A Service Provider Sets Up LSP Among All the Edge

Multiple Choice

A service provider sets up LSP among all the edge routers in its network by using LDP. A user would like to maintain its DSCP marking across the service provider backbone. Mark the MPLS packets with the appropriate EXP values according to QoS policies. Which step should be taken to classify and queue packets on egress nodes on the basis of EXP marking?

A) disable penultimate hop popping
B) use MPLS network-wide QoS propagation
C) copy IP DSCP at the ingress into MPLS EXP
D) copy MPLS EXP at penultimate hop into DSCP