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Assume TCP congestion control uses all the following algorithms covered : slow start (SS), congestion avoidance (CA), fast retransmit and fast recovery, and retransmission upon timeout. Right after fast retransmit/fast recovery phase, if ssthresh equals to cwnd, use the slow start algorithm. The congestion control algorithm works together with selective repeat (SR). - The receiver acknowledges every segment and uses TCP cumulative ACK (i.e., ACK = (largest sequence received in order at the receiver +1) ). Besides, the sender always has data available for transmission. - Initially ssthresh at the sender is set to 4, and cwnd as 1. Assume cwnd and ssthresh are measured in segments, and the transmission time for each segment is negligible. Retransmission timeout (RTO) is initially set to 500 ms at the sender and is unchanged during the connection lifetime. The RTT is 100ms for all transmissions. - The connection starts to transmit data at time t=0, and the initial sequence number starts from 1 . Segment with sequence number 9 is lost once. No other segments are lost. - When ssthresh equals to cwnd, we use slow start, not congestion avoidance. When does the sender receive the ACK for the segment with the sequence number 15 ? Which algorithms will be used upon receiving ACK for the segments with the sequence number 15 and 16? Show your diagram