OML Labs is a browser-native, multi-vendor network simulator with the same drag-and-draw topology canvas GNS3 offers — minus the two-part install, the version-matched GUI client and the GNS3 VM you have to keep in sync. Plus an AI assistant that explains stuck protocols and one-clicks the fix.
GNS3 is a two-part setup: the GNS3 VM that runs the devices, plus the GNS3 desktop client you install — and version-match — on every machine. OML is a single OVA. Everyone on the team just opens a URL.
OSPF stuck in EXSTART? OML's NETO assistant reads the running config, finds the MTU mismatch and offers a one-click fix. It runs on a local Ollama LLM, so configs never leave the appliance. GNS3 has nothing equivalent.
OML labs can carry instructor-defined objectives that auto-grade student attempts and export to CSV for your LMS. GNS3 is a pure sandbox; OML is a sandbox plus a study and teaching tool.
For SD-WAN and large topologies the 2D canvas turns into spaghetti. OML adds an isometric 3D mode and a geographic map mode — pin sites to coordinates and watch tunnels. GNS3 is 2D only.
OML's Live Wire mode animates real frames moving across links, with RTT badges and drop markers, and streams a live Wireshark feed. In GNS3 you attach a capture and open Wireshark separately.
Browse and one-click-import ready-to-run labs (CCNA → CCIE) without leaving the canvas. GNS3's marketplace means downloading appliance files and importing them by hand.
No snake oil. GNS3 has been around since 2008 and has real strengths:
GNS3 has no paid tier and no node cap — ever. OML's free tier is capped at 5 nodes and charges above that. If budget is zero and you need large topologies, GNS3 is unbeatable on price.
Over a decade of forum threads, YouTube walkthroughs and a marketplace of appliances — including first-class Docker container support. OML's container support is still on the roadmap.
Bottom line: if you want a zero-cost, open-source sandbox and don't mind the two-part install, GNS3 is excellent. If you'd rather skip the desktop client entirely, want an AI co-pilot, lab scoring and live packet animation, and a free tier is enough to start — OML gets your team to "lab is running" without anyone installing software.
Free 5-node tier with full feature access — AI, snapshots, hot-plug, community labs. No credit card. One OVA that boots on every major hypervisor.