ZyXEL Communications Corporation 5VZ-A2011 ユーザーズマニュアル

 Chapter 16 Quality of Service (QoS)

CellPipe 7130 RG User’s Guide

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 similar types of traffic together and treating each type as 
a class. You can use CoS to give different priorities to different packet types. 

CoS technologies include IEEE 802.1p layer 2 tagging and DiffServ (Differentiated 
Services or DS). IEEE 802.1p tagging makes use of three bits in the packet 
header, while DiffServ is a new protocol and defines a new DS field, which replaces 
the eight-bit ToS (Type of Service) field in the IP header. 

In a QoS class, you can configure whether to add or change the DSCP (DiffServ 
Code Point) value, IEEE 802.1p priority level and VLAN ID number in a matched 
packet. When the packet passes through a compatible network, the networking 
device, such as a backbone switch, can provide specific treatment or service 
based on the tag or marker.

Click Advanced Setup > Quality of Service to open the screen as shown next. 

Use this screen to enable or disable QoS and set the upstream bandwidth. See 

 for more information.

Figure 87   QoS General