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James F. Kurose, Keith W. Ross
Computer Networks And The Internet
Question:18 | ISBN:9780132856201 | Edition: 6


How long does it take a packet of length 1,000 bytes to propagate over a link of distance 2,500 km, propagation speed 2.5 *10^8 m/s, and transmission rate 2 Mbps? More generally, how long does it take a packet of length L to propagate over a link of distance d, propagation speed s, and transmission rate R bps? Does this delay depend on packet length? Does this delay depend on transmission rate?



Transmission delay = L/R

                               = 8 bits/byte * 1,000 bytes / 2,000,000 bps

                              = 4 ms

Propagation delay = d/s

                            = 2,500 / 2.5×105

                            = 10 ms

Therefore, the total time = 4ms + 10 ms = 14 ms

No, the delay depend on packet lenght is not true.

No,  the delay depend on transmission rate is not true.



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