a$)$ The equation for determining the download time for a peer$-$to$-$peer file sharing and client$/$server file sharing is given below.

Dp$2$p $>=$ max$($F$/$us $,$ F$/$dmin $,$ NF $/($us $+$i$=1$N$$ui$))$

Dcs$=$max$($ NF$/$us$,$ F$/$dmin $)$

Match the following terms to what they represent

i$)$ F$/$us $1)$ Time needed for server to upload one copy of the file

ii$)$ F$/$dmin $2)$ Time for cooperating peers $+$ server to upload a copy of the file to all peers

iii$)$ NF $/($us $+$i$=1$N$$ui$)3)$ Time for server to upload file to all clients

iv$)$ NF$/$us $4)$ Time for slowest peer to download one copy of the file

$($b$)$ True or False: assuming that the server participates in the peer to peer exchange $($as in the equation above$),$ peer to peer download will always be faster than or the same speed as client$/$server download. Explain your answer

$($c$)$ You are building a communication network based on RFC $1149"$IP over avian carrier". You attach two $128$GB flash drives to your pigeon. You can write data to the flash drive at the rate of $20$ MB$/$s and you can read data from the flash drive at the rate of $50$MB$/$s$.$ The flying speed of a pigeon is $80$km$/$h and pigeons do not need to stop for food or rest before reaching destination.

i$)$What is the total time needed for you to send and your friend who lives in Brazil $($Rio is $13600$ km from Adelaide$)$ to receive a $4109$ bit file of your favourite home movies? Solve for the number of seconds delay. Show your work.

ii$)$Under what conditions would IP over avian carrier have a lower propagation delay or transmission delay than using the Internet? Explain your answer.

$($d$)$ Give two reasons why iterative DNS queries are preferred to recursive DNS queries. Explain your answer.