Cisco Catalyst 2960 Series, Configuration Manual

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Configuring the DSCP Trust State on a Port Bordering Another QoS Domain
If you are administering two separate QoS domains between which you want to implement QoS features for
IP traffic, you can configure the switch ports bordering the domains to a DSCP-trusted state. The receiving
port accepts the DSCP-trusted value and avoids the classification stage of QoS. If the two domains use different
DSCP values, you can configure the DSCP-to-DSCP-mutation map to translate a set of DSCP values to match
the definition in the other domain.
Figure 63: DSCP-Trusted State on a Port Bordering Another QoS Domain
Beginning in privileged EXEC mode, follow these steps to configure the DSCP-trusted state on a port and
modify the DSCP-to-DSCP-mutation map. To ensure a consistent mapping strategy across both QoS domains,
you must perform this procedure on the ports in both domains.
SUMMARY STEPS
1.
configure terminal
2. mls qos map dscp-mutation dscp-mutation-name in-dscp to out-dscp
3. interface interface-id
4.
mls qos trust dscp
5. mls qos dscp-mutation dscp-mutation-name
6.
end
7.
show mls qos maps dscp-mutation
8. copy running-config startup-config
Consolidated Platform Configuration Guide, Cisco IOS Release 15.2(4)E (Catalyst 2960-X Switches)
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How to Configure QoS