Principles of Synchronous Digital Hierarchy

274 Principles of Synchronous Digital Hierarchy

10.12 Further Multiplexing

So the tributary unit is the entity that is actually packed with other similar

tributary units into the transport module for actual transportation from the

transmitter to the receiver. In the case of E1s, 63 tributary units are multi-

plexed together to form an STM-1 transport module (see Figure 10.17).

In the whole process of multiplexing, it is important to note the changes in

the bit rates, i.e., number of bits per second, as we progress to form the con-

tainer, virtual container, and tributary unit, from E1 tributary. Let us have a

look at them.

10.12.1 Bit Rates

E1 = 2.048 ...