I have a WLC (WLC#1)that has the maximum number of APs connected to it. The APs and the WLC are part of the same Management subnet. Therefore, all the LWAPP tunnels from the APs go over the Management subnet to get to the WLC. In addition, I am using AP Groups so that the APs are using different wired VLANs (to reduce the size of the b'cast domains.)
We are adding more APs to the wireless design so we will be adding a new WLC (WLC#2) to accomodate the additional APs. The new WLC will also be on the same Management VLAN and both of the WLCs will be part of the same mobility group to accomodate roaming.
Question #1: If the first (original) WLC#1 fails, will all/some of the APs automatically failover to the new WLC (WLC#2) even if I don't have WLC#2 configured as the secondary WLC in the AP config? Is there a way to stop the APs from failing over to WLC#2?
Question #2: If the APs from WLC#1 will failover to WLC#2, what will happen to the APs from
WLC#1 that were configured with an AP Group if no AP Groups are configured on WLC#2? Will they just use the default SSID-to-Interface mapping configured on WLC#2? My concern here is that all of the APs from WLC#2 will connect to WLC#2 and they will all use the same VLAN. When clients start connecting, we may run out of IP addresses since the VLAN IP subnets were not designed to handle all the APs in the site.
From what I'm getting from your comments is that you don't have a true redundant solution.
Question #1: All ap's will fail to the new WLC if you do not reach the limit on WLC #2. Unless you remove the WLC #2 from the mobility group, then the ap's will not join WLC #2.
Question #2: If you have the WLC on the same mobility group the ap's will failover to WLC #2. What ever you have configured on WLC #2 for that SSID, it will map to that interface. You will run out of address space if that is how your WLAN was designed.
You would be better off having both WLC being able to handle all ap's so that you can configure them almost identical... I know.. too late for that, but then you could of split the load by floors (floor 1-5 WLC #1, floor 5-10 WLC #2)