Wireless Access


802.11ac basics

The attached FAQ covers the basics of 802.11ac.  Please respond to the thread if there are any questions after reading the FAQ.


Edited: fixed a typo in Question 7 of the FAQ


Updated 5/31/2012: Updated 11ac ratification information.


Updated 6/27/2012: Fixed a broken link in the TOC and clarrified software 11ac upgrade questions.


Re: 802.11ac basics

Great link! Thanks a lot :)

Samuel Pérez


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Community Manager

Re: 802.11ac basics



Just published a blog on the topic, including an interview with our in-house expert on the topic - Peter Thornycroft, aka. pthornycroft - from Aruba's Office of the CTO. Here it is: 





Super Contributor II

Re: 802.11ac basics

This fact might be misleading.


12. Will 802.11ac be backwards compatible?

Yes. 11a/b/g/n devices will be able to connect to 802.11ac radios.


I believe only 11a/n devices will be backwards compatible with 11ac radios.

Most APs will come dual band with an 11n2.4 radio for 11b/g compatibility.


What do ya'll think?

Sean Rynearson

Re: 802.11ac basics

You are correct in that the standard for 11ac is 5 ghz only.  But when we talk with some of the radio vendors, it sounds like they will be porting some of the 11ac features to 2.4 as well.  I wouldn't be surprised if 256-QAM and wider channel bandwidths made it to 2.4 ghz.  The details are still a little fuzzy.


Even if no 11ac features make it into 2.4 ghz, the new APs would be 5 ghz 11ac and 2.4 11n.  Which means both 2.4 and 5 ghz 11n devices will be able to connect without any problems.  Existing wifi radios will continue to work on the next generation of APs.

Re: 802.11ac basics

I'm confused about the .11n backwards compatibility. Will .11n clients have to connect on 2.4ghz instead of 5ghz? It sounds like .11ac and .11n clients may not co-exist on 5ghz because of the wider channel support.
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Re: 802.11ac basics

currently clients coexist on the 5ghz band also when there are dual channel en single channel clients, ac will just increase the number of channels you can bundle, i don't see why it would cancel eachother out.

Re: 802.11ac basics

Good point, boneyard.  I was not aware that 20mhz and 40mhz clients can coexist, so you're logic makes sense.

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Occasional Contributor II

Re: 802.11ac basics

Can 802.11ac AP co-exist with 802.11n AP?

New Contributor

Re: 802.11ac basics

In FAQ#12 the 11b should be removed, 11ac works only in 5GHz.

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