Congestion Avoidance

• In computer networks, congestion avoidance is a technique used to stop the situation known as congestion collapse, in which a network gets overloaded and performance sharply declines. A network may become almost useless due to congestion collapse, which can result in a significant fall in throughput. By regulating the speed at which data is transmitted, congestion avoidance seeks to maintain the network's optimal functioning.

1. Explicit Congestion Notification (ECN)

• Using explicit congestion notification (ECN), routers can alert sending nodes to approaching congestion before the buffers fill up.

• The sending nodes are then able to modify their transmission rates appropriately.

2. Window-Based Congestion Control

• This method, which is frequently used to TCP (Transmission Control Protocol), entails modifying the size of the transmission window in response to network conditions.

• The sending node constantly modifies the window size to maximize the rate at which data is transmitted.

• The sending node constantly modifies the window size to maximize the rate at which data is transmitted.

3. Slow Start

• The sending node begins by sending a modest number of packets during the slow start phase of TCP congestion control.

• Gradually, the number of packets sent grows until congestion is identified.

4. Congestion Avoidance Algorithm

• Congestion avoidance mechanism kicks in when the network crosses a threshold (congestion window size).

• The goal of this method is to keep data transmission at a steady pace without creating congestion.

5. Random Early Detection (RED)

• Routing devices use RED, a proactive congestion avoidance strategy, to discard packets at random before the buffer fills up.

• Red does this to alert transmitting nodes to lower their transmission rates in advance of congestion.

6. Quality of Service (QoS)

• QoS systems use various factors, like packet type, application type, or user-defined regulations, to prioritize network traffic.

• Quality of Service (QoS) helps to reduce congestion and provide maximum performance for vital applications by giving priority to critical traffic.

7. Traffic Shaping and Policing

• Traffic policing enforces predetermined traffic policies by deleting or flagging packets that violate them, whereas traffic shaping controls the velocity of data transmission to prevent abrupt surges of traffic.

8. Feedback Mechanisms

• Certain congestion avoidance systems dynamically modify the transmission rate based on feedback received from the network, such as packet loss or delay.

• Through good adaptation to fluctuating levels of congestion, these techniques are able to monitor network conditions.

Conclusion

Avoiding congestion is essential to preserving the performance and stability of the network. Even in the face of fluctuating network conditions, network managers can guarantee dependable and effective data transmission by putting into place efficient congestion avoidance procedures and techniques.