Let's now consider the general case of sending one packet from source to destination over a path consisting of $N$ links each of rate $R($thus$,$ there are $N-1$ routers between source and destination$).$ Applying the same logic as above, we see that the end$-$to$-$end delay is:

dend$-$to$-$end$=$NLR

You may now want to try to determine what the delay would be for $P$ packets sent over a series of $N$ links.

P$2.$ Equation $1\mathrm{.}1$ gives a formula for the end$-$to$-$end delay of sending one packet of length $L$ over $N$ links of transmission rate $R.$ Generalize this formula for sending $P$ such packets back$-$to$-$back over the $N$ links.