Which class of IPv4 addresses is designed for multicast?

• A. Class A
• B. Class B
• C. Class C
• D. Class D

Answer: (D)

Multicast in IPv4 uses a special portion of the address space designated for one-to-many delivery. The address space is divided into classes, with Class D reserved specifically for multicast. Class D covers 224.0.0.0 to 239.255.255.255 (leading bits 1110). This range is set aside so routers and hosts can subscribe to a group and receive the traffic intended for that group, instead of delivering to a single host. The other classes map to unicast addressing (Class A, Class B, Class C) or to experimental use (Class E), which is why the multicast-focused range belongs to Class D.