Configuring The Dscp Trust State On A Port Bordering Another Qos Domain - Cisco Catalyst 3550 series Software Configuration Manual

Configuring Standard QoS

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 as shown
in Figure
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 29-10 DSCP-Trusted State on a Port Bordering Another QoS Domain
QoS Domain 1
3550-12T switch
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:
Command
Step 1
configure terminal
Step 2
mls qos
Step 3 mls qos map dscp-mutation
dscp-mutation-name in-dscp to out-dscp
Step 4
interface interface-id
Step 5 mls qos trust dscp
Catalyst 3550 Multilayer Switch Software Configuration Guide
29-34
29-10. Then the receiving port accepts the DSCP-trusted value and avoids the classification
Gigabit
Ethernet
IP traffic
0/3
Catalyst
Set interface to the DSCP-trusted state.
Configure the DSCP-to-DSCP-mutation map.
QoS Domain 2
Gigabit
Ethernet
0/3
Catalyst
3550-12T switch
Purpose
Enter global configuration mode.
Enable QoS on the switch.
Modify the DSCP-to-DSCP-mutation map.
The default DSCP-to-DSCP-mutation map is a null map, which maps
an incoming DSCP value to the same DSCP value.
• For dscp-mutation-name, enter the mutation map name. You can
create more than one map by specifying a new name.
For in-dscp, enter up to eight DSCP values separated by spaces.
•
Then enter the to keyword.
For out-dscp, enter a single DSCP value.
•
The DSCP range is 0 to 63.
Enter interface configuration mode, and specify the interface to be
trusted.
Valid interfaces include physical interfaces.
Configure the ingress port as a DSCP-trusted port.
Chapter 29 Configuring QoS
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