Sorry, but I have to point out that 0 dBm is not low. It's only 15 dB less than typical Tx power, but it's 60 to 65 dB higher than typical cell boundaries.
-----Original Message----- From: James Michael Keller [mailto:[email protected]] Sent: Friday, August 14, 2015 10:15 AM To: Chuck Enfield <[email protected]>; [email protected] Subject: Re: [WIRELESS-LAN] Exclusive 2.4 Ghz and 5 Ghz SSIDs On 08/13/2015 05:15 PM, Chuck Enfield wrote: > I suspect you're that ARM can be made to work, but the question is how > to do it. Aruba doesn't tell you what the various indices should be, > they just say that they vary with deployment density. Ask the > question on Airheads and you get: > > "95% of the time you do not have to change those parameters. An > explanation of ARM parameters is here:" and then a link to the users' > guide ARM section. > That from an Aruba employee. > > Also, ARM won’t adjust the Tx power down to 0 dBm, which I find is > often the right 2.4 Tx power for really dense deployments, such as > classroom buildings where there's an AP in almost every room. 0 dBm > must be set in the radio profile. > > Before Client Match I considered abandoning ARM entirely. Client > Match and Mode Aware definitely make it worth keeping though. > If the radio needs to be that low, you may as well turn it off and re-use it for monitoring, which is what the Mode Aware option is in Aruba. Then the remaining 2.4 radios around that AP can power up. At this point we only treat 2.4 GHz band as best effort access only. So it ends up forming large cells with a few APs, so most clients that are duel band will prefer 5 GHz without nudging them. In Aruba's case the controller calculates neighbor tables and prunes the APs with the highest managed neighbor count as part of the AP->Air Monitor algorithm. The coverage index setting comes into play there as well, defaults will end up trying to turn off almost all your radios in both bands in a high density deployment. It's really set for 60ft+ separation without obstructions out of the box, so for high density profiles I usually cut the min/ideal in half for 30 ft drop ceiling deployments. This ends up with min Tx 2.4 GHz radios, but all still on normally. That lets them still power up to fill holes for a down AP. However, as folks have said - it's always the details. All the vendors ship with defaults that really are tuned to 1 floor of cube farms as far as I can tell. It would be nice if they had some out of the box pre-sets for different deployment options. In my case with Aruba it's been a few years of dialing things in after reading all the available vendor documentation as well as picking the brain of various consultants that had been in for different parts of deployments to get real world field experience over what random T1 TAC might tell you. The first thing I usually do on a clean controller is set up some high-density and low-density profiles with corresponding settings. Then do some iterative tweaking as needed based on real deployment and RF environment and any client implementation issues (odd device requirements, etc). -- -James ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
