Frame relay networks, where is the best place to look for suitable material for solving such problems?

Question

Computer networks

A Frame Relay network transmits data at 64 kbps. After 1 second, the throughput drops to 32 kbps. Construct a time diagram of the first 2 seconds of transmission if t391 =0.1 s, n391=1.5s when using SSU. Calculate the amount of useful and service information after 15 seconds.