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 ...

Get End-to-End QoS Network Design now with the O’Reilly learning platform.

O’Reilly members experience live online training, plus books, videos, and digital content from nearly 200 publishers.