The MPEG Data Stream - Digital Video and Audio Broadcasting Technology - page 62

is possible, e.g. to broadcast information about all available physical chan-
nels within a network (e.g. satellite, cable), making it possible to do away
with the actual physical search for channels.
The NIT contains the following information:

• Transmission path (satellite, cable, terrestrial)
• Received frequency
• Type of modulation
• Error protection
•

Transmission parameters

NIT

PID=0x10;

Table_ID=0x40/0x41;

Repetition time:
25ms …10s

Network_ID;
Version management;

Section_length

Network_descriptors_length

Network
descriptors
loop

for i=0 i<N i++

Descriptor();

Transport_stream_loop_length

for i=0 i<N i++

Transport_stream_ID;
Original_network_ID;
Reserved;

Transport
stream
loop

Transport_descriptors_length

for i=0 i<N i++

Transport
descriptors
loop

Descriptor();

CRC_32

Fig. 3.31. Structure of the Network Information Table (NIT)