Table of Contents
Advertisement
Figure 4 Placement of the QoS techniques in a network
As shown in
Figure
4, traffic classification, traffic shaping, traffic policing, congestion management,
and congestion avoidance mainly implement the following functions:
•
Traffic classification—Uses certain match criteria to assign packets with the same
characteristics to a class. Based on classes, you can provide differentiated services.
•
Traffic policing—Polices flows entering or leaving a device, and imposes penalties on traffic
flows that exceed the pre-set threshold to prevent aggressive use of network resources. You
can apply traffic policing to both incoming and outgoing traffic of a port.
•
Traffic shaping—Proactively adapts the output rate of traffic to the network resources
available on the downstream device to eliminate packet drops. Traffic shaping usually applies to
the outgoing traffic of a port.
•
Congestion management—Provides a resource scheduling policy to determine the packet
forwarding sequence when congestion occurs. Congestion management usually applies to the
outgoing traffic of a port.
•
Congestion avoidance—Monitors the network resource usage, and is usually applied to the
outgoing traffic of a port. When congestion worsens, congestion avoidance reduces the queue
length by dropping packets.
17
Advertisement
Table of Contents
