[ath9k-devel] Retry control & iwconfig

[Olivier Marce <Olivier.Marce@alcatel-lucent.com>]

Hi,
thanks Pradeep and Paul.

I investigated on this.
But as this time, I'm unable to make a link working with no_ack, even if 
I fix the rate.

The environment is crowded, but not so much. With ACK (iw <dev> set 
noack_map 0 to be sure), for a iperf 10 sec long test, I found only 43 
retry packets over 19k TCP packets.

As soon as I set noack (iw <dev> set noack_map 9), the iperf test does 
not work at all. I'm able to see only 2 packets coming from the iperf 
client over 15 seconds of capture.
The same when fixing the rate (iwconfig <dev> rate 11M), the same with 
1M rate.
The capture done at the 2 ends (AP and STA) are consistent.
This is the same with ping, it does not work (98% packet loss)

Other observations :
- the ACK are well transmitted in the 2 directions
- same behaviour if RTS/CTS on or off

Did someone make a link with no_ack work ? In which condition ?

Regards

On 31/03/2014 12:27, Paul Fuxjaeger wrote:
> On 29.03.14 19:32, Pradeep Reddy wrote:
>>
>> I think, fixing the data rates to make it behave better.
>
> I think so too, maybe minstrel does something very unclever in context
> of NO_ACK being set (like sticking to a very high MCS). Or this is
> simply what we get when turning off (fast!) mac-layer retransmission in
> a busy environment and using TCP over that very leaky pipe then.
>
> -paul
>
>

-- 
Olivier Marc?
Alcatel-Lucent Bell Labs France