ZyXEL Communications P-3202HN-Ba, Руководство пользователя

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IAD User’s Guide
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H A P T E R
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Quality of Service (QoS)
14.1 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 IAD 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 IAD 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.
14.1.1 What You Can Do in this Chapter
• The General screen lets you lets you enable or disable QoS and set the
upstream bandwidth
( Section 14.2 on page 164 ).
• The Class Setup screen lets you add, edit or delete QoS classifiers ( Section
14.3 on page 166 ).
• The Monitor screen lets you view the IAD's QoS-related packet statistics
( Section 14.4 on page 175 ).