This boolean switches on matching by the IP header's DSCP (Differentiated Services Code Point) field, the 6-bit QoS marking that indicates a packet's intended traffic class, letting a rule filter by declared QoS priority at the IP layer rather than the VLAN-tag PCP field used for Layer-2 priority. An admin uses DSCP matching to enforce that only appropriately privileged traffic is allowed to carry a high-priority marking, or to route/police traffic differently based on its declared class of service. For example, an admin might write a rule matching DSCP value 46 (commonly EF, used for voice) on an untrusted access port and deny it, preventing end-user devices from self-marking their traffic as voice-priority to jump the QoS queue.