Slow-Start Threshold (ssthresh)

• Need a way to determine whether the TCP should do slow-start or congestion avoidance

• New variable (ssthresh):

  • if cwnd <= ssthresh, do slow-start
  • if cwnd > ssthresh, do congestion avoidance

• ssthresh is initialized to a large value, after a congestion signal, cwnd is divided in half, and ssthresh is set to cwnd

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