FRA Flexible Radio Assignment - will not run

[steiostb1]

FRA will not run to calculate COF. DCA interval is set to 10 minuttes interval. Running two 2802 APs on a 8540 WLC with software 8.2.170.0.

After several days, FRA have still not started:

(Cisco Controller) >show advanced fra

FRA State........................................ Enabled
FRA Sensitivity.................................. medium (95)
FAR Interval..................................... 1 Hour(s)

AP Name MAC Address Slot Current Band COF % Suggested Mode
-------------------------------- ----------------- ---- -------------- -------------------- -------------------------
AP0000.0000.0000 40:ce:24:92:44:00 0 2.4GHz None None
AP08EC.F580.2E08 08:ec:f5:96:06:c0 0 2.4GHz None None

Any tips?

Thanks

[Ric Beeching]

Hey very lazy response but can you upgrade to a recommended code like 8.5.140.0 and we can tshoot from there? :-)

[patoberli]

I don't anymore fully remember FRA when it was introduced. But I think you needed 8.3 or newer for automatic functionality. So I also recommend you upgrade to 8.5.140.0 (unless you have APs that aren't anymore supported by >8.2 releases). There FRA works nicely.

[Haydn Andrews]

As mentioned upgrading if possible could help.

How close are the APs?

Going off this statement in the RRM White paper:

https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-3/b_RRM_White_Paper/b_RRM_White_Paper_chapter_01000.html

FRA evaluates 2.4 GHz coverage only and determines if there is overlapping coverage creating interference

Cisco's FRA does 3 things:

• Calculates and maintains a measurement of redundancy for 2.4 GHz radios and represents this as a new measurement metric called COF (Coverage Overlap Factor)

• Manages radio “role” assignment or re- assignment for interfaces that are marked as redundant interfaces

• For Macro/Micro implementations (2800/3800 I models) FRA Manages Client load balancing across dual 5 GHz interfaces (Macro/Micro Transition)

I would guess FRA only comes into play more when you have 3 or more APs, also based on all the examples in the whitepaper are using 3 or more APs

[steiostb1]

Thank you all for responding.

I have connected a total of 3 APs and still FRA is still not running. The APs are placed phyically on top on each other to provoke a high COF number.

We are currently using 8.2.170 on our production WLC, because of old APs.

According to this documentation, FRA is implemented from 8.2MR1: 

https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-3/b_RRM_White_Paper/b_RRM_White_Paper_chapter_01000.html

[patoberli]

I think you need 4 APs, all on the same 2.4 GHz channel. You also need to have DCA enabled with at least U-NII-2 band channels, because FRA will put the second radio only on 5 GHz if there are 100 MHz space between the two radios.