Question

Q6. Total: 7 marks] Nodes A and B are accessing a shared medium with propagation delay of 300 bit times between them (i.e., propagation delay equals to the amount of time to transmit 300 bits onto the link). A and B each have a frame of 1,000 bits (including all headers and preambles) to send to each other. a) (3 marks] In the worst case, how many bits would A have sent out when it detects collision? Briefly show how you work out the answer. b) [4 marks] Suppose both A and B attempt to transmit at time t0. CSMA/CD protocol with back-off intervals of multiples of 512 bits is used. After the first collision, A draws K0 and B draws K-1 in the exponential back-off protocol. Ignore the jam signal and other unmentioned delays. At what bit time will A's packet be successfully received by B? Briefly show how you work out the answer. If the information given in the question is insufficient to derive the answer, explain why it is so

Answer 1