Free Cisco SPRI 300-510 Actual Exam Questions - Question 5 Discussion

Maybe C, since only 23 bits from the IP are mapped, not 24.

C, since it’s the low order 23 bits used after the fixed MAC prefix.

C. It’s definitely about IPv4, since the standard mapping takes the lower 23 bits of the multicast IP and maps them to the MAC address after the fixed 24-bit prefix. The other options mention “higher-order” or 24 bits, which doesn’t align with how IPv4 multicast MAC addresses are formed. So, 23 bits from the low order part of the IP address is what’s actually used here.

D imo, because the standard Ethernet multicast MAC addresses start with a fixed 24-bit prefix (01:00:5E) and then use the lower 23 bits of the IPv4 multicast address to complete the MAC. The question asks how many bits are used to make the conversion, so it’s really about those lower bits mapping, not the high-order ones. So, it's the lower 23 bits of the IP that get mapped onto the MAC’s lower 24 bits, but since the first 24 bits of the MAC are fixed, the actual variable part comes from those 23 bits—making D a better fit overall.

I think it’s actually B since the mapping uses 23 bits from the IP address. B

Probably C, it’s usually the low order bits for multicast.