A subnet architecture planner is a tool for designing hierarchical IP address management (IPAM) structures across multiple sites, regions, or business units. Unlike a basic subnet calculator, a planner lets you allocate a parent CIDR block and then subdivide it into child subnets with specific sizes — modeling how address space will be distributed across your actual infrastructure.

InfraHub's planner also supports reserved IP assignment tracking, letting you designate specific addresses for gateways, load balancers, or management interfaces.

You start with a top-level CIDR block (e.g., 10.0.0.0/8) and define sites or divisions. The planner recursively subdivides address space according to the prefix lengths you specify for each division. It performs live conflict detection to prevent overlapping assignments. The hierarchical view mirrors how enterprise IPAM tools like Infoblox or NetBox organize address space.

Enterprise network architects use the planner before implementing address management in tools like Infoblox or phpIPAM. Cloud architects design multi-region AWS VPC hierarchies with predictable CIDR patterns. System integrators plan address space for managed service customers across multiple sites. Network engineers document subnet allocation for compliance and change management processes.