ONLINE NETWORK SIMULATOR

Build a network.
Understand every connection.

nuLAB is a browser-based network simulator for building topologies, practicing CLI configuration, and investigating routing and switching behavior. Open a lab, make a change, and inspect what happens.

Start a network lab Explore plans

Getting started / network labEXAMPLE

192.168.10.0 / 24

R1 · Edge router

R1# show ip interface brief

Interface        IP-Address     Status  Protocol
GigabitEthernet0/0 192.168.10.1   up      up
GigabitEthernet0/1 10.0.0.1       up      up

Select a device to explore sample CLI output.

TOPOLOGY → CONFIGURATION → EVIDENCE

Bring the diagram and the CLI together.

A diagram shows how devices connect. A lab lets you investigate why they communicate—or why they do not. Use the topology and terminal together to connect networking concepts with the simulated state of each device.

Build your topology

Place supported routers, switches, and endpoints. Connect their interfaces and give each device a clear role in your scenario.

Practice network CLI

Open a device terminal, configure supported features, and inspect interfaces, routes, or VLANs. Command coverage depends on the selected device profile.

Explain the result

Use reachability checks and device state to test your expectation. Trace a failure back to addressing, a link, or the configuration you changed.

YOUR FIRST EXPERIMENT

Start small. Make the result explainable.

Connect two endpoints to a switch and add a router as their gateway. Use one subnet first. Check interface state and addressing before adding another network or routing protocol.

Write down the endpoint addresses, subnet mask, and default gateway.
Check that the intended interfaces are connected and enabled.
Test the local gateway, then the other endpoint. Compare the result with your prediction.

These are suggested checks for suitable profiles, not a promise that every device implements the same syntax. Review device compatibility before choosing your lab.

Questions to ask at the terminalEXAMPLE

# Are the interfaces up and addressed?
show ip interface brief

# Does the router know the destination?
show ip route

# Can the endpoint reach its gateway?
ping 192.168.10.1

Illustrative commands for a compatible lab. The comments describe the investigation; they are not commands to enter.

CHOOSE THE RIGHT LAB

A simulator for supported network behavior.

nuLAB models network devices and supported protocol behavior in software. You do not need a physical equipment rack or a proprietary device image to start a standard nuLAB lab.

What to explore—and what to verify elsewhere
Your question	Use nuLAB for	Keep in mind
How does this work?	Addressing, supported CLI configuration, routing, switching, and connectivity exercises.	Available commands and protocol details vary by profile and plan.
What if I change this?	Comparing simulated network state before and after a controlled configuration change.	A successful simulation does not establish production correctness.
Will this hardware perform?	Understanding the logical topology that you intend to test.	Use appropriate hardware or other testing for throughput, optics, ASIC behavior, and exact appliance parity.

BEFORE YOU START

A few useful answers.

Is nuLAB a simulator or an emulator?

nuLAB is a simulator. It models supported network behavior and does not run the original device operating system. The standard offering does not distribute proprietary third-party operating system images. Read the platform disclaimer for the full boundaries.

Do I need to install software or own networking hardware?

You access the nuLAB workspace and device terminals through your browser. An internet connection and an account with suitable access are required; a physical networking rack is not required for simulated labs.

Can I start from a prepared lab?

Yes. Browse published scenarios in the Marketplace. Installing a pack and using its interactive content depend on the pack’s availability, your plan, and any required entitlement.

Does every command from a physical device work?

No. Simulation covers supported commands and behavior for each profile. Review the compatibility section and verify the specific commands needed for your exercise.

TAKE THE NEXT STEP

Turn one question into a working lab.

Start with a small topology and a clear expected result. Build your understanding one observable change at a time.

Create your account

Build a network.Understand every connection.