I'm trying to find out how to best replace two active 4404's with a WiSM while providing minimal client downtime, and would appreciate some input on my two solutions to help determine which is best.
The WiSM is currently on the live network with no APs associated. It has different management, ap-manager and interface addresses, all on the same subnets as the 4404's. The WiSM is also configured with a different mobility group and hostnames. Other than that, the configuration is exactly the same between the WiSM and the two 4404 controllers.
The original plan was that on a scheduled downtime I would shut off the 4404's, then change all the WiSM IP addresses and hostnames to match that of both controllers, then reboot the WiSM controllers so the AP's associate to the WiSM with minimal issue.
The only problem with that is, while changing the IPs and such, the wireless network will of course be down.
Another plan is that I restrict all vlan traffic that the WiSM uses (on the LAG port-channels) to ensure nothing can 'see' it, while keeping it online. Then I will change the IP addresses and mobility groups to match that of the 4404's while they are still online. This way when it comes to the cutover date, I can just shut off the 4404's, allow vlan traffic to the WiSM, and then just reboot the WiSM. Downtime will ideally be only a few minutes.
So far I'm leaning toward the second alternative, but what I am not sure of is that this would actually work. From my understanding, with Vlan traffic being blocked on the port-channels I can still talk to the WiSM if I allow only the wism service-vlan to get through, but nothing else will be able to see it (APs, 4404's, etc). This will prevent issues with duplicate IP addresses. Am I correct in my understanding?
Thanks for any input on this.