Consider a bidirectional link that uses Go-Back-N with N = 7. Suppose that all frames are one unit long and that they use a time-out value of 2. Assume the propagation is 0.5 unit and the processing time is negligible. Assume that ACK (Acknowledgment) timer is one unit long. Assuming stations A and B begin with their sequence numbers set to zero, show the pattern of transmissions and associated state transitions for the following sequences of events (Explain with diagram)

(a) Station A sends 6 frames in a row, starting at t = 0. All frames are received correctly. (Explain with diagram)

(b) Station A sends 6 frames in a row, starting at t = 0. All frames are received correctly, except frame 3 is lost. (Explain with diagram)

(c) Station A sends 6 frames in a row, starting at t = 0. Station B sends 6 frames in a row, starting at t =0.25. All frames are received correctly. (Explain with diagram)