ZyXEL Communications Prestige P-870HW-51a v2 - Manual (Page 129)

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
130 ).
• The Queue Setup screen lets you lets you configure QoS queue assignment
( Section 11.4 on page 131 ).
• The Class Setup screen lets you add, edit or delete QoS classifiers ( Section
11.5 on page 133 ).