Question

Imagine that you have trained your Saint-Bernard, Tuco, to bring you 4 USB flash drives (instead of a flask of brandy). Each USB flash drive contains 32 GB. The dog can travel to your side at 18 km/hour.

a) Express the bit rate br that Tuco achieves as a function of the distance d that it must travel.

b) For what range of distances does Tuco have a higher data rate than a transmission line whose bit rate (exclusing overhead) is 150 Mbps?

c) How does your answer (in b.) change if Tuco’s speed doubles?

d) How does your answer (in b.) change if each USB Flash drive capacity doubles ?

e) Since we could reach high bit rates with Tuco, why don’t we use dogs to implement the physical layer?

Please explain and show all work, thanks.

Answer 1

e.) Dogs or any other living organism cannot be used to implement the transport layer even if it is possible to achieve high bit rates. There are several reasons for it. First of all, it would take much more work to train a dog up to this task. Secondly, it would not be safe or secure. Anybody in the middle could take the USB away from the dog, hence security cannot be guaranteed. Also, this method cannot be used for long distance communications. Hence dogs are not used to implement the physical layer.

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