ZyXEL Communications AMG1302 User Manual

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AMG1302/AMG1202-TSeries User’s Guide
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Quality of Service (QoS)
10.1  Overview
Use the QoS screen to set up your AMG1302/AMG1202-TSeries 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 bandwidth. QoS allows the AMG1302/AMG1202-TSeries to 
group and prioritize application traffic and fine-tune network performance. 
Without QoS, all traffic data are 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 
applications such as video-on-demand.
The AMG1302/AMG1202-TSeries assigns each packet a priority and then queues the packet 
accordingly. Packets assigned with a high priority are processed more quickly than those with low 
priorities 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.
In the following figure, your Internet connection has an upstream transmission speed of 50 Mbps. 
You configure a classifier to assign the highest priority queue (6) to VoIP traffic from the LAN 
interface, so that voice traffic would not get delayed when there is network congestion. Traffic from 
the boss’s IP address (192.168.1.23 for example) is mapped to queue 5. Traffic that does not 
match these two classes are assigned priority queue based on the internal QoS mapping table on 
the AMG1302/AMG1202-TSeries.
Figure 59   
QoS Example
10.1.1  What You Can Do in the QoS Screens
• Use  the  General screen (
) to enable QoS on the AMG1302/AMG1202-
TSeries, and specify the type of scheduling.
50 Mbps
DSL
VoIP: Queue 6
Boss: Queue 5
IP=192.168.1.23