Free Cisco 300-425 ENWLSD Actual Exam Questions - Question 15 Discussion
authentication SSIDs configured. After fail over, all APs are broadcasting all SSIDs, but the clients are
assigned IP addresses from a different subnet. The WLANs on both WLCs are configured with the
same dynamic interfaces. Which feature must be incorporated in the wireless design of the second
controller?
Makes sense that VLAN Select (C) is the key here. Since both controllers use the same dynamic interfaces, without VLAN Select on the backup, the VLAN-to-SSID mapping won’t adjust after failover, causing clients to land in the wrong subnet. AP Groups (B) wouldn’t fix this since all APs already broadcast all SSIDs, so it’s not about which APs send which SSIDs. It’s a VLAN assignment issue, so adding VLAN Select on the second controller is needed to keep the VLAN mappings consistent and ensure clients get correct IPs after failover.
It’s C because VLAN Select handles VLAN mapping per SSID, fixing subnet issues after failover.
Not B, AP Groups control which APs broadcast which SSIDs, but here all APs broadcast all SSIDs after failover. The issue is the VLAN assignment, so VLAN Select (C) is needed to map SSIDs to the correct VLANs on the backup controller.
C VLAN Select lets the backup controller map SSIDs to the right VLANs dynamically, so clients get the correct IP subnet after failover. Without it, all SSIDs broadcast but with wrong VLANs.
The problem looks like VLAN mismatch after failover, so VLAN Select (C) should be added on the backup controller to assign correct VLANs per SSID. This avoids clients getting wrong subnets.
B The issue seems related to how SSIDs and their VLAN mappings are handled during failover. AP Groups let you assign specific APs to different WLAN-to-VLAN mappings on each controller, which helps avoid clients getting IPs from the wrong subnet after failover. This fits better than VLAN Select, which is more about trunk VLAN choices. Since the question mentions both controllers have the same dynamic interfaces, AP Groups can customize what each AP broadcasts on the backup controller, keeping client IP assignments consistent.
Option C makes sense since VLANs control IP subnets for clients.