network_PID [MPEG-2 Semantics]
The network_PID per MPEG-2, is an optional field that, when the program_number is equal to 0 in a PAT loop entry, signals the packet id where the Network Information Table can be found.
Use or presence of this field is NOT permitted in ATSC-compliant transport streams.
See: Program Association table (PAT) and network_PID field in PAT and program_number.
See Also: DVB Network Information table (NIT)