What does the radio profile parameter "Max Power Backoff" do?

  • 1
  • Question
  • Updated 6 months ago
I noticed that with most recent HM Classic updates we now have an additional configuration option inside the radio profiles, the "Max Power Backoff" setting.

Maybe I missed something, but I couldn't find an explanation anywhere in the Help files nor Release Notes... can anyone briefly explain what this does, how to choose the best value, and what it means if I simply disable this option?



Thanks,
carsten
Photo of Carsten Buchenau

Carsten Buchenau, Champ

  • 356 Posts
  • 117 Reply Likes

Posted 9 months ago

  • 1
Photo of Ben Swaby

Ben Swaby

  • 41 Posts
  • 2 Reply Likes
What version are you on?  
Photo of Carsten Buchenau

Carsten Buchenau, Champ

  • 356 Posts
  • 117 Reply Likes
Hivemanager on-premise (VM) 8.1r2 with HiveOS 6.5r8a and 8.1r2.
Photo of Carsten Buchenau

Carsten Buchenau, Champ

  • 356 Posts
  • 117 Reply Likes
I just checked, I see the same settings in HMOL 8.1r2 as well...
Photo of Brian Powers

Brian Powers, Champ

  • 396 Posts
  • 92 Reply Likes
That should be the amount of power the AP will drop when using ACSP.  If your max Tx power is set to 20, your min Tx is set to 2, based on the options in the (), your max power backoff would be 18, meaning that if the AP saw enough variables (channel utilization, neighbors on same channel, etc.) it could power it self anywhere from 2 to 20.  The default value that existed in prior iterations of the HiveOS code was always 9 backoff and could only be adjusted here recently but only via Supplemental CLI.  
Photo of Carsten Buchenau

Carsten Buchenau, Champ

  • 356 Posts
  • 117 Reply Likes
Thanks Brian - it's what I thought, but I am confused by having both min Tx and max Backoff - it sounds like they make each other redundant....
Photo of Brian Powers

Brian Powers, Champ

  • 396 Posts
  • 92 Reply Likes
Sure.  And I can see how it could be a bit redundant.  I imagine Aerohive is just attempting to give options to cover any form of power setting options that someone might want.  Although I'm not sure what the max power backoff would do/be if that box was unticked (would it default to the usual 9?).  Would also be curious as to which one would supersede the other (would it never go below the min Tx or would it try to drop below it to the limit of the max backoff if it felt necessary).
Photo of Carsten Buchenau

Carsten Buchenau, Champ

  • 356 Posts
  • 117 Reply Likes
Yup :-) And the default settings (as per my screenshot) already present such a case...
Photo of Carsten Buchenau

Carsten Buchenau, Champ

  • 356 Posts
  • 117 Reply Likes
I received confirmation:

When using ACSP, the power will drop from "Max Transmit Power" down to "Min Transmit Power" OR "Max Transmit Power minus Max Power Backoff" - which ever value is HIGHER.
Photo of Franco Gobbetti

Franco Gobbetti

  • 45 Posts
  • 0 Reply Likes
Very interesting post guys, can I ask the same question about HM NG ?

HM NG has  Maximum Transmit Power defined in the Radio Profile and Transmission poewr floor and Transmission Power maxdrop defined in the AP interfaces, the correspondence between HM Classic and HM NG Parameters should be:

"Max Transmit Power" = " Maximum Transmission power"
"Min Transmit Power" = "Transmission Power Floor"
"Max Power Backoff" = "Transmission Power maxdrop"

So in HM NG 

When using ACSP, the power will drop from "Maximum Transmit Power" down to "Transmission Power Floor " OR " Maximum Transmit Power minus Transmission Power Maxdrop" - which ever value is HIGHER.

Correct? thx

Franco