Hello,
1) "If there was no circuit switching ..." -> you mean if store-and-forward was used instead? This question is examined in the Store and forward exercise: it would be N*(dprop + dtrans1) + dtrans2 - you can see this in figure 8 if you ignore dproc.
Do you mean something else?
2) I sketched an explanation. In it, dprop = 0, so that it is easier to see the point.
1) "If there was no circuit switching ..." -> you mean if store-and-forward was used instead? This question is examined in the Store and forward exercise: it would be N*(dprop + dtrans1) + dtrans2 - you can see this in figure 8 if you ignore dproc.
Do you mean something else?
2) I sketched an explanation. In it, dprop = 0, so that it is easier to see the point.
![Expl](https://moodlearchive.epfl.ch/2021-2022/pluginfile.php/1828067/mod_forum/post/134826/PXL_20211111_140604395.jpg?time=1636639707779)
In the example, messages are sent in ascending order based on their size. The total duration is the same.
You "pay" to transmit A N times, and to transmit B, C, and D once each.
"and in the formula of the answer why is it that we multiply Dprop only N times?"
"and in the formula of the answer why is it that we multiply Dprop only N times?"
check figure 8 of the solutions. Only 1xdprop is added for every link.