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Dscp mapping – Dell PowerEdge VRTX User Manual

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441

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Guide\Plasma_UGQoS.fm

D E L L CO N F I D E N T I A L – P R E L I MI N A RY 4/ 1 8 /1 3 - F O R PR O O F O N LY

a

Single Policer — Create a policy that associates a class map with a

single policer in the Policy Table pages and the Class Mapping pages.

Within the policy, define the single policer.

b

Aggregate Policer — Create a QoS action for each flow. This action

sends all matching frames to the same policer (aggregate policer),

defined in the Aggregate Policer pages. Create a policy that associates

a class map with the aggregate policer in the Policy Table pages.

6 Bind the policy to an interface in the Policy Binding pages

.

DSCP Mapping

When a policer is assigned to a class map (flow), you can specify the action to

take when the amount of traffic in the flow(s) exceeds the QoS-specified

limits. The portion of the traffic that causes the flow to exceed its QoS limit

is referred to as out-of-profile packet

s

.

If the exceed action is Remark DSCP (as opposed to Drop), the switch

rewrites the original DSCP value of the out-of-profile IP packets to a new

value, based on the values entered in the DSCP Mapping page. The switch

uses the new values to assign resources and egress queues to these packets.

The switch physically replaces the original DSCP value in the out-of-profile

packets with the new DSCP value.
To use the Remark DSCP exceed action, set the DSCP Out value in the

DSCP Mapping page. Otherwise the action is null, because the DSCP value

in the packet is rewritten to the original DSCP value, set by factory default.
To set new DSCP values:

1 Click Quality of Service > QoS Advanced Mode > DSCP Mapping to

display the DSCP Mapping page.

2 If the Exceed Action is Out-of-Profile (in the

Policy Class Maps

page) or

Remark DSCP (in the

Aggregate Policy

page), the DSCP In values are

rewritten with the DSCP Out values. Set the DSCP Out values as

required.