How many bits make up a standard IPv4 address?

A standard IPv4 address is composed of 32 bits. This structure allows for a total of approximately 4.3 billion unique addresses, as it is structured as four octets, each containing 8 bits. The bits are typically represented in decimal form as four numbers separated by dots, known as dotted-decimal notation (for example, 192.168.1.1). This addressing scheme is foundational to how devices communicate over IP networks, enabling precise identification of each device within a subnet.

The other options reflect different addressing schemes or versions—16 bits are associated with older standards such as IPv4 in certain contexts, 64 bits can be found in some configurations of IPv6, and 128 bits are characteristic of the standard IPv6 address itself, which allows for an even larger pool of IP addresses to accommodate the growing needs of internet-connected devices. Thus, the 32-bit designation for IPv4 addresses is essential for understanding network design and addressing in current internet protocols.