Wireless Networking Fundamentals & Technologies Flashcards
7 cards from real ACMA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Wireless Networking Fundamentals & Technologies flashcards as text
In 802.11, what is the purpose of the DIFS (Distributed Interframe Space)?
Answer: It is the minimum time a station must sense the channel idle before starting a transmission
DIFS is the mandatory idle period a station must observe before attempting a data transmission using the Distributed Coordination Function (DCF).
Which term describes the technique where an AP steers a dual-band client from 2.4 GHz to 5 GHz to improve network performance?
Answer: Band steering
Band steering encourages capable dual-band clients to connect on the less congested 5 GHz band by manipulating probe responses or association parameters.
What does 'spatial multiplexing' enable in MIMO wireless systems?
Answer: Sending multiple independent data streams over the same channel at the same time
Spatial multiplexing transmits independent data streams simultaneously using multiple antennas, multiplying throughput without requiring additional spectrum.
In the context of 802.11 power management, what is a TIM (Traffic Indication Map)?
Answer: A field in the beacon that indicates which sleeping stations have buffered frames waiting at the AP
The TIM is included in AP beacons and indicates which associated sleeping stations have unicast frames buffered at the AP waiting for retrieval.
Which 802.11 feature allows an AP to direct RF energy toward a specific client to improve signal quality?
Answer: Explicit transmit beamforming
Explicit transmit beamforming uses channel sounding feedback from the client to steer antenna energy directionally, improving SNR at the intended receiver.
What problem does 802.11r (Fast BSS Transition) specifically address?
Answer: High roaming latency caused by full 802.1X re-authentication during transitions
802.11r reduces roaming latency by pre-establishing the security keys with the target AP before the client fully disassociates from the current AP, eliminating full 802.1X re-authentication.
What is the key difference between infrastructure mode and ad-hoc (IBSS) mode in 802.11?
Answer: Infrastructure mode requires an AP to coordinate communication; ad-hoc allows direct peer-to-peer communication
In infrastructure mode an AP acts as the central coordinator for all client communications, while in ad-hoc (IBSS) mode clients communicate directly with each other without an AP.