Which QoS method must ISP A implement to achieve this?

ISP A provides L2VPN services to Company B through an MPLS network. Company B uses all available CoS values to classify and different traffic forwarding within all Company B sites.

ISP A uses the following CoS values to differentiate service classes for the VPN customer traffic

• MPLS EXP 0 for Bronze service class

• MPLS EXP 1 for Silver service class

• MPLS EXP 2 for Gold service class

• Remaining MPLS EXP values for ISP A internal use

ISP A’s policy is to forward VPN customer traffic based only on their Bronze, silver and Gold service classes.

Which QoS method must ISP A implement to achieve this?
A . Short-pipe Mode
B . Russian Doll Model
C . Pipe Mode
D . Uniform Mode
E . Maximum Allocation Model