The congestion window size for TCP Reno varies as the following figure. Please answer the following questions:

1. The first TCP slow start phase in the figure start from Round __?__ to Round __?__.
2. When does the TCP sender detect 3 duplicate ACKs and cut down CWND size? In Round __?__
3. When does the TCP sender detect timeout and cut down CWND size? In Round __?__

14 12 10 ssthresh CWND (in segments) ssthresh 4 N 0 2 2 4 6 6 8 12 14 16 18 10 rounds