In a segmented WLAN, how do mobile clients maintain connectivity when roaming?

In a segmented WLAN, mobile clients maintain connectivity when roaming primarily by deploying all access points (APs) on a single flat IP subnet. This setup allows devices to move seamlessly from one access point to another without requiring a change in IP address. When a mobile client roams between different APs, it can retain the same IP address, which is crucial for uninterrupted connectivity, especially for ongoing sessions like Voice over IP (VoIP) calls and video streaming.

Using a flat subnet means that all devices within the same network segment can communicate directly without needing to route traffic between different subnets. This reduces latency and maintains the session state, as clients do not need to re-establish connections or go through additional steps that would be necessary if they switched subnets or had to change IP addresses.

The other options, while they may have relevance in specific contexts or setups, do not directly address the primary mechanism by which roaming clients maintain uninterrupted service in a segmented WLAN environment. Static IP addresses can complicate mobility due to their fixed nature, multiple VLANs typically support segmentation and may require additional handling for roaming, and connecting to a different network would mean losing connectivity with the original network's resources.