@GIdenJoe & @UKDanJones  - Thanks for this reply thread. I should say I have used both Airmagnet and Ekahau for designs  and appreciate what I am asking is all based around theory rather than real world.   The area we are currently planning for is a "high'ish" density office with will have a high concurrency of video meetings so the  normal AP planning by coverage alone I feel would not work. So having been given the clients device spec (802.11ac 2SS on 5GHz) and the application usage I was trying to do a quick coffee break calculation on the AP numbers that will then be done for real in Ekahau in a few weeks time. I  could just use the client concurrency of 25 like Cisco and Meraki talk about but wanted to see if planning for application usage would derive a higher number of AP's.  For example (not real world numbers)  if  we have 1 floor with 400 users (assuming they average at 2 connected devices - 1 laptop doing video chat and 1 mobile just background syncing) that would require 32 AP's for 25 max connections . But you say 50% of the users will be on a video chat  (4Mb per call), the other 50% web browsing  (1Mb)  and allowing (0.5Mb for each mobile device background sync) that works out at 1600Mb required so was going to see what Meraki's formula worked that out to be. ... View more

What is the "Addressing and traffic options" you have set for that SSID as 802.11r will be removed as an option if they are set to either "NAT" or "Layer 3 roaming" ?  ... View more