Computer Networks · M2 · mocks

Q1A · Carrier sensing and collisions

M2 mock A

Q1(a)+Q1(b) compulsory; choose any two of Q2/Q3/Q4 · 10 marks attempted

Question. Why does carrier sensing reduce but not eliminate collisions? [2 practice marks]

Answer

Carrier sensing observes the local medium. Because signals have nonzero propagation delay, another station’s new transmission may not yet be detectable. Both stations can then start and their transmissions overlap.