Diffserv Model; Qos Techniques Overview; Applying Qos Techniques In A Network - H3C S5820X Series Configuration Manual

The IntServ model demands high storage and processing capabilities because it requires all nodes along
the transmission path to maintain resource state information for each flow. The model is suitable for
small-sized or edge networks, but not large-sized networks, for example, the core layer of the Internet,
where billions of flows are present.
NOTE:
For more information about RSVP, see the

DiffServ model

The differentiated service (DiffServ) model is a multiple-service model that can satisfy diverse QoS
requirements. Unlike IntServ, DiffServ does not require an application to signal the network to reserve
resources before sending data. DiffServ is easy to implement and extend.
All QoS techniques in this document are based on the DiffServ model.

QoS techniques overview

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

Applying QoS techniques in a network

Figure 3 Position of the QoS techniques in a network
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.
Figure 3, traffic classification, traffic shaping, traffic policing, congestion management, and
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