SYNC

Fifty-six scrambled zero bits at 1 Mb/s, for the receiver to lock on to.

Reading a capture

The whole saving lives here. The long preamble spends 128 bits; this spends 56, and the receiver has less time to settle — which is why the short form is less robust at the edge of a cell, not merely less compatible. Scrambled ZEROES here, where the long form scrambles ones.

Where it sits

HR/DSSS PPDU (short preamble) > SYNC

• Open in the explorer — Ack
• Open in the explorer — Association Request
• Open in the explorer — Association Response
• Open in the explorer — Beacon
• Open in the explorer — Compressed Block Ack
• Open in the explorer — CTS
• 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
• Open in the explorer — RTS
• Open in the explorer — Trigger frame

Accuracy

Clause

802.11-2024 §16.2.2.1

Verified

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