Additive Increase - TCP Congestion Sawtooth

After the threshold, the toy congestion window grows by one MSS per RTT.

highlighted = computed this step

Avoidance grows gently

After slow start reaches the threshold, this toy uses additive increase. Each non-loss RTT adds exactly 1 MSS to cwnd.

\text{cwnd}_{next}=\text{cwnd}+1

RTT 4 starts at cwnd 8 and ends at 9.

8+1=9

The next row repeats the same small increase: 9 becomes 10.

9+1=10

Additive increase is the gentle rising side of the sawtooth after the threshold.

\text{add one per RTT}