Which of the following IPv4 address classes is used for multicast addressing?
2012
Which of the following IPv4 address classes is used for multicast addressing?
Answer: D. Class D — ConceptIn traditional classful IPv4 addressing, the leading bits of the first octet identify the address class and therefore its numerical range. Classes A,…
- A.
Class A
- B.
Class B
- C.
Class C
- D.
Class D
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Show answer & explanation
Correct answer: D
Concept
In traditional classful IPv4 addressing, the leading bits of the first octet identify the address class and therefore its numerical range.
Classes A, B, and C describe unicast network-and-host formats, while the 224.0.0.0/4 block is set aside for IPv4 multicast group addresses.
Application
Read the first-octet boundary of the multicast block: 224.0.0.0/4 spans first-octet values from 224 through 239.
The leading-bit pattern for this range is 1110, which is the classful identifier for Class D.
Therefore, an IPv4 multicast group address belongs to Class D in the traditional classful terminology.
Contrast and cross-check
Class A: leading bit 0; traditional first octet 1–126; unicast addressing.
Class B: leading bits 10; traditional first octet 128–191; unicast addressing.
Class C: leading bits 110; traditional first octet 192–223; unicast addressing.
Class D: leading bits 1110; first octet 224–239; the same range as 224.0.0.0/4 multicast addressing.
Hence, the IPv4 address class used for multicast addressing is Class D.