Two WLCs manage separate APs and advertise the same SSID on different interfaces; users lose connectivity and change IPs when roaming. What fixes this?

Configuring mobility groups is the correct solution because it allows WLCs to share client context information, enabling seamless roaming between APs managed by different controllers without IP address changes or service interruptions. When WLCs are in the same mobility group, they can exchange client states, security keys, and IP addresses, ensuring clients maintain their session as they move. High availability provides redundancy for a single WLC but doesn't address roaming between separate WLCs. Fast roaming (e.g., 802.11r) improves roaming speed within a single WLC or between WLCs in the same mobility group but doesn't inherently solve the IP address change issue across different WLCs without mobility group configuration. Client load balancing distributes clients among APs but doesn't facilitate seamless roaming between WLCs.