Dell PowerConnect 5548 User Guide - Page 670

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 packets. 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. 670 Dell PowerConnect 55xx Systems User Guide