"Computer network is a set of computers and hardware components linked together to communicate with each other. Congestion in networks occurs when at any node there is more data traffic than the outgoing link capacity. Effects of congestion are packet delay, packet drop, reduced system throughput and degraded quality of service. TCP (Transmission Control Protocol) packet drops can be used for congestion notification when source and destination nodes have ECN (Explicit Congestion Notification) negotiated. Congestion avoidance techniques monitor network traffic load to anticipate and avoid congestion."