Choose the right one and explain why is the correct and explain each of the alternatives to be selected, explain the function and operation of each of them if applicable.

 

1- The plesiochronous digital hierarchy (PDH)

a)  It is established on 4:1 multiplexing standards common in the USA, Japan and Europe.
b) It was developed for transmission by coaxial cable.
c) It allows rings to be formed using selective aggregation/disaggregation elements that, in a way, act as traffic switches.
d) It is incompatible with SDH since it is based on the establishment of virtual circuits.

e) It supports Ethernet clients but is not suitable for video broadcasting due to its jitter.
f) All the answers are correct.