Hello Kali,
on the CE router you can perform different QoS actions like DSCP/TOS byte marking of input/output packets and you can shape you output traffic in order to comply with your per site specifications.
The PE router can be configured to accept your DSCP/TOS marking (for conforming packets) and to propagate it in the MPLS frames (EXP bits in MPLS labels) and can leave your DSCP settings unchanged even if it needs to use a different EXP settings on the MPLS header.
It requires cooperation between you and your provider but some work can be done.
The CE router cannot directly influence the EXP bits setting on the MPLS frames.
hope to help
Best Regards
Giuseppe
