Project: documenting a network (diagrams, IP plan, runbooks)
In short: Good documentation is what lets someone else run your network at 3 a.m. In this project you document a lab or small network properly, with diagrams at the right layers, an IP plan, an inventory, runbooks and a change log, and turn it into a strong portfolio piece.
Goal and requirements
The goal is a documentation set that a new engineer could use to understand, support and safely change a network without asking you. It is one of the most valued and least practised skills in junior engineers, so it stands out on a CV.
- A network to document: your home lab, a Packet Tracer design such as the small office project, or, with written permission, a real small network. Remove anything sensitive.
- Tools: diagrams.net (draw.io) or similar; a spreadsheet or NetBox for IP addresses and devices; Markdown in Git for runbooks.
- Standards: consistent names, icons, colours and a legend on every diagram.
Design
Agree a naming convention first, for example site-role-number such as hq-sw-01 and br1-rtr-01. Then build the IP plan, because diagrams refer to it.
| VLAN | Name | Subnet | Gateway | DHCP range |
|---|---|---|---|---|
| 10 | STAFF | 192.168.10.0/24 | 192.168.10.1 | .100 to .200 |
| 20 | GUEST | 192.168.20.0/24 | 192.168.20.1 | .100 to .250 |
| 30 | VOICE | 192.168.30.0/24 | 192.168.30.1 | .100 to .200 |
| 99 | MGMT | 192.168.99.0/24 | 192.168.99.1 | None (static) |
The VLSM calculator helps you size subnets without waste.
Build plan
- Discover: collect facts from each device with read-only commands and save the output.
- Fill in the inventory: hostname, model, serial, software version, management IP, location, support status.
- Draw the physical diagram, then the Layer 2 (VLANs, trunks) and Layer 3 (subnets, routing) diagrams. Add a legend, date and version to each.
- Write three runbooks with numbered steps, verification and rollback: add a VLAN, replace a failed switch, restore a config backup.
- Start a change log and record every change from now on.
- Optional: load the data into NetBox so it becomes a source of truth for automation.
show version
show inventory
show ip interface brief
show interfaces status
show vlan brief
show interfaces trunk
show cdp neighbors detail
show lldp neighbors detail
show ip route
show running-configgit clone -b release https://github.com/netbox-community/netbox-docker.git
cd netbox-docker
docker compose pull
docker compose up -dDeliverables and how to present it
- Three diagrams (physical, L2, L3) exported as PDF and kept as editable source files.
- IP plan and inventory as a spreadsheet or NetBox export.
- Three runbooks and a change log template with sample entries.
- A one-page "network at a glance" summary for managers.
On a CV: "Produced full documentation for a 4-VLAN, two-site network: layered diagrams, IP plan, inventory and runbooks with rollback steps." Interviewers often ask, "How would you hand over a network?" This project is your answer. Never publish real public IP addresses, serial numbers or passwords from any employer.
Practice
Why draw separate physical and logical diagrams?
What three parts should every runbook include?
Why create the IP plan before the diagrams?
Key takeaways
- Agree naming conventions before you document anything.
- Keep physical, Layer 2 and Layer 3 diagrams separate, with legends.
- An IP plan and inventory are the backbone of the set.
- Runbooks need steps, verification and rollback.
- Remove sensitive data before sharing any documentation.
Original content written by Mohamed Fayas for FM TecHub. © 2026 FM TecHub. You're welcome to share a link to this page; please don't copy the text elsewhere without permission.