• By Howard - edited: March 21, 2015

    For installations installing ac hardware, what BASIC rates are being enabled ?   What rates are being completely disabled ?

    Not hypothetically.  What are some peoples actual experience with this.  I have read posts from Mathew Gast and even good old Devinator, but have not seen too much recent material.  

    Most start out by saying to just leave the 2.4 GHz completely.  That's fine for ac, as its only in the 5 GHz band so that's already decided.

    Also, how well have 80 MHz wide channels been working out ?  How about their range ?  I would expect the range to be poorer and roaming to be nearly impossible compared to 40 MHz n or ac.  I would also think that even single stream 80 MHz ac to be impossible on DAS systems.

  • I'm also very interested in the answer to these questions, Howard.  I actually just ordered my first 802.11ac Access Point for home, and I'm looking forward to get some practical experience with the 80MHz performance.


  • Previously, I had thought that "ac" rates could be dialed-in (ie set to disabled, supported, or basic) on a one-by-one basis.      But that is not true.

    If for example, MCS 7 is enabled, that means by definition, MCS 0-6 are automatically enabled.     But it is still possible, on Enterprise AP's, to selectively set the Basic and Supported  Rates for the Legacy "a" rates.

    I have read several recommendations to set the Lowest Basic rate to 24 or even 36 Mbps.

    Haven't yet tried this myself, but I hope to shortly.

    Let us know what you find on your hardware.    I'll be testing a Motorola "ac" AP. 

  • Hi Howard,

    In the cisco world and with many other major vendors, support for greenfield is not an option. A single legacy rate is required therefor meaning in this case of 802.11ac you need to enable for example 24,36,or 54 PHY as mandatory. The remaining MCS rates are supportive. Speaking to MCS rates, what I can say its a challenge and a mess at the same time. Ive seen in our lab testing clients handling of MCS rates, 20-40-80 Mhz channels, rate shifting etc is a complete mess. LOL. Keith Parsons even mentioned a few times the clients handling of 11ac is inconsistent in downshifting and how bandwidth size is chosen. 

    I have to disagree with the mentions of leaving 2.4 GHz. It is a very viable medium and still in use today and will be in the future. It really all depends on the channel use, applications and devices. Channel use being a big one. 

  • By Howard - edited: April 2, 2015

    Thanks Guru.

    My company has dozens, if not hundreds, of customers that still use the 2.4 GHz band, and from what I have seen, they don't plan on changing.   Not everyone is streaming data !

    According to what I have read, including Mathew Gasts' 802.11ac book, Greenfield is not supported with 'ac' -  although I have seen one radio manufacturer's specs say that it is a configurable option with their new 'ac' radios.

    There are so many possibilities, and design philosophies, that I imagine that there won't ever just be one BW selection, or rate shift plan.   However, I do expect that different AP manufacturers will soon publish reports on how their AP's algorithms work better than all the rest.  It would be nice  to see a truly unbiased test (ha ha) with multiple AP's and client device types. 

    I can see new installations planning for, and successfully using 36 or 54 Mbps, as the minimum Mandatory (Basic) rate, but I am betting that some older sites will not work well at 24 Mbps, and need to use an even lower rate .

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