Consider the following network with given line speeds and lengths:

Assume the speed of light is 2108 m/s, and that the processing and queuing delays are negligible. Node A sends a 1500-byte frame to node C through node B. Suppose Node A starts sending the first bit of the frame at t=0. Answer the following questions:

a. At what time (t=?) node B receives the frame in full (i.e. the last bit)? (5 marks)

b. After node B receives the frame in full, then it will start sending the frame to node C. Determine the time (t=?) when node C receives the frame in full. (5 marks)

c. Suppose at this time node C sends a small acknowledgment back to node A. The transmission time for the acknowledgment is negligible. Calculate at what times (t=?) the acknowledgment arrives at nodes B and A. (10 marks)

d. Assume after sending its frame, node A wait for the acknowledgment back from node C before sending the next frame. What is the average throughput (number of transmitted bits per second) of the data flow from node A to node C? (10 marks)