QUESTION $12$QUESTION $13$

$3\mathrm{.}7-2$b Phases of TCP congestion control $($b$).$ Consider again the figure above $($question $3\mathrm{.}7-2$a$)$ showing the evolution of TCP$\text{'}$s

congestion window size. In this figure, during which of the following intervals of time is TCP performing congestion avoidance?

$3\mathrm{.}7-2$a Phases of TCP congestion control $($a$).$ Consider the figure below, which plots the evolution of TCP$\text{'}$s congestion window at the

beginning of each time unit $($where the unit of time is equal to the RTT$)$; see Figure $3\mathrm{.}53$ in the text. In the abstract model for this

problem, TCP sends a "flight" of packets of size cwnd at the beginning of each time unit. The result of sending that flight of packets is

that either $($i$)$ all packets are ACKed at the end of the time unit, $($ii$)$ there is a timeout for the first packet, or $($iii$)$ there is a triple duplicate

ACK for the first packet.

During which of the following intervals of time is TCP performing slow start?