CWNA Wireless Network Administrator

Answer - D - You should provide the proprietary layer 3 roaming solution to ensure continuous connectivity when a client station is roaming across layer 3 boundaries.

Key Takeaway: Layer 3 mobility is a superset of Layer 2 mobility. An 802.11 client must perform a Layer 2 roam, including AP discovery, before it can begin a Layer 3 roam. A wireless client can only roam between APs in the same VLAN and with the same SSID. As WLAN deployments expand within an organization, roaming domains might need to scale beyond a single Layer 2 VLAN. The only way to maintain upper-layer communications when crossing layer 3 subnets is to provide either a Mobile IP solution or a proprietary layer 3 roaming solution.