A. provide service internetworking
B. support transparency for Layer 2 frames
C. indicate destination as a connection identifier
D. map to the DLCI in service internetworking

A. Neither broadcast nor multicast traffic is ever flooded in VPLS.
B. Multicast traffic is flooded but broadcast traffic is not flooded in VPLS.
C. VPLS emulates an Ethernet switch， with each EMS being analogous to a VLAN.
D. Because U-PE devices act as IEEE 802.1 devices， the VPLS core must use STP.
E. When the provider experiences an outage， IP re-routing restores PW connectivity and MAC re-learning is needed.