my solution:
total packets = 60000 / 1000 = 60
The packets will be transmitted 3 times, at A, R1 and R2. They’ll have propagation delay on 3 links A – R1, R1 – R2 and R2 – B.
Also, 1st packet will take full time from A to B and rest 59 packets will follow in a pipeline.
Transmission time = 1 ms, propagation delay = 10 ms (given)
Therefore, total time = 1 * (3 * 1 + 3 * 10) ms + 59 * (3 * 10) ms = 623 ms
answer key’s solution:
Why did they count transmission delay for 59 packets? Shouldn’t it be propagation delay?