On 11/04/15 15:12, Kevin McCormick wrote: > Cisco says to use 40 Mhz channels on 5 Ghz if you have the channels to > support it. > > We have more than enough channels in our deployments to avoid overlap, > so we have 40 Mhz turned on. > > We are also disabling 11b and 11a data rates to weed out the few slower > older clients. > > Since almost all our 5 Ghz clients are 11n or 11ac they will all take > advantage of the 40 Mhz.
I've been running 40Mhz channels without any noticeable problems, 80% of devices are in 5GHz. Particularly since we still have a lot of iPad 4s, which are only 1x1:1 but do support 40MHz channels. > I agree with Cisco, if you can use 40 Mhz without any serious impact, > make the change from 20 to 40. > > http://www.cisco.com/web/strategy/docs/education/cisco_wlan_design_guide.pdf Also 802.11ac is much better at sharing wider channels with neighbouring APs, so you may as well enable 40MHz or even 80MHz channels, since if the overlapping channels are busy the client will tell the AP and they'll fall back to a narrower bandwidth. But otherwise you'll benefit from the improved speeds. http://www.cisco.com/c/en/us/products/collateral/wireless/aironet-3600-series/white_paper_c11-713103.html#_Toc383047848 http://chimera.labs.oreilly.com/books/1234000001739/ch03.html#medium_access_procedures http://chimera.labs.oreilly.com/books/1234000001739/ch05.html#section-channel-selection -- James Andrewartha Network & Projects Engineer Christ Church Grammar School Claremont, Western Australia Ph. (08) 9442 1757 Mob. 0424 160 877 ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
