I am installing a new 4404 controller and I want to simply move the APs that are associated with my current controller to the new controller once installed.
The plan is to change the DHCP server once my new WLC is ready and change the option 43 IP address from the old controller to the new controller. This sounds quite simple to me.
I know that the LWAPP flash on the AP sometimes gets stuck, and all of the APs are consealed above the ceiling and would be a nighmare to pull down the ceiling and console into all of them.
Should the original plan of just changing the DHCP server option 41 to the new WLC IP address work OK, or do I run a big risk of having to get ceiling tiles down and all that jazz?
Please can anyone advise me?
Many thx indeed,
Jerome has some good points, the thing is, are you planning on rebooting the ap's so that they get the information from dhcp? If you really don't want that hassel, then like Jerome mentioned, just add the new wlc to the mobility group info (both wlc should have the other) and then change the ap's primary controller to the new lwc. You can do this manually or if you have WCS, push out a template. Make sure you have AP Fallback enabled on the existing wlc so that the ap will know that it has to join the primary.
FIrst of all, if both controllers run the same code, there is no flash issue. Still, the APs tend to remember the previous controller they were connected to, so you might see APs taking a Looong time to join the new controller, but they should eventually join anyway.
A few other ways to do it:
- my favourite: add the new controller to the same mobility group as the first one and make them know each other (adding each controller IP and MAC to the other one). Then define this new controller as the primary controller on all APs, reboot them.
- Variation: if you use WCS, use a template to push the APs to the new controller.
- If you replace the controller, configure the new one with the same IP addresses as the former one (and of course remove the old one before plugging the new one).
- You can also put one of the APs in the same subnet as the new one, and use OTAP to have the others join it.
Keep in mind that option 43 is just one way, among others, for the AP to discover as many controllers as it possibly can before choosing which one is the best to join. Changing option 43 will not remove the info about the old controller from the AP memory, so it might be more efficient to push them to the new one more gently... but the option 43 technique should work anyway...