Which statement accurately describes SIFS in relation to other interframe spaces?

Which statement accurately describes SIFS in relation to other interframe spaces?

• A. Short Interframe Space (SIFS) has the highest priority.
• B. DIFS has the highest priority.
• C. EIFS has the highest priority.
• D. PIFS has the highest priority.

Answer: (A)

Interframe spaces set the order in which stations can access the wireless medium, giving different frames different waiting times. The shortest of these spaces has the highest priority because it minimizes the delay before a response or next transmission. SIFS is the smallest interframe space, so it carries the highest priority. This short wait is essential for time‑critical exchanges like an ACK or CTS that must follow immediately after a data frame to keep throughput high and avoid wasting airtime. Other spaces are longer to support different functions: DIFS is used for normal CSMA/CA transmission opportunities, giving stations more time to sense the medium and back off; PIFS is used in PCF scenarios and sits between SIFS and DIFS in priority; EIFS is the extended wait used after certain errors and is the longest, delaying access further.

Interframe spaces set the order in which stations can access the wireless medium, giving different frames different waiting times. The shortest of these spaces has the highest priority because it minimizes the delay before a response or next transmission.

SIFS is the smallest interframe space, so it carries the highest priority. This short wait is essential for time‑critical exchanges like an ACK or CTS that must follow immediately after a data frame to keep throughput high and avoid wasting airtime. Other spaces are longer to support different functions: DIFS is used for normal CSMA/CA transmission opportunities, giving stations more time to sense the medium and back off; PIFS is used in PCF scenarios and sits between SIFS and DIFS in priority; EIFS is the extended wait used after certain errors and is the longest, delaying access further.