$6\mathrm{.}1$

a$)$ Why does the FCFS queuing policy not guarantee fairness among packet flows traversing a router?

b$)$ Why do you think the internet adopted a feedback$-$based approach for resource allocation and congestion avoidance instead of a reservation$-$based system?

c$)$ How does the Slow Start mechanism in TCP improve average connection throughput compared to AIMD?

d$)$ Explain why the Fast Retransmit mechanism in TCP improves connection data rate and reduces overall congestion.