Dynamic Airtime Scheduling - Airtime Fairness - 2009 IMAC

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Trying to understand an issue involving Dynamic Airtime Scheduling - Airtime Fairness - with 2009 IMACs

I had several APs with 20% retry errors and the errors for the most part had to do with airtime violations.

In the non compliant report the IMACs appeared as the top violators.

So I enable Dynamic Airtime Scheduling



the error rates have fallen below 10%

The issue is when Dynamic Airtime Scheduling check box is enabled is

That these HT capable IMACs only connect to 2.4Ghz radio.

In an isolated room where the AP had wifi0 2.4Ghz radio shut off, the IMACs could not see the 5Ghz radio. other devices could communicate with the 5Ghz radio.
It's like the IMACs are not seeing the beacon frames from the 5Ghz radio

we have about 40 IMACs purchased in 2009
wifi specs
2.4 GHz, 5 GHz - Switchable
Tx 1 tested Spatial Streams 2.4 GHz
Rx 1 tested Spatial Streams 2.4 GHz
Tx 2 tested Spatial Streams 5 GHz
Rx 2 tested Spatial Streams 5 GHz
40 MHz operation in 5 GHz
HT Duplicate (MCS 32)



This issue appeared in 10.7.5 and with mountain lion 10.8 OSX

So Dynamic Airtime Scheduling is supposed to give HT devices an edge over non-HT devices, not drive the clients to the 2.4Ghz band

or am I missing something

Has anyone else seen this behavior?

would like to add
AP 330
basic rate set to 18Mbps
bandsteering enabled

Cheers
A
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Andrew MacTaggart, Champ

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Posted 5 years ago

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Crowdie, Champ

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Dynamic Airtime Scheduling (http://www.aerohive.com/solutions/tec...) is about ensuring that legacy wireless clients, particularly 802.11b clients, do not have a hugely adverse effect on 802.11n/ac clients when the access point(s) come under load.

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Andrew MacTaggart, Champ

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That is why it is so perplexing
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Andrew MacTaggart, Champ

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we are going to run hardware tests on the IMACs displaying this behavior, I suspect that the issue lies somewhere in the IMAC radios.

Ran through all 40 Imacs and 10 display this behavior.
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Andrew MacTaggart, Champ

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Issue has been figured out, but not entirely resolved

bottom line
2009 IMAC does not support 802.11h



HK country code was updated recently for supported channels in Hive OS



Previous release only displayed unii1 and unii3, which I guess is what China supports.

now running 6.1r2, previously running 6.1r1

Macbook air seems to dynamically change to match the country code settings of the AP, which makes sense for a mobile device.



Channel selection is auto with dynamically changing channels



IMAC would work one day but if channel switched [to non supported channel] the next day it would connect to 2.4Ghz and depending where it was located 2.4Ghz coverage might have been .

When enabling Dynamic Airtime Scheduling, it seemed to point to areas that a client was connected to 2.4Ghz but the conditions weren't very good. Thus they required more airtime, and considered unfair. So I have increase the power settings on 2.4 radios in these areas to accomadate these IMACs

Cheers
A