Cisco 3560G 48TS Software Configuration Guide - Page 557

Chapter 28 Configuring QoS 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 28-12. Then 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 28-12 DSCP-Trusted State on a Port Bordering Another QoS Domain QoS Domain 1 QoS Domain 2 IP traffic 101235 Set interface to the DSCP-trusted state. Configure the DSCP-to-DSCP-mutation map. 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: Step 1 Step 2 Command configure terminal mls qos map dscp-mutation dscp-mutation-name in-dscp to out-dscp Step 3 interface interface-id Step 4 mls qos trust dscp Purpose Enter global configuration mode. 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. Specify the port to be trusted, and enter interface configuration mode. Valid interfaces include physical ports. Configure the ingress port as a DSCP-trusted port. By default, the port is not trusted. 78-16156-01 Catalyst 3560 Switch Software Configuration Guide 28-35