James F. Kurose, Keith W. Ross

Problems

Computer Networks And The Internet

6

9780132856201

5

Review the car-caravan analogy in Section 1.4. Assume a propagation speed of 100 km/hour.

a. Suppose the caravan travels 150 km, beginning in front of one tollbooth,passing through a second tollbooth, and finishing just after a third tollbooth. What is the end-to-end delay?

b. Repeat (a), now assuming that there are eight cars in the caravan instead of ten.

a)

Suppose the caravan travels 150 km, beginning in front of one tollbooth, passing through a second tollbooth, and finishing just after a third tollbooth.

Assume a propagation speedof 100 km/hour.

Delay time=total distance/propagation speed

=150/100km/hr

=1.5 hrs

Time for taken by 3 tollbooths to reach 10 cars= 2*3=6 minutes.

So, end-to-end delay = 1hr 30 minutes + 6 minutes

= 1hr 36minutes.

b)

assuming that there are 8 cars in the caravan instead of 10.

Time for taken by 3 tollbooths to reach 8 cars= 96*3=288 minutes=4 minutes 48 seconds.

So, end-to-end delay = 1hr 30 minutes + 4 minutes 48 seconds

= 1hr 34 minutes 48 seconds