Chapter 15 Quality of Service (QoS)
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 15.5 on page 235
15.1.3 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 these two classes are assigned priority queue based on the
internal QoS mapping table on the ZyXEL Device.
Figure 133 QoS Example
VoIP: Queue 6
Boss: Queue 5
IP=192.168.1.23
226
for advanced technical information on QoS.
DSL
50 Mbps
P-660HN-Fx User's Guide