Summary

This Chapter introduces the reader to Layer 2 and 3 QoS technologies.

• Classification and Marking Specifies priorities for different groups of applications.

• Congestion Management Based on priorities, switches packets with various queuing mechanisms and applies shaping or policing.

• Congestion Avoidance By using congestion avoidance, packets are randomly dropped periodically based on class before congestion occurs. Signaling allocates bandwidth and QoS for traffic flows before sending the application traffic.