When Client A roams from AP1 on WLC1 to AP2 on WLC2 across different subnets, this is considered a Layer 3 roam. Unlike Layer 2 roaming where the client's database entry moves with them, in Layer 3 roaming, the client's database entry is copied to the new controller (WLC2). This ensures continuity of service as Client A transitions between access points managed by different wireless LAN controllers. References := (CCNP Enterprise Wireless Design ENWLSD 300-425 and Implementation ENWLSI 300-430 Official Cert Guide Premium Edition and Practice)