Karthickeyan Prabanandhan is a Senior Test Engineer (CCNP,CWNP) in Wireless Engineering Team currently preparing for his CCIE Wireless lab. In this video series Karthick will explain "How to configure a 11r WLAN using CLI and GUI and show us the 11r roaming " on Converged Access (Cisco 5760 WLC and Cisco Catalyst 3850).
802.11r is also known, as Fast Transition (FT) is the IEEE standard for fast secure roaming. It introduces a new concept of roaming where the initial handshake with the new AP is done even before the client roams to the target AP. The initial handshake allows the client and APs to do the Pairwise Transient Key (PTK) calculation in advance. These PTK keys are applied to the client and AP after the client does the re-association request or response exchange with new target AP.
The FT key hierarchy is designed to allow clients to make fast BSS transitions between APs without requiring re-authentication at every AP. The summary of the key hierarchy is given below. 802.11r eliminates much of the handshaking overhead while roaming thus reducing the handoff times between APs while providing security and QoS. This is useful for client devices that have delay-sensitive applications like voice and video and is key requirement for voice over Wi-Fi.