Sequence Control SeqCtl

Identifies this frame within a sequence, and its fragment position.

Reading a capture

How a receiver detects duplicates. A retransmitted frame reuses its sequence number, which is what lets the receiver drop the copy rather than deliver the same data twice.

Subfields

• Fragment Number — Which fragment of the current MSDU this is. Zero if unfragmented.
• Sequence Number — Increments per MSDU, wrapping at 4095. All fragments of one MSDU share it.

Where it sits

QoS Data MPDU > Sequence Control

• Open in the explorer — TCP over IPv4, in a protected QoS Data frame, aggregated
• Open in the explorer — Association Request
• Open in the explorer — Association Response
• Open in the explorer — Beacon
• Open in the explorer — Four-way handshake message 1
• Open in the explorer — Four-way handshake message 2
• Open in the explorer — Four-way handshake message 3
• Open in the explorer — Four-way handshake message 4
• Open in the explorer — Probe Request
• Open in the explorer — Probe Response
• Open in the explorer — ARP request in a QoS Data frame
• Open in the explorer — ICMP echo over IPv4, in a QoS Data frame
• Open in the explorer — UDP over IPv6, in a QoS Data frame
• Open in the explorer — TCP over IPv4, in a protected QoS Data frame
• Open in the explorer — TCP over IPv4, in an open QoS Data frame
• Open in the explorer — UDP over IPv4, in a QoS Data frame

Accuracy

Clause

802.11-2024 §9.2.4.4

Byte order

little-endian — least significant octet first

Verified

Not verified against the standard. Treat this as a claim, not a fact.