Payload Length

Network 2 octets IPv6 packet unverified

Octets after this forty-octet header, extension headers included.

Reading a capture

Not the same as IPv4's Total Length, and the difference bites: this one EXCLUDES the header. A decoder that treats the two alike is forty octets wrong in one direction or the other.

Where it sits

IPv6 Packet > Payload Length

Open in the explorer — UDP over IPv6, in a QoS Data frame

Accuracy

Clause: RFC 8200 §3
Byte order: big-endian — network byte order
Verified: Not verified against the standard. Treat this as a claim, not a fact.