What is Cisco Modeling Labs (CML), and why use network simulation at all?
CML is Cisco's commercial network-simulation platform whose virtual devices run the same code as real Cisco products. It lets you test configs, debug automation code and learn the APIs safely and cheaply, without real hardware or a production network.
* Driven through its REST API, a simulated lab becomes a pipeline step: build it, test the change on real Cisco code, tear it down. *
Network simulation lets you test configurations, debug configuration code, and work with Cisco infrastructure and its APIs safely, conveniently and at low cost. An automation script that wipes a VLAN in a simulation costs nothing. The same mistake in production can take down a site.
Facts about CML:
- Origin: a commercial product originally built for Cisco's internal use, with a broad and active community. The current version can run the whole simulation in the cloud.
- Realism: the virtual equipment runs the same code as the real Cisco devices, so behaviour matches what you would see on hardware.
- Local option: a limited CML setup can also run locally, for example in VirtualBox, with a limit of 5 active devices.
- Interfaces:
- a local CLI for system administration,
- a REST API for integrating it into automation, so a pipeline can create a lab, run pyATS tests on it and tear it down,
- a graphical UI for building and configuring topologies, with sample topologies such as a two-router IOS network to get started.
Go deeper:
Cisco Modeling Labs — Cisco DevNet — editions including the free 5-node tier.