CWDP Roaming and Client Mobility Flashcards

Which IEEE amendment defines fast BSS transition (FT), reducing roaming latency for real-time applications?

Answer: IEEE 802.11r

IEEE 802.11r defines Fast BSS Transition, enabling pre-authentication with target APs to reduce handoff time below 50 ms.

What problem does IEEE 802.11k (Radio Resource Management) solve in roaming scenarios?

Answer: Provides clients with neighbor AP reports to accelerate target AP discovery

802.11k neighbor reports give clients a pre-built list of APs to consider for roaming, eliminating time-consuming full channel scans.

What is 'sticky client' behavior and why is it problematic in enterprise WLAN design?

Answer: Clients that maintain association with a distant AP despite a closer one being available

Sticky clients stay connected to a far AP with weak RSSI rather than roaming to a closer one, degrading throughput and reliability.

In the 802.11r fast transition process, what is the role of the 'R0 Key Holder'?

Answer: The first AP in the mobility domain that derives the master session key

The R0 Key Holder (typically the original authenticating AP or controller) holds the top-level PMK-R0 from which all roaming keys are derived.

What IEEE amendment enables BSS Transition Management, allowing APs to suggest better APs to clients?

Answer: 802.11v

802.11v BSS Transition Management allows APs to send BTM Request frames suggesting clients move to a better AP.

What minimum RSSI delta between the current AP and a candidate AP typically triggers a client roam decision?

Answer: 5 dB

Most clients require at least a 5 dB RSSI improvement at the target AP before initiating a roam to avoid unnecessary thrashing.