Defining Class Mapping - Cisco 500 Series Administration Manual

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For example: Assume that there are three levels of service: Silver, Gold, and
Platinum and the DSCP incoming values used to mark these levels are 10, 20, and
30 respectively. If this traffic is forwarded to another service provider that has the
same three levels of service, but uses DSCP values 16, 24, and 48, Out of Profile
DSCP Mapping changes the incoming values as they are mapped to the outgoing
values.
To map DSCP values:
Click Quality of Service > QoS Advanced Mode > Out of Profile DSCP Mapping.
This page enables setting the change-the-DSCP-value of traffic entering or
leaving the device.
DSCP In displays the DSCP value of the incoming packet that needs to be re-
marked to an alternative value.
Select the DSCP Out value to where the incoming value is mapped.
Click Apply. The Running Configuration file is updated with the new DSCP
Mapping table.
Select Restore Defaults to restore the factory CoS default setting for this
interface.

Defining Class Mapping

A Class Map defines a traffic flow with ACLs (Access Control Lists). A MAC ACL,
IP ACL, and IPv6 ACL can be combined into a class map. Class maps are
configured to match packet criteria on a match-all or match-any basis. They are
matched to packets on a first-fit basis, meaning that the action associated with the
first-matched class map is the action performed by the system. Packets that
matches the same class map are considered to belong to the same flow.
Defining class maps does not have any effect on QoS; it is an interim step, enabling
the class maps to be used later.
If more complex sets of rules are needed, several class maps can be grouped into
a super-group called a policy (see
The Class Mapping page shows the list of defined class maps and the ACLs
comprising each, and enables you to add/delete class maps.
Configuring a
Cisco 500 Series Stackable Managed Switch Administration Guide
Quality of Service
QoS Advanced Mode
Policy).