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Wireless & Mobility · Advanced

Distributed Interframe Space (DIFS)

The interframe space non-QoS stations wait before contending: SIFS plus two slot times.

Definition

DIFS is 34 microseconds for OFDM in 5 GHz and 50 microseconds for DSSS. QoS stations use AIFS instead. A station must sense the medium idle for DIFS before starting backoff.

Exam tip

DIFS = SIFS + 2 slots.

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