The first four bits of a multicast IP address are fixed as 1110 and are mapped to the most significant 25 bits of a multicast MAC address. Among the last 28 bits of a multicast IP address, only 23…

The first four bits of a multicast IP address are fixed as 1110 and are mapped to the most significant 25 bits of a multicast MAC address. Among the last 28 bits of a multicast IP address, only 23 bits are mapped to a multicast MAC address, and information about the other 5 bits is lost. As a result, 32 multicast IP addresses are mapped to the same MAC address.