What is used to avoid assigning entire addresses of a particular class to networks that didn't have that many hosts?

To avoid assigning entire addresses of a particular class to networks that didn't have that many hosts, subnetting is used. Subnetting allows network administrators to divide a larger network into smaller, more manageable sub-networks, or subnets. This helps optimize the use of IP address space and ensures that only the necessary number of addresses are allocated, preventing waste. By using variable-length subnet masking (VLSM), different subnets can have different sizes, further improving address utilization.