$(50$ pts$)$ Node A and $B$ are connected by a bi$-$directional optical link with $1M\frac{b}{s}$ bandwidth and $1000km$

distance in each direction: $($show your work$).$

There is no packet drops or queuing delays incurred. For the following, assume the speed of light in glass is

$2{10}^8\frac{m}{s}.$ Also, $1Mb$ is ${10}^6$bits. $($no need to reduce your answer$)$

Node A wants to send a $100-$bit packet to B$.$ How long does it take for the packet to arrive to B $($total time

required for the packet to arrive to $B)?$