Deploying and Troubleshooting Cisco Wireless LAN Controllers

Chapter 9. Mobility

A mobility event occurs if a client roams between access points (AP) or between controllers. If the wireless LAN (WLAN) is secured, 802.1x or Wi-Fi Protected Access (WPA), the client must reauthenticate to comply with the 802.11i IEEE standard. You want this process to have low latency and appear as transparent to the user as possible while still maintaining security. If this process happens fast enough, it is considered a seamless roaming event.

Controller mobility addresses two key issues:

After the introduction of 802.1x-key-handshakes and 802.1x/ EAP authentication on top of the legacy 802.11 protocol, it is mandatory ...