Chapter 6. Congestion-Avoidance Tools
This chapter includes the following topics:
Random Early Detection
Weighted Random Early Detection
DSCP-Based Weighted Random Early Detection
Explicit congestion notification
Congestion-avoidance mechanisms, such as Weighted Random Early Detection (WRED), are complementary to (and dependent on) queuing algorithms. Queuing/scheduling algorithms manage the front of a queue, whereas congestion-avoidance mechanisms manage the tail of a queue.
Congestion-avoidance QoS tools are designed to handle TCP-based data traffic. TCP has built-in flow-control mechanisms that operate by increasing the transmission rates of traffic flows (even though bounded by buffers and window sizes) until packet loss occurs. At this point, TCP ...