ZyXEL P-660HW-T1 v3 User Guide - Page 254

What You Need to Know About QoS, QoS Class Setup Example

Page 254 highlights

Chapter 16 Quality of Service (QoS) 16.1.2 What You Need to Know About QoS QoS versus Cos QoS is used to prioritize source-to-destination traffic flows. All packets in the same flow are given the same priority. Class of Service (CoS) 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 Differentiated Services (DiffServ 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 Type of Service (ToS) field in the IP header. Tagging and Marking In a QoS class, you can configure whether to add or change the DiffServ Code Point (DSCP) 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. Finding Out More See Section 16.5 on page 266 for advanced technical information on QoS. 16.1.3 QoS Class Setup Example 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 254 P-660HW-Tx v3 Series User's Guide

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Chapter 16 Quality of Service (QoS)
P-660HW-Tx v3 Series User’s Guide
254
16.1.2
What You Need to Know About QoS
QoS versus Cos
QoS is used to prioritize source-to-destination traffic flows. All packets in the same
flow are given the same priority. Class of Service (CoS) 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 Differentiated Services
(DiffServ 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 Type of Service (ToS) field in the IP header.
Tagging and Marking
In a QoS class, you can configure whether to add or change the DiffServ Code
Point (DSCP) 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.
Finding Out More
See
Section 16.5 on page 266
for advanced technical information on QoS.
16.1.3
QoS Class Setup Example
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