VLSM Planner
Split a network into subnets of differing size. Enter the base network and the demand per subnet — the allocation appears immediately, largest first so that no gaps are left behind.
Notes
- Largest demand first. The allocation sorts itself in descending order. Only then does every block sit on its natural boundary and no unusable gaps appear.
- Two addresses are lost. The network and broadcast address cannot be used as hosts. That is why 100 hosts require a /25 with 126 usable addresses.
- The smallest block is a /30. Even for a point-to-point link with two hosts. A /31 under RFC 3021 would be leaner, but is deliberately not assigned automatically here.
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