ZyXEL Communications OLT-1308, User Manual, Page: 173 / 314

OLT-1308 Series User’s Guide
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H A P T E R
24
Priority Profile
This chapter describes how you can change packet priorities using the Priority Profile screen.
24.1 Priority Profile Overview
Quality of Service (QoS) refers to both a network’s ability to deliver data with minimum delay,
and the networking methods used to control the use of bandwidth. Without QoS, all traffic data
is 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 application such as
video-on-demand.
To ensure QoS on packets between layer 2 (L2) and layer 3 (L3) networks, you can configure
a priority profile to map TOS (L3) precedence bits to the COS (L2) value. Each COS value is
then mapped to the physical queue you specify in the
EPON Setup screen. The
The OLT determines the COS value of a packet using one of the following methods:
• Using the IEEE 802.1p priority level in the VLAN tag.
• Using the port’s default priority setting.
• Mapping the TOS bits.
In addition to configuring TOS-COS mappings, you can do the following to ensure QoS on the
network using a priority profile:
• Group traffic based on the Ethernet type, VLAN group or protocol number. Then assign a
VLAN priority and queue to the classified traffic.
• Associate a priority profile to a service profile.
24.2 Configuring a Priority Profile
Click Advanced Application > ( EPON Advance > ) Priority Profile to display the
configuration screen. Use this screen to change the precedence bits (TOS-COS mappings) and
VLAN priority and assign specified packets to queues. Once you have configured a priority
profile, associate it to a service profile to apply to an ONU.