Which of the following statement is incorrect regarding efficiency(η) in STOP and WAIT ARQ protocol ?
(A) Efficiency(η) ∝ 1 / distance between sender and receiver
(B) Efficiency(η) ∝ Bandwidth
(C) Efficiency(η) ∝ transmission speed
(D) Efficiency(η) ∝ length of the data packet


Answer: (B)

Explanation: Since, efficiency of stop and wait ARQ has,

Efficiency(η) = 1 / (1 + (2 * propagation delay / transmission delay)) 

Where,

Propagation delay  = distance / speed = d/v
Transmission delay = Bandwidth / packet length = L/B 

Therefore,

Efficiency(η) = 1 / (1 + (2 * (d/v) / (L/B)))
Efficiency(η) = 1 / (1 + (2 * (d*B/v*L)) 

So,

Efficiency(η) ∝ 1 / Bandwidth 

So, option (B) is correct.

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