Subnet Math and IP Planning with AI
Lesson 5 of 10
The Scenario
You are designing the IP addressing scheme for a new branch office with 12 VLANs of varying sizes. You need to allocate from a /22 block efficiently. Doing VLSM by hand on a whiteboard is tedious and error-prone.
The Prompt
I have the network 172.16.0.0/22 to allocate for a branch office. Design a VLSM scheme for these VLANs:
- VLAN 10 (Management): 5 hosts
- VLAN 20 (Servers): 25 hosts
- VLAN 30 (Engineering): 100 hosts
- VLAN 40 (Sales): 50 hosts
- VLAN 50 (Guest WiFi): 30 hosts
- VLAN 60 (IoT/Printers): 15 hosts
- VLAN 70 (VoIP): 60 hosts
- VLAN 80 (Security Cameras): 20 hosts
- VLAN 100 (WAN Link 1): 2 hosts (/30)
- VLAN 101 (WAN Link 2): 2 hosts (/30)
- VLAN 102 (WAN Link 3): 2 hosts (/30)
- VLAN 200 (Loopbacks): 4 hosts
Show me a table with: VLAN, Network, Subnet Mask, Usable Range, Broadcast, Total Usable Hosts.
Sort by largest subnet first for efficient VLSM allocation.
What AI Gives You
A complete VLSM table sorted from largest to smallest subnet, with no overlaps, all fitting within your /22.
Review and Validate
- Verify no subnets overlap — AI is usually accurate but double-check boundary addresses
- Confirm usable host counts meet your requirements with room for growth
- Check that the total allocation does not exceed your /22 (1022 usable addresses)
Try It Yourself
Take your current network design and ask AI to review it for waste or overlap. Or ask it to redesign with better summarization.