Disabling "basic rates" For 802.11n or 802.11ac ?

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I'm following the guide described in Aerohive's "High-Density Wi-Fi Design Principles", which recommends disabling the lower data rates. It recommneds setting 18mbps as the basic rate. While this is straightforward for 802.11g 2.4Ghz, it gets confusing for 5Ghz - I only see a section for 802.11a rates (who cares about a?).

To ensure clients only use higher data rates, customize the data rate support for the 2.4 GHz and 5 GHz frequency bands. Configure a fairly high minimum basic data rate in most high-density deployments (18 Mbps for example) and disable all lower data rates. This encourages clients to roam more aggressively to APs with sufficiently strong signal strength to maintain use of their highest data rates, which conserves airtime and increases overall channel and network capacity.

Is there any option for disabling slow rates options for 5Ghz N / AC? There's no details in the document about what to do with the  MCS0-23 rates.

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Posted 4 years ago

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Carsten Buchenau, Champ

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Check any MCS index table for how they translate to data rates, according to spartial streams and modulations used.

For example:

A possible strategy could be to disable all BPSK and QPSK modulations. So, for 11n, this would be MCS 0, 1, 2, 8, 9, 10, 16, 17, 18.

BUT I have never tested this, I usually don't touch the mcs rates.

Check out Andrew's blog and scroll down to the bottom for his comments about mcs rates:
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Andrew MacTaggart, Champ

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for dot ac you can not disable any lower data rates because the MCS map field only supports 3 options
MCS 0-7
MCS 0-8
MCS 0-9

for n
disabling MCS values does not seem to have any effect as evidenced via packet capture

I am pretty certain APs must support MCS 0 -15 for n.

and MCS 0-7 are mandatory for clients

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Carsten Buchenau, Champ

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Uh - thanks for clarifying Andrew!
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Nick Lowe, Official Rep

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I thought that it constrained the rates an AP can transmit at, but not that the clients can use?
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Andrew MacTaggart, Champ

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According to the 802.11n survival guide:

Single stream operation 0-7 mandatory. Wi-Fi Alliance test plan requires 1 stream for clients.

2-stream operation 8-15 mandatory for APs. 

MCS 16 to 76 optional

according to the 802.11n-2009 standard:

MCS 0 through 15 are mandatory in 20 MHz with 800 ns GI at an AP. MCS 0 through 7 are mandatory in 20 MHz with 800 ns GI at all STAs. All other MCSs and modes are optional, specifically including transmit and receive support of 400 ns GI, operation in 40 MHz, and support of MCSs with indices 16 through 76.

so maybe in using 40MHz they can be disabled, but I recall testing and capturing frames from AP that continued to advertise the disabled MCS.

I think Roberto Casula also did some testing somewhere on this forum.