To meet specific business requirements, QoS-marked traffic must be sent over a dedicated link. Which technology fulfills this requirement?

MPLS provides label-switched forwarding and traffic engineering but does not natively steer traffic based on existing QoS markings to a dedicated local link.

Q-in-Q tunneling is a Layer 2 VLAN stacking technology used to extend customer VLANs across provider networks and has no mechanism to route based on QoS markings.

Policy-based routing uses route maps applied to an interface to match traffic characteristics - including DSCP or IP precedence QoS markings - and set the next-hop or outgoing interface regardless of the normal routing table. This allows an administrator to direct all QoS-marked traffic over a specific dedicated link to meet business SLA requirements. No other listed technology provides per-policy, mark-based forwarding to a designated physical path.

Traffic policing limits the rate of traffic flows by dropping or remarking excess packets but does not control which physical link that traffic traverses.