Which statement about operating frame MPLS over an ATM PVC is true?

A.
LDP sessions are established over a reserved PVC.

B.
The attached ATM switch is aware of the MPLS traffic.

C.
A TDP or LDP neighborship is established between the two PVC endpoint routers.

D.
Switching is performed based on the VPI/VCI value in the ATM header established by LDP.

Explanation:

In certain circumstances, such as during a transition to a full IP=ATM MPLS environment, or if transit ATM switches do not support MPLS, it might be desirable to run MPLS in Frame-mode across ATM PVCs. This is perfectly valid configuration although it suffers from the same scaling issues (due to the high number of VCs) as running IP over ATM in an overlay mode.