Configuring Quality Of Service - Dell PowerConnect 2808 User Manual

Configuring Quality of Service

This section provides information for defining and configuring Quality of Service (QoS) parameters.
To open the Quality of Service page, click Quality of Service in the tree view.
An implementation example that requires QoS includes certain types of traffic such as Voice, Video
and real-time traffic which can be assigned a high priority queue, while other traffic can be assigned
a lower priority queue. The result is an improved traffic flow for traffic with high demand.
QoS is defined by:
• Classification — Specifies which packet fields are matched to specific values. All packets
matching the user-defined specifications are classified together.
• Action — Defines traffic management where packets being forwarded are based on packet
information, and packet field values such as VLAN priority (VPT) and DSCP (DiffServ Code
Point).
VPT Tag Classification Information
VLAN Priority Tags are used to classify the packets by mapping packets to one of the output queues.
VLAN Priority Tag to queue assignments are user-definable. The table below details the VPT to
queue default settings:
Table 9-1. CoS to Queue Mapping Table Default values
CoS Value
0
1
2
3
4
5
6
7
Packets arriving untagged are assigned a default VPT that is set on a per port basis. The assigned
VPT is used to map the packet to the output queue and as the egress VPT.
Forwarding Queue Values
q
q1
q1
q
q
q
q
q
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