Configuring Out-of-Profile DSCP Mapping

When a policer is assigned to a class maps (flows), 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 Out of Profile DSCP, the switch remaps the original DSCP value of the out-of-profile IP packets with a new value based on the Out of Profile DSCP Mapping Table. The switch uses the new values to assign resources and the egress queues to these packets. The switch also physically replaces the original DSCP value in the out of profile packets with the new DSCP value.

To use the out-of-profile DSCP exceed action, remap the DSCP value in the Out Of Profile DSCP Mapping Table. Otherwise the action is null, because the DSCP value in the table remaps the packets to itself by factory default.

This feature changes the DSCP tags for incoming traffic switched between trusted QoS domains. Changing the DSCP values used in one domain, sets the priority of that type of traffic to the DSCP value used in the other domain to identify the same type of traffic.

These settings are active when the system is in the QoS basic mode, and once activated they are active globally.

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:

  1. Click Quality of Service > QoS Advanced Mode > Out of Profile DSCP Mapping. The Out of Profile DSCP Mapping page opens. This page enables setting the change-the-DSCP-value of traffic entering or leaving the switch.
  2. DSCP In displays the DSCP value of the incoming packet that needs to be re- marked to an alternative value.

  3. Select the DSCP Out value to where the incoming value is mapped.
  4. Click Apply. The Running Configuration file is updated with the new DSCP Mapping table.