Qos overview, Introduction to qos, Qos service models – H3C Technologies H3C WX3000E Series Wireless Switches User Manual
Page 19: Best-effort service model
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QoS overview
This chapter includes these sections:
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NOTE:
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The term "switch" or "device" in this chapter refers to the switching engine on a WX3000E
wired-wireless switch.
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The WX3000E series comprises WX3024E and WX3010E wired-wireless switches.
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The port numbers in this chapter are for illustration only.
Introduction to QoS
In data communications, Quality of Service (QoS) is the ability of a network to provide differentiated
service guarantees for diversified traffic in terms of bandwidth, delay, jitter, and drop rate.
Network resources are scarce. The contention for resources requires that QoS prioritize important traffic
flows over trivial ones. For example, in the case of fixed bandwidth, if a traffic flow gets more bandwidth,
the other traffic flows will get less bandwidth and may be affected. When making a QoS scheme, you
must consider the characteristics of various applications to balance the interests of diversified users and
to utilize network resources.
The following section describes some typical QoS service models and widely used, mature QoS
techniques.
QoS service models
This section covers three typical QoS service models:
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Best-effort service model
Best effort is a single-service model and also the simplest service model. In the best-effort service model,
the network does its best to deliver packets, but does not guarantee delay or reliability.
The best-effort service model is the default model in the Internet and applies to most network applications.
It uses the first in first out (FIFO) queuing mechanism.