This document discusses Cisco's controller-based wireless LAN architecture and mobility features. It covers:
1) The controller-based architecture uses wireless LAN controllers and access points to centralize management and control of wireless clients. Controllers handle client authentication, security, mobility, and network access across multiple access points.
2) Mobility is enabled through mobility groups, which allow controllers to peer with each other and exchange information to support seamless roaming across controller boundaries.
3) Cisco's technologies like CAPWAP, split MAC, and static IP mobility aim to make wireless roaming fast and seamless while maintaining security as clients move between access points and across subnets.