Bit Field Guide

Source Port SrcPort

Transport 2 octets UDP datagram unverified

The sending endpoint's port. May be zero when no reply is expected.

Where it sits

UDP Datagram > Source Port

Open in the explorer — UDP over IPv6, in a QoS Data frame
Open in the explorer — UDP over IPv4, in a QoS Data frame

Accuracy

Clause: RFC 768
Byte order: big-endian — network byte order
Verified: Not verified against the standard. Treat this as a claim, not a fact.