Which of the following can be the cause of the fault?

Two PPPoE users, the VLAN numbers respectively are 10 and 12. Use HT880 Modem, built-in PPPoE dial-up, user name belongs to the same domain. Both modems can successfully perform PPPoE dialing, but only one user can be online at the same time.

Which of the following can be the cause of the fault?
A . Domain configuration restrictions on BRAS cause errors.
B . Other resource limitations such as the IP address pool on the BRAS result in errors.
C . The two PPPoE users have the same MAC address.
D . Above are possible

Answer: D