Will all the 120 APs will be pushed to the new Code from the WLC simultaneously ?   Yes, 5508 can push it to 500 APs concurrently. See below table https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-5/config-guide/b_cg85/managing_software.html#ID1230   HTH Rasika *** Pls rate all useful responses *** ... View more

Hi Sairam, I would upgrade primary controller to same as secondary & during its reboot AP will go to secondary & being upgraded. Once the primary comes back all of them will come back to primary, by the time APs will have correct image. That is the easiest way to achieve what you want.   If you want to change AP HA, then best way to do it via CLI. Since you have configured both primary & secondary, you have to swap that one time (in order to APs go & register to secondary). Then another time if you want to move them back to primary. So it is double work. Here is the CLI commands that you can use on WLC to achieve it.   config ap primary-base <Primary_WLC_Name> <AP1_Name> <Primary_WLC_MgtIP> config ap primary-base <Primary_WLC_Name> <AP2_Name> <Primary_WLC_MgtIP> config ap primary-base <Primary_WLC_Name> <AP3_Name> <Primary_WLC_MgtIP>   config ap secondary-base <Secondary_WLC_Name> <AP1_Name> <Secondary_WLC_MgtIP> config ap secondary-base <Secondary_WLC_Name> <AP1_Name> <Secondary_WLC_MgtIP> config ap secondary-base <Secondary_WLC_Name> <AP1_Name> <Secondary_WLC_MgtIP>   In your case, if you want to swap it, best way to do it is below. First let secondary value removed (as you want to use same value as primary). If you do this for all your APs via Primary WLC CLI, you will see all those AP go & register to Secondary.   config ap secondary-base " " <AP1_Name> 0.0.0.0 config ap primary-base <Primary_WLC_Name> <AP1_Name> <Primary_WLC_MgtIP>   Once Primary upgraded, you can do below   config ap primary-base " " <AP1_Name> 0.0.0.0 config ap primary-base <Primary_WLC_Name> <AP1_Name> <Primary_WLC_MgtIP> config ap secondary-base <Secondary_WLC_Name> <AP1_Name> <Secondary_WLC_MgtIP>   I would not worry too much about load, wihin 5-10min all your AP should be able to move from one to another (since code mismatch APs have to download image & reboot)   HTH Rasika *** Pls rate all useful responses *** ... View more