Wireless Access

Hi All, 

with the following command I see many RX drops on AP60:

show ap debug counters ap-name 

Interface counters

------------------

Interface          Rx_pkts             Rx_errors           Rx drops             Tx_pkts           Tx_errors  Tx_drops   Resets

---------              -------                  ---------                  --------                   -------                ---------       --------         ------

wifi0                  22721705         0                           20737118           4918620         17931       0                  0

Someone can help me to understand the root cause of the Rx drop counter?

Thanks and Best Regards

Gian 

What version of ArubaOS is this, because that parameter does not match that command...

We have a 6000 Controller running 3.4.5.1 OS.

About your experience what could be the root cause for RX_drops? (Interference, external antennas, antennas cable.....?)

Thanks and Best Regards,

Gian

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@gianti81 wrote:

We have a 6000 Controller running 3.4.5.1 OS.

 

About your experience what could be the root cause for RX_drops? (Interference, external antennas, antennas cable.....?)

 

Thanks and Best Regards,

Gian

---

All of the above.

What is your problem?

I would like to understand the cause of this RX_drops on all APs.

There are some advanced debugs or suggestions to help me?

Regards,

Gian

You're unlikely to be able to identify the root cause that way. In simple terms, the AP is telling you the frame it received was unreadable. Probably the transmission was interrupted, or corrupt by background aspects, but the AP doesn't know why.

If your controller and APs were a lot newer, the spectrum analysis might help. But from a practical standpoint, I'd suggest you're a long way from that being an option!

So, you should look at the following.

1. How many clients are connected on that AP on average? Is it busy? If so, this might explain the drops due to contention.

2. Are all APs doing this, or just one? If it's all of them, it suggests configuration optimization is in order. If it's just a few, that suggest localized issues, maybe interference or noise.

3. What is the physical environment the AP is in? Near a lift, kitchen or industrial equipment? All of these might cause interference and drops.

Start from there, and consider physically visiting the AP and its surroundings if you're not sure.

Thanks for your reply.

Here below the output. In the manual I read that "RX frames dropped" simply is the number of frames that AP dropped. I should find another value (or values) that added make up this number. No ?

Thanks and Best Regards

------------------- Receive Specific Statistics
Last SNR 32
Last ACK SNR 34
Frames Received 60640570
Good Frames 60138494
Bad Frames 502076
Channel Busy 1s 0
Channel Busy 4s 0
Channel Busy 64s 0
Discarded Events 60100259
ARM Scan Frames 0
Rx Data Frames 12627556
Rx Data Bytes 0
Null Data Frames 0
Rx Mgmt Frames 43953398
Control Frames 3557540
Frames To Me 4433067
Broadcast Frames 51279731
Beacons Received 43751610
Probe Requests 110403
Rx Probe Responses 33834
Rx RTS Frames 113652
Rx CTS Frames 9811
ACK Frames 3434077
PS Poll Frames 0
CRC Errors 502076
PLCP Errors 497227
Rx Frames Dropped 52167942
PHY Events 59348699
RADAR Events 0
RX Interrupts 118321325
RX Overrun 0
Rx 6 Mbps 52608340
Rx 9 Mbps 7855
Rx 12 Mbps 132601
Rx 18 Mbps 94273
Rx 24 Mbps 3622889
Rx 36 Mbps 3672536

Rx Frames Dropped is perfectly normal if it is high.  Only "interesting" frames that are unicast are forwarded to the switch, so a high Rx frames dropped could mean alot of broadcat/multicast/management traffic that was observed but  not forwarded.

Instead of digging into counters that could mean multiple things, why don't we talk about your setup?

- Did this ever work?  If so, what changed?

- What clients are you using?

- What encryption are you using?

- How are the access points mounted and how far apart?