ZyXEL Communications NVG2053, Руководство пользователя

Страница: 131 / 200

NVG2053 User’s Guide
131
C
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 NVG2053 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 NVG2053 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
Use the General ( Section 11.2 on page 132 ) screen to enable or disable QoS, set
the
bandwidth,
and allow the NVG2053 to automatically assign priority to upstream
traffic according to the DSCP value. This screen also lets you add, edit or delete
QoS classes.