Which prefix denotes IPv4 multicast addresses?

Which prefix denotes IPv4 multicast addresses?

• A. IPv4: 224.0.0.0/4
• B. IPv6: ff00::/8
• C. IPv6: fe80::/10
• D. IPv4: 255.255.255.0/24

Answer: (A)

Multicast in IPv4 is defined by a specific address block. The range 224.0.0.0/4 covers all IPv4 multicast addresses, from 224.0.0.0 to 239.255.255.255, with /4 indicating that the top four bits are 1110. This prefix is what signals that a packet is intended to be delivered to multiple hosts that join the multicast group, rather than to a single destination. The other options belong to different contexts: ff00::/8 is an IPv6 multicast prefix, not IPv4; fe80::/10 is an IPv6 link-local unicast range; and 255.255.255.0/24 is a subnet mask, not a multicast address range.

Multicast in IPv4 is defined by a specific address block. The range 224.0.0.0/4 covers all IPv4 multicast addresses, from 224.0.0.0 to 239.255.255.255, with /4 indicating that the top four bits are 1110. This prefix is what signals that a packet is intended to be delivered to multiple hosts that join the multicast group, rather than to a single destination.

The other options belong to different contexts: ff00::/8 is an IPv6 multicast prefix, not IPv4; fe80::/10 is an IPv6 link-local unicast range; and 255.255.255.0/24 is a subnet mask, not a multicast address range.