In an IPv4 address, what does an octet represent?

• A. A 16-bit block
• B. An 8-bit value
• C. A 32-bit value
• D. A 4-bit nibble

Answer: (B)

An octet represents 8 bits in an IPv4 address. An IPv4 address is 32 bits long, written as four octets separated by dots, like 192.168.0.1. Each octet stores one 8-bit value, which can range from 0 to 255 in decimal. Since 8 bits can represent 2^8 = 256 values, the maximum for an octet is 255. The term octet emphasizes that each part of the address is a chunk of eight bits, and the whole address is four of these, totaling 32 bits. A 16-bit block would be two octets, a 32-bit value would be the entire address, and a 4-bit nibble is only half a byte.