Subnetting (Dividing)
Subnetting is the process of splitting a single large network into multiple smaller, logically isolated subnets. This is primarily done to reduce broadcast domains, segment traffic for security, and manage IP exhaustion locally.
Supernetting (Aggregating)
Supernetting (also known as Route Aggregation or CIDR Blocks) is the reverse process. It aggregates multiple contiguous smaller networks into a single larger routing entry with a shorter prefix (e.g., combining four `/24` networks into a `/22` network).
Requirements for Supernetting
For multiple networks to be combined into a supernet, they must meet two conditions:
1. **Contiguous**: The networks must be next to each other in address space.
2. **Power of Two**: The count of networks must be a power of two (e.g., 2, 4, 8, 16).
3. **Boundary Aligned**: The first subnet must start on a boundary address divisible by the total block size.