QoS techniques overview
The QoS techniques include the following features:
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Traffic classification.
Traffic policing.
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Traffic shaping.
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Rate limit.
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Congestion management.
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Congestion avoidance.
The following section briefly introduces these QoS techniques.
All QoS techniques in this document are based on the DiffServ model.
Deploying QoS in a network
Figure 2 Position of the QoS techniques in a network
As shown in
congestion avoidance mainly implement the following features:
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Traffic classification—Uses match criteria to assign packets with the same characteristics to a traffic
class. Based on traffic classes, you can provide differentiated services.
Traffic policing—Polices flows and imposes penalties to prevent aggressive use of network resources.
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You can apply traffic policing to both incoming and outgoing traffic of a port.
Traffic shaping—Adapts the output rate of traffic to the network resources available on the
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downstream device to eliminate packet drops. Traffic shaping usually applies to the outgoing traffic
of a port.
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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.
Figure
2, traffic classification, traffic shaping, traffic policing, congestion management, and
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