Monitoring Transmit and Receive Error

kian_hong2000 · ‎09-02-2008

We have an monitoring system to monitor all the access points transmit and receive errors.

There are four column name "Receive Error", "Receive Discard", "Transmit Error" and "Transmit Discards".

I have notice that there are a lot of transmit discards packets than the rest of the columns for one of the AP.

Is it normal for the packets of the AP to have transmit discards high?

kian_hong2000 · ‎09-02-2008

I notice that this AP the Dot11 driver runtime (1331728) is very high than normal Access point (78157)

The rest of the process runtime looks equal.

Is this indicate that the Dot11 driver is going to be faulty?

Transmit Discards AP

CPU utilization for five seconds: 0%/0%; one minute: 0%; five minutes: 0%

PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process

22 127 10867611 0 0.00% 0.00% 0.00% 0 Per-Second Jobs

23 218 2173540 0 0.00% 0.00% 0.00% 0 Compute load avg

24 1134632 181178 6262 0.00% 0.00% 0.00% 0 Per-minute Jobs

25 1331728 317947128 4 0.08% 0.02% 0.00% 0 Dot11 driver

Normal AP

CPU utilization for five seconds: 0%/0%; one minute: 0%; five minutes: 0%

PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process

21 238 10867159 0 0.00% 0.00% 0.00% 0 TTY Background

22 101 10867206 0 0.00% 0.00% 0.00% 0 Per-Second Jobs

23 170 2173453 0 0.00% 0.00% 0.00% 0 Compute load avg

24 1125336 181172 6211 0.00% 0.00% 0.00% 0 Per-minute Jobs

25 78157 318443069 0 0.00% 0.00% 0.00% 0 Dot11 driver

scottmac · ‎09-03-2008

As a general rule, discards are done when the target resource is not available.

For a transmit, the lacking resource is the client. For example, if sleep mode is enabled, the AP will store some outbound traffic until the sleeping client wakes up and requests it. If the client drops (times out, turned off, walked off, or goes brain dead), that traffic would be discarded.

Compare the configuration for that AP to other nearby and see if there's some parameter set differently. Also take a critical look at the location of the AP and the expected client traffic; would you be getting a lot of pass-through traffic? or could the clients be switching between this AP and another near by?

What's your best guess as to why this might be happening?

What kind of AP and is it stand-alone or centrally controlled?

kian_hong2000 · ‎09-09-2008

All the indivdual levels have the same number of equally space AP but not much client are using it at that level compare to the AP in other levels where there are lof of clients and with lower transmit errors.

Therefore, it is less likely to switch between the nearby AP. The AP are standalone and all the AP have the same configuration. My guess is the DotRadio is intermittent faulty.

By the way, how to check the number of pass-through traffic?