Obligatory problem for all students to solve. Consider a packet of length L that begins

at end system A and travels over three links to a destination end system B$.$ These three

links are connected by two packet switches. Let di$,$ si$,$ and Ri denote the length,

propagation speed, and the transmission rate of link i$,$ for i $=1,2,3.$ The packet switch

delays each packet by dproc. Assuming no queuing delays, in terms of di$,$ si$,$ Ri$,($i $=1,2,$

$3),$ and L$,$ what is the total end$-$to$-$end delay for the packet? Suppose now the packet is

$1,500$ bytes, the propagation speed on all three links is $2\mathrm{.}5108$ m$/$s$,$ the transmission

rates of all three links are $2\mathrm{.}5$ Mbps$,$ the packet switch processing delay is $3$ msec, the

length of the first link is $5,000$ km$,$ the length of the second link is $4,000$ km$,$ and the

length of the last link is $1,000$ km$.$ For these values, what is the end$-$to$-$end delay?

$($textbook Problem $10).$