You can use QoS in MPLS networks to prioritize certain packets, just as you would prioritize IP packets. In the case of IP, you set the precedence or DiffServ Codepoint (DSCP) bits in the IP header to prioritize the IP packet. In the case of MPLS, you prioritize the packet by setting the Experimental (EXP) bits to a value between 0 and 7. The MPLS payload is a frame instead of an IP packet in the case of AToM. Three possibilities exist for marking the EXP bits:
Statically configuring the setting of the EXP bits
Marking the EXP bits according to the IP precedence bits
Using information from the frame header to set the EXP bits
You can statically configure the EXP bits by using Modular QoS Command Line Interface (MQC) on the router. ...