The SEQ field in the 802.11 MAC frame represents what?

The SEQ field in the 802.11 MAC frame represents what?

• A. Fragment number / Sequence number of each frame
• B. Frame length
• C. Priority level
• D. Time to live

Answer: (A)

In the 802.11 MAC header, the Sequence Control (SEQ) field is used to track the order and grouping of frames, especially when a single logical frame is split into fragments. It combines the Fragment Number (4 bits) and the Sequence Number (12 bits). The sequence number identifies all frames that belong to the same MSDU, while the fragment number indicates which fragment of that frame a particular fragment is. This enables proper reassembly at the receiver and helps detect duplicates. So the SEQ field represents the fragment number and the sequence number of each frame. The other options don’t fit: frame length isn’t carried here, TTL is a IP-layer concept, and priority is handled by other QoS fields if present.

In the 802.11 MAC header, the Sequence Control (SEQ) field is used to track the order and grouping of frames, especially when a single logical frame is split into fragments. It combines the Fragment Number (4 bits) and the Sequence Number (12 bits). The sequence number identifies all frames that belong to the same MSDU, while the fragment number indicates which fragment of that frame a particular fragment is. This enables proper reassembly at the receiver and helps detect duplicates. So the SEQ field represents the fragment number and the sequence number of each frame. The other options don’t fit: frame length isn’t carried here, TTL is a IP-layer concept, and priority is handled by other QoS fields if present.