Is it possible that 2 wireless controllers use the same guest network. We have the following situation 2 floors of a building big separation, there is an existing controller that is used with 16 SSIDs, on the other floor there is also a controller , there is a L2-connection between the floors, there are other SSID's needed on both floors, but the guest should be shared and the customer use 2100 controllers. I would believe that this is possible when you created the users on both controllers, can this work ? Or do we need to create different guest wlan ? It is impossible that both networks each other see over the wireless separation of 15 floors
You can have the WLC's share the same guest subnet, you need to have a dynamic interface on both WLC's that is on the guest subnet. If the wlc is doing dhcp, then you need to split the dhcp scope. If you have a dhcp server, then all you have to do is configure the primary dhcp on the guest interface to point to that dhcp server.
One other thing is that, do you have mobility setup between the two WLC's? You would need this if a guest user associates to an ap on the other wlc due to RF bleed between floors. I would not try to create another SSID, because you already have too many. I try to keep the SSIDs down around 4. The more, the more RF noise.