Which two of these are characteristics of MPLS VPNs？ （）
- A Layer 3 MPLS VPNs can forward only IP packets
- B Layer 2 MPLS VPNs can forward any network protocol
- C MPL S label paths are automatically formed based on Layer 2 frames
- D Layer 3 MPLS VPNs can forward any network protocol based on Layer 2 frames
- E In Layer 2 MPLS VPNS， the service provider controls the customer Layer 3 policie