Unicast packets stop being transmitted to a particular station, under load, when WPA2 is enabled

Ben Greear greearb at candelatech.com
Sun May 11 20:09:21 PDT 2014

On 05/11/2014 06:57 PM, Avery Pennarun wrote:
> Version: 3.15-rc1 and ath10k-stable-3.11-8 (both via backports to kernel 3.2.26)
> Firmware: 10.1.467.2-1
> Steps:
> - Configure ath10k as AP on channel 149, width 80 MHz, WPA2 encryption
> - Connect my 2009 macbook
> - Start a ping of in the background from my macbook
> - Generate some traffic.  The trigger varies, but running uTorrent or
> quickly opening a lot of background tabs in Chrome usually seems to
> set it off within a couple of minutes.  iperf and isoping don't seem
> to cause any trouble.
> Expected:
> - ping keeps pinging
> Actual:
> - tcpdump on the ath10k host shows ICMP requests coming in, and
> responses going out.
> - tcpdump on the macbook shows ICMP requests going out, but no
> responses coming back.
> - tcpdump -I (radiotap mode) on the macbook is a little hard to
> understand since it's encrypted, but it shows some packets coming out
> of the ath10k (broadcasts, I think) but no unicast packets to the
> macbook.
> - tcpdump on the macbook *does* show broadcast packets arriving.  For
> example, ARP requests and "ping -b" (my local subnet IP
> address) get through.
> - Disconnecting and then reconnecting the wifi on my macbook fixes the
> problem until it next triggers.
> - Other STAs connected to the AP are not affected when the one STA
> isn't able to communicate (although each one has the potential to
> trigger the problem)

Can you reproduce with any other type of station

Also, have you tried sniffing with a third device to see if
the AP actually puts the ICMP responses on the air?


Ben Greear <greearb at candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

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