In computer networking, how many bits are contained in a standard IPv4 address used on the Internet?

Introduction / Context:
Internet Protocol version 4, commonly written as IPv4, is one of the core protocols that enable communication on the Internet. Understanding the size of an IPv4 address is fundamental for topics such as subnetting, address exhaustion, and the transition to IPv6. This question checks if you remember the basic length of an IPv4 address in bits.

Given Data / Assumptions:

- The question explicitly refers to IPv4, not IPv6.- We are asked about the number of bits in an IPv4 address.- Several possible bit lengths are offered as options, including powers of two and small values.

Concept / Approach:
An IPv4 address is traditionally written in dotted decimal form, such as 192.168.1.10, but internally it is a binary number. Each dotted decimal part represents 8 bits, also called an octet. There are four octets, so the total number of bits is 4 multiplied by 8. By converting this reasoning into a simple multiplication, we can find the total bit length and then match it with the correct option.

Step-by-Step Solution:
Step 1: Recall that an IPv4 address consists of four numerical fields separated by dots, for example A.B.C.D.Step 2: Each of these fields, or octets, can range from 0 to 255, which requires 8 bits to represent.Step 3: Compute the total number of bits as 4 * 8.Step 4: Perform the multiplication: 4 * 8 = 32 bits.Step 5: Match this result with the options. Option C states 32 bits.Step 6: Confirm that none of the other options match the known definition of IPv4 address length.

Verification / Alternative check:
Networking textbooks and standards documents describe IPv4 as a 32 bit address space. This is the basis for the total number of possible addresses, which is 2^32. Constraints and reserved ranges reduce the number of usable addresses, but the underlying bit length remains 32. By contrast, IPv6 uses 128 bit addresses, which are referenced in other contexts but not in this question.

Why Other Options Are Wrong:
Option A, 128 bits, corresponds to IPv6, not IPv4. Option B, 64 bits, and option D, 16 bits, do not match any standard IP version definition. Option E, 8 bits, would be far too small and could represent only 256 unique values, which is clearly insufficient for global addressing. Therefore these options are incorrect in the context of IPv4.

Common Pitfalls:
Some learners confuse IPv4 and IPv6 lengths, especially because IPv6 is often discussed alongside IPv4 in modern networking courses. Another pitfall is to think only in dotted decimal terms and forget that each octet is actually a group of 8 bits. Remembering that IPv4 uses four octets helps anchor the concept of 32 bit addresses in memory.

Final Answer:
A standard IPv4 address contains 32 bits.