Suppose nodes A, B, C and D are connected on an 800 kbps link in a line A---B---C---D. The propagation delay between the neighboring nodes (A and B, B and C and C and D) is 5 ms. Assume nodes use CSMA/CD and exponential backoff is disabled. Consider the following cases and answer if they are possible or not. Explain your answer in 2-3 sentences and show calculations. Note that each of the following cases are independent (not occurring one after the other) and frame size is 1000 bytes. a. Assume that node A starts transmitting a frame at t=0ms. Now, node D wants to transmit a frame at t = 12ms. Will node D be able to start the transmission of the frame? Will there be a collision?

b. Assume that node A starts transmitting a frame at t=5ms. Node D starts transmitting a frame at t=18ms. Will there be a collision? If yes, who will (A or D) will detect the collision first? Why?

c. Assume that node A starts transmitting a frame to node B at t=5ms and node D starts transmitting a frame to node C at t=0ms. Can these two frames be received at their intended receivers without collision?