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Congestion Control

A mechanism used to prevent a network from becoming overloaded with too much traffic, which would lead to packet loss and delays.

Categorynetwork

Overview

While flow control protects the receiver, congestion control protects the network itself. It detects when the network is becoming saturated and slows down the transmission rate.

TCP Congestion Control Algorithms

  • Slow Start: Gradually increasing the transmission rate until congestion is detected.
  • Congestion Avoidance: Increasing the rate more slowly once a threshold is reached.
  • Fast Retransmit/Fast Recovery: Quickly responding to packet loss without dropping back to slow start.

Indicators of Congestion

  • Packet loss (detected by missing ACKs or timeouts).
  • Increased latency (Round Trip Time).

Related Terms

TCPFlow Control