Q$4$: Host A needs to send a $7200$ byte file to Host B$.$ The largest packet Host A can send is $1200$ bytes, so Host A will send multiple packets to Host B$.$ The path from Host A to Host B has two links with rates $R_1=900kbps$ and $R_2=450kbps.$ Each link is $5km$ long and has a propagation speed $s=2\mathrm{.}5{10}^{8}mps.$

a$.$ Assuming no other network traffic, what is the throughput of the data transfer $($if you are unsure, go back to Chapter $1$ in the textbook$)?$

b$.$ Dividing the file size by the throughput, roughly how long will it take to transfer the file to Host $B?$

c$.$ Suppose the $3$rd packet arrives to the outbound queue of Host A$,$ waiting to be transmitted on to link $1.$ When it arrives, the $1$st packet is halfway done being transmitted into the link and packet $2$ is waiting to be transmitted. Packets are transmitted in order of arrival. What is the queuing delay for the $3$rd packet? It may be helpful to draw a picture of this situation to understand the analysis.