Which two design concerns must be addressed when designing a multicast implementation？（）

A、only the low-order 23 bits of the MAC address are used to map IP addresses

B、only the low-order 24 bits of the MAC address are used to map IP addresses

C、only the high-order 23 bits of the MAC address are used to map IP addresses

D、only the low-order 23 bits of the IP address are used to map MAC addresses

E、the 0x01004f MAC address prefix is used for mapping IP addresses to MAC addresses

F、the 0x01005e MAC address prefix is used for mapping IP addresses to MAC addresses