Which statement correctly compares IPv4 and IPv6 addressing?

Which statement correctly compares IPv4 and IPv6 addressing?

• A. IPv4 uses 32-bit addresses, IPv6 uses 128-bit addresses.
• B. IPv4 uses 16-bit addresses; IPv6 uses 128-bit.
• C. IPv4 addresses are decimal; IPv6 addresses are hexadecimal.
• D. Both use 128-bit addresses.

Answer: (A)

IPv4 and IPv6 differ most in the size of their addresses. An IPv4 address is 32 bits long, which is written as four decimal numbers separated by dots (for example, 192.168.0.1). An IPv6 address is 128 bits long, typically written as eight groups of four hexadecimal digits separated by colons (for example, 2001:0db8:85a3:0000:0000:8a2e:0370:7334). This exact difference—32-bit versus 128-bit—is what the statement is testing. So the correct comparison is that IPv4 uses 32-bit addresses and IPv6 uses 128-bit addresses. The other choices mix up the bit length (16-bit vs 32-bit) or the notation without reflecting the actual size difference, which is the fundamental point here.

IPv4 and IPv6 differ most in the size of their addresses. An IPv4 address is 32 bits long, which is written as four decimal numbers separated by dots (for example, 192.168.0.1). An IPv6 address is 128 bits long, typically written as eight groups of four hexadecimal digits separated by colons (for example, 2001:0db8:85a3:0000:0000:8a2e:0370:7334). This exact difference—32-bit versus 128-bit—is what the statement is testing.

So the correct comparison is that IPv4 uses 32-bit addresses and IPv6 uses 128-bit addresses. The other choices mix up the bit length (16-bit vs 32-bit) or the notation without reflecting the actual size difference, which is the fundamental point here.