How many bits of the MAC address space is available for mapping IP multicast addresses?
How many bits of the MAC address space is available for mapping IP multicast addresses?
In the context of mapping IP multicast addresses, 23 bits of the MAC address space are available. Specifically, the leftmost 25 bits are predetermined with 0x01005E for IPv4 multicast and the 25th bit is always 0, leaving the remaining rightmost 23 bits for the mapping.
Correct is D. The rightmost 23 bits of MAC address are mapped to the rightmost 23 bits of a multicast IPv4 address: https://support.huawei.com/enterprise/ru/doc/EDOC1000141881/d30cdf7f/multicast-mac-address
As defined by the IANA, the leftmost 24 bits of an IPv4 multicast MAC address are 0x01005E, the 25th bit is 0, and the rightmost 23 bits are mapped to the rightmost 23 bits of a multicast IPv4 address,