Question: The congestion window size, after it passes the initial slow start state, follows a saw tooth pattern called _________________________________.

Answer:

• The congestion window size, after it passes the initial slow start state, follows a sawtooth pattern called the additive increase/multiplicative decrease (AIMD) algorithm.
• The AIMD algorithm is used in TCP congestion control to increase the sending rate of packets until congestion is detected. When there is no congestion, the congestion window size is increased additively by one maximum segment size (MSS) for every round-trip time (RTT) of the connection. However, when congestion is detected, the congestion window size is decreased multiplicatively by a factor of 2, which reduces the sending rate of packets.
• This sawtooth pattern of increasing and then decreasing the congestion window size is repeated over time, creating the AIMD algorithm. It allows TCP to quickly detect and respond to congestion in the network, while also maintaining a high sending rate when there is no congestion.