Installing newer lightweight AP image than WLC's default AP image.

[sardarjion]

This maybe a very basic question but I wanted to get some insights. 

Whenever an AP joins a WLC, the WLC has a copy of the AP's Lightweight image and it gets downloaded. In my experience, it doesnt matter what image version is loaded on AP, the WLC will download the image to be in sync. 

However, I see that on Cisco website, there are newer images released for example Software Download - Cisco Systems. I am wondering how can I install this and then join the WLC because this image will get overwritten by default WLC image. The WLC in my testing is 2504 if it matters. 

Could someone help me understand this problem. Thanks. 

[Kasun Bandara]

@sardarjion hi your are correct. WLC will install its Light weight OS to AP. what is the AP model? and what version are you planning to use?

[sardarjion]

WLC: v8.5.182.0 released on 31-Aug-2021

AP 2702i: 15.3.3-JPP ED released on 30-Mar-2023.

[Kasun Bandara]

@sardarjion your WLC 2504's last supported OS is 8.5.182.0. you cannot go beyond that in same WLC. if you need to use newer AP version (15.3(3)JK9 for AireOS) you need to buy new WLC which supports that version. new conroller can be 3504. but recommendation is to move with 9800 WLCs. the version you mentioned (15.3.3-JPP) is not for AirOS controllers.

[sardarjion]

But the question still remains, even if I find a image which is supported by the WLC, the WLC will override the installed image so what is the point of Cisco releasing these images separately? These should be part of the WLC release isn't it?

Take a look at this Release 15.3.3-JK6 ED which is released around same timeframe 27-July-2021. Even if I want to keep this one, I cannot because WLC will override it. 

[Leo Laohoo]

JPP is IOS-XE version 17.11.1.  

[Kasun Bandara]

@sardarjion as i mentioned above, 2504 only support till 8.5.182. for that you can only have up to 15.3(3)JF15 AP version. you cannot go beyond with 2504 WLC.

[sardarjion]

Thanks, so if I go install any version lower than 15.3(3)JF15 it will still get overwritten by WLC depending on the version of WLC software? Is there a way to force the APs to be on a particular version because I still cannot wrap my head around as to why Cisco would release these images instead of packing it in WLC software. 

[Kasun Bandara]

@sardarjion normally WLC push its own version to AP always. you need to understand the architecture. WLC is the one who manages all APs connected to it. every policy, SSIDs, security settings, etc. so WLC need to have good understanding about every AP and AP needs to compatible with WLCs capabilities. so each need to be in same recommended version. 

when new OS release to AP or WLC, that can include optimizations, new features or feature deprecations. if you used incompatible version of WLC, WLC may not know how to send commands to AP about old/new features. that's why it need to be same. every WLC release packaged with relevant compatible AP OS version. since WLC and AP are different products, OS versions are different and development teams may different. they use different hierarchy to maintain different product lines. but to make sure compatibility is there, they listing compatibility charts to avoid confusion. 

same thing happens with other products too. like calla managers, Routers, Firewalls, there are different components with different firmware versions.

[Flavio Miranda]

Hello

 It does not happen exacly as you think. For example, if the image on the Access Point is the same as the one stored on the wlc, the AP will not replace.

 I can afirm that  because some times ago I worked in a Bug with Cisco TAC related to AP 3800. Then, Cisco send me an specific code for my APs. I installed, the problem was fixed and the AP kept using this code útil Cisco add it as official code on the WLC. During this time, I could reload the AP just  fine and the same locally installed code as used.

But, as I said, the version was the same between AP and the one stored on the WLC. If the version is different, then, the upgrade or downgrade will happen.

So,  for your question, it would be possible but both AP and WLC should have the same version.

[sardarjion]

Ok, but why would Cisco release the images for AP with so many versions if they need to be in sync with WLC? Is there a use case where you can install these images and still work with WLC? To me it makes sense if Cisco would release just a recovery image which can communicate with WLC and download the correct image from WLC. 

[Flavio Miranda]

honestly I dont know the goal behind it although I believe they must have a reason of course. 

But, if we have a WLC in place, we dont need to worry about install indiviadual code for AP.  My point about your thread was just to clarify that the AP image can exist independently from the WLC as long as they are on the same version.

[Rich R]

So there are a few reasons why the images are made available to be installed independently of the WLC:

- Pre-staging APs so that they don't need to download the code when installed - they can simply join the WLC and start working immediately.

- If you have an AP with very old code installed which is not compatible with the code on the WLC it won't be able to join and download from the WLC, therefore your only option is to pre-install the software.

- Flash corruption of AP causes loss of software - again only option is to pre-install.

One correction to above comments - do NOT use 8.5.182.0 - refer to field notice below - some APs will not be able to download.  Use 8.5.182.7 - link below.