Interactive end-of-chapter exercises


Supplement to Computer Networking: A Top Down Approach 8th Edition


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Computing end-end delay (transmission and propagation delay)

Consider the figure below, with three links, each with the specified transmission rate and link length.




Assume the length of a packet is 16000 bits. The speed of light propagation delay on each link is 3x10^8 m/sec

Round your answer to two decimals after leading zeros



Question List


1. What is the transmission delay of link 1?

2. What is the propogation delay of link 1?

3. What is the total delay of link 1?

4. What is the transmission delay of link 2?

5. What is the propogation delay of link 2?

6. What is the total delay of link 2?

7. What is the transmission delay of link 3?

8. What is the propogation delay of link 3?

9. What is the total delay of link 3?

10. What is the total delay?




Solution


Link 1 transmission delay = L/R = 16000 bits / 10 Mbps = 0.0016 seconds

Link 1 propagation delay = d/s = ()3 Km) * 1000 / 3*10^8 m/sec = 1.00E-5 seconds

Link 1 total delay = d_t + d_p = 0.0016 seconds + 1.00E-5 seconds = 0.0016 seconds

Link 2 transmission delay = L/R = 16000 bits / 1 Mbps = 0.016 seconds

Link 2 propagation delay = d/s = ()500 Km) * 1000 / 3*10^8 m/sec = 0.0017 seconds

Link 2 total delay = d_t + d_p = 0.016 seconds + 0.0017 seconds = 0.018 seconds

Link 3 transmission delay = L/R = 16000 bits / 100 Mbps = 0.00016 seconds

Link 3 propagation delay = d/s = ()1 Km) * 1000 / 3*10^8 m/sec = 3.33E-6 seconds

Link 3 total delay = d_t + d_p = 0.00016 seconds + 3.33E-6 seconds = 0.00016 seconds

The total delay = d_L1 + d_L2 + d_L3 = 0.0016 seconds + 0.018 seconds + 0.00016 seconds = 0.019 seconds



That's incorrect

That's correct

The answer was: 0.0016

Question 1 of 10

The answer was: 1.00E-5

Question 2 of 10

The answer was: 0.0016

Question 3 of 10

The answer was: 0.016

Question 4 of 10

The answer was: 0.0017

Question 5 of 10

The answer was: 0.018

Question 6 of 10

The answer was: 0.00016

Question 7 of 10

The answer was: 3.33E-6

Question 8 of 10

The answer was: 0.00016

Question 9 of 10

The answer was: 0.019

Question 10 of 10

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