how about taking a closer look at the following line you reported:

Input queue: 0/75/962/0 (size/max/drops/flushes); Total output drops: 181678

Notice in particular the "Input queue drops = 962" and more importantly, the "Total output drops = 181,678". You can find detailed troubleshooting information about these problems at: http://www.cisco.com/warp/public/63/queue_drops.html to help you figure out what the actual problem is and whether or not it can be rectified by fine tuning your parameters.

FYI: Here is a standard definition of Output related errors: (taken from http://www-commeng.cso.uiuc.edu/uiucnet/reports/glossary.html )

Output Errors

- Output errors are the sum of all the output errors that occur on an interface.

Out Success With Retry Errors

- Out Success With Retry errors are output errors which indicate that a frame successfully transmitted after one or more collisions. Out Success With Retry Errors are the number of frames that experienced a a collision and retransmit before success. The total collisions divided by the number of Out Success With Retry errors will provide the average number of collisions per packet transmitted with collisions.

Out of Window Collisions Errors

- Out of Window Collisions are a type of output error. Out of window collision errors occur when a frame in the process of being transmitted collides with another frame. This error usually occurs either when some interface on the network fails to defer or the network has too many stations. (See Late Collisions.)

Output Discard Errors

- Output Discards are output errors that occur when the router has to throw a packet out instead of queuing it for transmission on the Ethernet. Output discard errors usually indicate that the network has more traffic than it can handle. They may also indicate a software discard such as no route to destination.

Output FIFO Overrun Errors

- FIFO Overruns are a type of output error. Output FIFO Overruns occur when the output queue in the adapter underflowed while putting a frame on the wire. This problem occurs when the interface is not receiving bits of the frame fast enough.

Walt

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