Qos Techniques Overview; Applying Qos Techniques In A Network - HP A5120 EI Series Configuration Manual

QoS techniques overview

The QoS techniques include traffic classification, traffic policing, traffic shaping, line rate, congestion
management, and congestion avoidance. The following section briefly introduces these QoS techniques.

Applying QoS techniques in a network

Figure 3 Position of the QoS techniques in a network
Traffic direction
As shown in
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 actively reduces the queue length
by dropping packets.
Traffic classification
Traffic policing
Traffic policing
Congestion management
Congestion avoidance
Traffic shaping
Traffic policing
Figure 3, traffic classification, traffic shaping, traffic policing, congestion management, and
WAN
Congestion management
Congestion avoidance
Traffic shaping
Traffic policing
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