VLSM Planner
Subnetting
Overview
Variable-Length Subnet Masking allocates different sized blocks from a parent network. Sort host requirements largest first, include reserved addresses, round up to a power of two and align each block. Never overlap allocations or exceed the parent. This planner allocates ordinary LAN subnets, not /31 links.
Protocol stages
- 1Host requirements
- 2Largest first
- 3Power-of-two block
- 4Alignment
- 5Capacity check
Knowledge check
A LAN needs 50 usable hosts. What is the smallest ordinary subnet?
Educational model — not real hardware, traffic or official certification.