An operator wants to ensure that they can differentiate their traffic types for the purpose...

To differentiate traffic types for the purpose of prioritization in their Ethernet LAN and IP/MPLS backbone, an operator can use the following three fields:

Traffic Class (TC): This is a 3-bit field in the MPLS label that can be used to indicate the priority or class of service (CoS) of the packet. The TC field can be mapped to the DSCP field in the IP header or the PCP field in the Ethernet header. The TC field can be used by MPLS routers to apply different per-hop behaviors (PHBs) such as queuing, scheduling, and dropping policies to different traffic classes12.

DSCP: This is a 6-bit field in the IP header that can be used to mark packets according to the differentiated services (DiffServ) model. The DSCP field can indicate the per-hop behavior (PHB) that the packet should receive at each router along its path. The DSCP field can be mapped to the TC field in the MPLS label or the PCP field in the Ethernet header. The DSCP field can be used by IP routers to provide QoS for different traffic types34.

PCP: This is a 3-bit field in the Ethernet header that can be used to mark packets according to the IEEE 802.1Q standard. The PCP field can indicate the priority or class of service (CoS) of the packet on an Ethernet LAN. The PCP field can be mapped to the TC field in the MPLS label or the DSCP field in the IP header. The PCP field can be used by Ethernet switches to provide QoS for different traffic types56.

References: MPLS Traffic Engineering - DiffServ-Aware Traffic Engineering, MPLS Traffic Engineering - DiffServ-Aware Traffic Engineering Configuration Guide, Differentiated services - Wikipedia, DSCP and Precedence Values - Cisco, 802.1Q VLAN IDs and Ethernet Interface Types - Juniper Networks, Introduction to Virtual LANs (VLANs) and Tagging - Ubiquiti Support and Help Center