Design of Congestion Prevention Algorithms in Computer Networks

Congestion is said to occur in the network when the resource demands exceed the capacity and packets are lost due to too much queuing in the network. A congestion avoidance scheme allows a network to operate in the region of low delay and high throughput. Such schemes prevent a network from entering the congested state. Congestion avoidance is a prevention mechanism while congestion control is a recovery mechanism. We compare the concept of congestion avoidance with that of flow control and congestion control. We model the network and the user policies for congestion avoidance as a feedback control system. The key components of a generic congestion avoidance scheme are: congestion detection, congestion feedback, feedback selector, signal filter, decision function, and in-crease/decrease algorithms. These components have been explained.