Question $11$

A client host sends a $W=800-$byte file to a server which is $L=1200km$ away over a $B=2\mathrm{.}5G\frac{b}{s}$ optical fibre network.

$($i$)$ Calculate the upper bound of the link efficiency $(L{E}_{UB})$ for this transmission assuming that the speed of light in optical fibre is $c=200,000k\frac{m}{s}.$

$($ii$)$ What would be the $L{E}_{UB}$ for a link with transmission speed $B=2\mathrm{.}5M\frac{b}{s}?$ Explain why the results for the calculated values of $L{E}_{UB}$ in parts $($i$)$ and $($ii$)$ are different.

$($iii$)$ Calculate the necessary size of the file $W$ which will allow to achieve a $50\%L{E}_{UB}$ for a link you considered in part $($i$).$