Chapter 10 Quality of Service (QoS)
VMG/XMG Series User’s Guide
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10.5  The QoS Classification Setup Screen
Use this screen to add, edit or delete QoS classifiers. A classifier groups traffic into data flows according 
to specific criteria such as the source address, destination address, source port number, destination port 
number or incoming interface. For example, you can configure a classifier to select traffic from the 
same protocol port (such as Telnet) to form a flow.
You can give different priorities to traffic that the Zyxel Device forwards through the WAN interface. Give 
high priority to voice and video to make them run more smoothly. Similarly, give low priority to many 
large file downloads so that they do not reduce the quality of other applications.
Click Network Setting > QoS > Classification Setup to open the following screen.
Figure 133   Network Setting > QoS > Classification Setup 
The following table describes the labels in this screen.
Buffer 
Management
This field displays Drop Tail (DT). Drop Tail (DT) is a simple queue management algorithm that 
allows the Zyxel Device buffer to accept as many packets as it can until it is full. Once the buffer 
is full, new packets that arrive are dropped until there is space in the buffer again (packets are 
transmitted out of it).
Rate Limit Specify the maximum transmission rate (in Kbps) allowed for traffic on this queue. If you enter 0 
here, this means there's no rate limit on this queue.
Cancel Click Cancel to exit this screen without saving.
OK Click OK to save your changes.
Table 69   Queue Setup: Add (continued)
LABEL DESCRIPTION
Table 70   Network Setting > QoS > Classification Setup
LABEL DESCRIPTION
Add New 
Classification
Click this to create a new classifier.
Order This is the index number of the entry. The classifiers are applied in order of their numbering.
Status This field displays whether the classifier is active or not. A yellow bulb signifies that this 
classifier is active. A gray bulb signifies that this classifier is not active.
Class Name This is the name of the classifier.
Classification 
Criteria
This shows criteria specified in this classifier, for example the interface from which traffic of 
this class should come and the source MAC address of traffic that matches this classifier.
DSCP Mark This is the DSCP number added to traffic of this classifier.
802.1P Mark This is the IEEE 802.1p priority level assigned to traffic of this classifier.
VLAN ID Tag This is the VLAN ID number assigned to traffic of this classifier.