ZyXEL Communications LTE5121, Руководство пользователя

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LTE-5121 User’s Guide
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H A P T E R
9
Quality of Service (QoS)
9.1 Overview
This chapter discusses the LTE Device’s QoS screens.
1
Use these screens to set up your LTE Device
to use QoS for traffic management.
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. QoS allows the LTE Device to group
and prioritize application traffic and fine-tune network performance.
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.
The LTE 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 Internet gaming, and those for which jitter alone is a problem such as Internet radio
or streaming video.
9.1.1 What You Can Do in this Chapter
• Use the General screen to enable QoS, set the bandwidth, and allow the LTE Device to
automatically assign priority to upstream traffic according to the IP precedence or packet length
(
Section 9.2 on page 104 ).
• Use the Queue Setup screen to configure QoS queue assignment ( Section 9.3 on page 105 ).
• Use the Class Setup screen to set up classifiers to sort traffic into different flows and assign
priority and define actions to be performed for a classified traffic flow ( Section 9.4 on page 107 ).
• Use the Monitor screen to view the LTE Device’s QoS-related packet statistics ( Section 9.5 on
page 112 ).
9.1.2 What You Need to Know
The following terms and concepts may help as you read this chapter.
QoS versus Cos
QoS is used to prioritize source-to-destination traffic flows. All packets in the same flow are given
the same priority. CoS (class of service) is a way of managing traffic in a network by grouping
1. At the time of writing the LTE Device does not apply the configuration in the QoS screens.