Dell PowerConnect 54 Series, User Manual

Page: 383 / 416

Configuring Quality of Service
383
9
Configuring Quality of Service
This section provides information for defining and configuring Quality of Service (QoS) parameters. To
open the Click
Quality of Service in the tree view.
Quality of Service (QoS) provides the ability to implement QoS and priority queuing within a network.
QoS improves network traffic flow based on policies, frame counters and context.
An implementation example that requires QoS include 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 also user-definable. The table below details the VPT to
queue default settings:
Table 9-1. CoS to Queue Mapping Table Default values
CoS Value Forwarding Queue Values
0 q3
1 q1
2 q2
3 q4
4 q5
5 q6
6 q7
7 q8