Which IPv4 address class contains a total of 128 networks?

The class of IPv4 addresses that contains a total of 128 networks is Class A. Class A addresses are structured to support a large number of hosts per network, with the first octet ranging from 1 to 126. The remaining three octets (24 bits) allow for a vast number of hosts within each network. However, the key point here is the number of available networks.

In Class A, the leading bit is always 0, which provides a range of 128 possible network identifiers (from 0 to 127). But since 0.0.0.0 is reserved for the default network and 127.0.0.0 is used for loopback, this leaves us with 126 usable Class A networks.

Consequently, the class structure supports the categorization of networks based primarily on size and the number of hosts required, making Class A suitable for large organizations requiring numerous IP addresses while accommodating a vast number of devices within each network.

In contrast, Class B and Class C have different structures that allow for a different number of networks, with Class B having 16,384 networks and Class C having over 2 million networks. Class D is not used for traditional networking; it is reserved for multicast