TCP Congestion Control: Slow Start

In this lesson, we're going to look at the slow start algorithm.

How Slow Start Works

The objective of TCP slow-start is to quickly reach an acceptable value for the congestion window.

During slow-start:

  1. The congestion window is doubled every round-trip time.
  2. The slow-start algorithm uses an additional variable in the TCB to maintain the slow-start threshold.
    • The slow-start threshold is an estimation of the last value of the congestion window that did not cause congestion.
    • It is initialized at the sending window and is updated after each congestion event.

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