Image difference for 8.5.171.0 for WLC 5508 and 5520

[Noovi]

Hi Guys,

I have one 5508 WLC and other 5520 WLC and they are backup to each other with respect to AP association.

My query is 

5508 have image AIR-CT5500-K9-8-5-171-0.aes

where 5520 is with AIR-CT5520-K9-8-5-171-0.aes

if i do AP pre image download on 5508 WLC so will AP from 5508 will associate to 5520 directly without downaloading image?

Normally if same model of WLC is there then we do pre image download to reduce AP association time

But here as WLC model are different i got confused if AP will again download image or directly associate with WLC?

[JPavonM]

AP image does depend on the AireOS release and not the WLC model so yes, AP will move between controlelrs without downloading new firmwares.

[Leo Laohoo]

The controller firmware is basically an "archive" file (think ZIP, TAR, RAR, GZIP, etc).  Inside this "container" is the controller firmware files plus a host of AP firmware files.