Which CLI command configures a trust boundary for incoming traffic based on DSCP values?

The qos trust dscp command is configured within an interface context on an HPE ArubaOS-CX switch. This command establishes a trust boundary, instructing the switch to honor the Differentiated Services Code Point (DSCP) value present in the IP header of incoming packets. By trusting the DSCP marking, the switch uses this value to classify the traffic and assign it to the appropriate internal quality of service queue for prioritization. This ensures that upstream QoS policies are maintained as traffic traverses the switch.

B. apply trust-dscp: This is not a valid command syntax in ArubaOS-CX for establishing a QoS trust boundary. The apply keyword is typically used for policies, not trust settings.
C. traffic trust dscp: The traffic keyword is incorrect for this context. QoS trust settings are configured under the qos command hierarchy in the ArubaOS-CX command-line interface.
D. qos enforce dscp: The enforce keyword implies a policing or rate-limiting action. This is different from trust, which simply accepts and uses the existing QoS markings for classification. ---

1. HPE ArubaOS-CX 10.12 Quality of Service Guide, Page 19, Chapter 3: "Configuring QoS trust mode". The guide explicitly states, "To trust the DSCP value in the IP packet header, enter the command qos trust dscp."

2. HPE ArubaOS-CX 10.12 Command-Line Interface Guide, Page 2999, "Interface context commands". The command qos trust dscp is listed with the description: "Configures the QoS trust mode of the interface to dscp."