In standard IPv4 networking, an IP address is a binary number of how many bits in length?

Introduction / Context:
Internet Protocol version 4, commonly known as IPv4, is one of the core protocols of the internet. Every device that communicates over IPv4 is assigned an IP address. Understanding the size of this address in bits is a fundamental networking fact that is frequently tested in general knowledge and computer awareness exams.

Given Data / Assumptions:

• The question is specifically about IP addresses in the context of IPv4.
• The unit requested is bits, not bytes.
• The options list several possible bit lengths that are powers of two.

Concept / Approach:
An IPv4 address is defined to be 32 bits long. It is usually written in dotted decimal notation as four numbers separated by dots, for example 192.168.1.10, where each number represents 8 bits and is called an octet. Because there are four octets of 8 bits each, the total length is 4 * 8 = 32 bits. Longer 128 bit addresses are used in IPv6, not in IPv4, and 64 bit lengths are more typical for other identifiers.

Step-by-Step Solution:
Step 1: Recall that dotted decimal notation for IPv4 addresses uses four decimal numbers, each ranging from 0 to 255. Step 2: Recognise that a value from 0 to 255 can be represented by 8 bits, which is why each group is also called an octet. Step 3: Multiply the number of octets by the bits per octet: 4 * 8 = 32 bits total. Step 4: Compare this with the options and see that 32 bits is one of the choices. Step 5: Confirm that no other option matches the standard definition of an IPv4 address length.

Verification / Alternative check:
Networking textbooks and certification study guides all mention that IPv4 uses 32 bit addresses and IPv6 uses 128 bit addresses. Subnetting examples also show that the address and prefix lengths add up within a 32 bit field. Whenever you see subnet masks such as 255.255.255.0 or prefix notations like /24 or /16, they are all defined inside a fixed 32 bit address. This repeated use of 32 confirms the correct answer.

Why Other Options Are Wrong:
8 bits: This is wrong because a single octet is 8 bits, but an entire IPv4 address contains four octets, not just one.
16 bits: This is wrong because 16 bits would allow only a very small address space and does not match any standard IP version address size.
64 bits: This is wrong because 64 bit lengths are not used for IPv4 addresses. IPv6 addresses are 128 bits long, not 64 bits.

Common Pitfalls:
Learners sometimes mix up bits and bytes. A 32 bit address can also be described as 4 bytes, which appears in some exam questions. Another common confusion is between IPv4 and IPv6, with IPv6 using 128 bits. Remember that classic IPv4, with its familiar dotted decimal format, is always 32 bits long.

Final Answer:
An IPv4 IP address is a 32 bits long binary number.