What is the difference between assigning your QoS policy map using the frame-relay class <class name> on the subinterface and assigning the QoS policy map under the interface-dlci statement?
The frame-relay class will apply the QoS on all PVCs in that interface while the QoS under the interface-dlci statement will only apply the QoS for that PVC.
For instance, you have 3 PVCs pointing to one serial interface (101, 201 and 301) and only want to assign a CIR of 128kbps to DLCI 201. If you apply a frame-relay class under the serial interface, all PVCs will inherit the 128kbps CIR. If you only want DLCI 201, you must apply it under the interface-dlci.