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Question

A system uses the Stop-and-Wait Protocol. If each packet carries 1000 bits of
data, how long does it take to send 1 million bits of data if the distance between the
sender and receiver is 5000 Km and the propagation speed is 2 x 108 m/s? Ignore transmission,
waiting, and processing delays. We assume no data or control frame is lost
or damaged.

Answer 1

Packet size = 10³ bits

Total data to be transmitted = 10⁶ bits

Therefore, number of packets to be transmitted = 10⁶ / 10³ = 1000

Propagation delay for one packet = Distance / Propagation speed = (5 * 10⁶) / (2*10⁸)  = 0.025 s

Propagation delay for one ACK = Distance / Propagation speed = (5 * 10⁶) / (2*10⁸)  = 0.025 s

Here, transmission delay is 0.

So, Total time to transmit one packet and receive its ACK = 2 * 0.025 = 0.05 s

Therefore, total time to transmit 1000 packets = 1000 * 0.05 = 50 s