You are tasked to design a QoS policy for a service provider so they can include it in the design of their MPLS core network. If the design must support an MPLS network with six classes, and CEs will be managed by the service provider, which QoS policy should be recommended?

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D. map DSCP bits into the Exp field DSCP (6 bits, 64 codepoints) provides granular per-hop classification that maps directly to the 3-bit MPLS EXP/TC field, which supports up to 8 classes - sufficient for the required six. Because the SP manages the CEs, ingress PE routers can be configured to rewrite DSCP values into EXP bits, enforcing the QoS policy end-to-end through the MPLS core without relying on untrusted customer markings.

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A. map IP CoS bits into the IP Precedence field CoS bits are an 802.1Q Layer 2 field and are stripped at Layer 3 boundaries, making them unreliable for marking traffic across an MPLS IP backbone.

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B. map flow-label bits into the Exp field The IPv6 flow-label field is not used for MPLS EXP/TC marking and has no defined mapping to MPLS QoS fields in standard SP QoS design.

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C. map IP precedence bits into the DSCP field Mapping IP Precedence to DSCP is an IP-layer remarking operation that does not populate the MPLS EXP field needed for QoS enforcement inside the MPLS core.

You are tasked to design a QoS policy for a service provider so they can include it in the design of their MPLS core network. If the design must support an MPLS network with six classes, and CEs will

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