Question#$2$:

Consider the following situation, which involves four separate servers connecting to four different clients over four three$-$hop paths between servers and clients. The four pairings have a common intermediate hop with a transmission capacity of $R=300Mbps.$ The four links between the servers and the shared link have a transmission capacity of RS $=70Mbps.$ Each of the four links between the shared middle link and a client has a transmission capacity of $RC=100Mbps.$

a$)$ What is the maximum attainable end$-$to$-$end throughput $($in Mbps$)$ for each of four client$-$server pairs, assuming that the intermediate link capacity is shared fairly among all the pairs?

b$)$ Which link is the bottleneck link $(Rs,R,$ or $R)?$

c$)$ Assuming that the servers are sending at the maximum rate possible, what are the link utilizations for the server links $($RS$)?$

d$)$ Assuming that the servers are sending at the maximum rate possible, what are the link utilizations for the client links $($RC$)?$

e$)$ Assuming that the servers are sending at the maximum rate possible, what is the link utilizations for the shared link $(R?$

f$)$ Assume a file of $1$Gbits is being sent from one of the servers at one end of the connection to the client at the other end of the connection. What is the estimated time taken to send the file?

g$)$ Why is it not preferred for the Internet link at the network core to be the bottleneck link?