ZyXEL Communications P-870HW-51A V2, Руководство пользователя

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P-870HW-51a v2 User’s Guide
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H A P T E R
11
Quality of Service (QoS)
11.1 Overview
Quality of Service (QoS) refers to both a network’s ability to deliver data with minimum delay,
and the networking methods used to control the use of bandwidth. Without QoS, all traffic data
is equally likely to be dropped when the network is congested. This can cause a reduction in
network performance and make the network inadequate for time-critical application such as
video-on-demand.
Configure QoS on the ZyXEL Device to group and prioritize application traffic and fine-tune
network performance. Setting up QoS involves these steps:
1 Configure classifiers to sort traffic into different flows.
2
Assign priority and define actions to be performed for a classified traffic flow.
The ZyXEL Device assigns each packet a priority and then queues the packet accordingly.
Packets assigned a high priority are processed more quickly than those with low priority if
there is congestion, allowing time-sensitive applications to flow more smoothly. Time-
sensitive applications include both those that require a low level of latency (delay) and a low
level of jitter (variations in delay) such as Voice over IP (VoIP) or Internet gaming, and those
for which jitter alone is a problem such as Internet radio or streaming video.
This chapter contains information about configuring QoS and editing classifiers.
11.1.1 What You Can Do in this Chapter
• The General screen lets you lets you enable or disable QoS and set the default DSCP
value for incoming traffic does not match a class ( Section 11.3 on page 118 ).
• The Queue Setup screen lets you lets you configure QoS queue assignment ( Section 11.4
on page 119 ).
• The Class Setup screen lets you add, edit or delete QoS classifiers ( Section 11.5 on page
120 ).