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Free and Cheap Lab Platforms Compared

Six platforms cover almost every network lab you will want to build at home or at work: Cisco Modeling Labs, EVE-NG Community, GNS3, Containerlab, Cisco DevNet Sandbox and Juniper vLabs. This article says what each one is, how images are licensed, what hardware it needs and which kind of engineer it suits. Prices and node limits change, so check the vendor page before you commit.

The short version

Platform Type Licence Images Runs where
CML Free / Personal Full lab appliance with web UI Commercial; a free tier exists with a small node limit Cisco reference images included Your hardware or a hypervisor
EVE-NG Community Web UI lab server Free Community edition, paid Pro You supply every image Your hardware or a hypervisor
GNS3 GUI client plus server Open source (GPL) You supply every image Your PC, or a remote GNS3 server
Containerlab CLI tool, YAML topologies Open source Containers are free; VM-based NOS images are yours to obtain Any Linux host with Docker
DevNet Sandbox Hosted by Cisco Free Provided Cisco's infrastructure
Juniper vLabs Hosted by Juniper Free with an account Provided Juniper's infrastructure

Cisco Modeling Labs (CML)

CML is Cisco's own lab product. You install it as a VM or on bare metal and use it from a browser. It ships with a library of reference images (IOSv, IOSvL2, CSR1000v or Catalyst 8000v, NX-OSv 9000, IOS XRv, ASAv and others, depending on the version), so you do not hunt for images or worry about whether they are legal to use.

  • Free tier. CML-Free is limited to a small number of nodes per lab (check the current limit on the Cisco page) and has fewer features than the paid editions. It is enough for a BGP or OSPF lab with four or five routers. It will not host an EVPN fabric of two spines and four leaves.
  • Personal. A paid annual licence with a larger node count. Cisco publishes the price on its site; check the current price rather than trusting a blog.
  • Strengths. Images are legitimate and supported, the UI is clean, there is an API for automation, and external connectors let you bridge a lab to your physical network.
  • Weaknesses. Node limits, a licence you must renew, and a heavy appliance. The NX-OS and IOS XE nodes want real RAM.
  • Fits. Engineers who want a supported, low-friction Cisco lab and are happy to pay for it or stay inside the free tier.

EVE-NG Community

EVE-NG is a lab server with an HTML5 interface. The Community edition is free. The Pro edition adds features such as clustering and a richer UI and is paid.

  • Images. EVE-NG supplies none. You bring your own, from a Cisco licence, vendor downloads or other sources you are entitled to use. This is the biggest practical hurdle and the main legal question: make sure you are allowed to use each image you load.
  • Strengths. Supports a very wide range of vendors, runs QEMU, Docker and IOL (IOS on Linux) nodes, and has a large community with prebuilt guides.
  • Weaknesses. Image preparation is manual and fiddly, the Community edition has fewer features than Pro, and everything lives in one server VM so a big topology needs a big host.
  • Fits. Multi-vendor labs and engineers who already own images and want a browser-based canvas.

GNS3

GNS3 is open source software. A GUI client talks to a GNS3 server, which can run on your laptop or on a separate machine. It started with Dynamips, which emulates older Cisco router hardware and runs real IOS images, and now also runs QEMU, Docker, VirtualBox and VMware nodes.

  • Images. You supply them. The GNS3 project distributes no Cisco images.
  • Strengths. Free, scriptable, flexible, and the remote server option lets a weak laptop drive a strong lab host. Good documentation. A marketplace of appliance templates helps with importing images.
  • Weaknesses. Dynamips only covers legacy router platforms. Modern devices such as NX-OS or IOS XE need QEMU and a lot of RAM. The topology is stored as a project file, so diffing and sharing is clumsier than with a YAML file.
  • Fits. Engineers who want an open source tool with a desktop GUI and who care about owning the whole stack.

Containerlab

Containerlab builds labs from a YAML file and runs nodes as containers on a Linux host. You define nodes and links, run containerlab deploy -t topo.clab.yml, and have a lab in seconds.

name: demo
topology:
  nodes:
    leaf1:
      kind: nokia_srlinux
      image: ghcr.io/nokia/srlinux
    leaf2:
      kind: nokia_srlinux
      image: ghcr.io/nokia/srlinux
  links:
    - endpoints: ["leaf1:e1-1", "leaf2:e1-1"]
  • Images. Several network operating systems ship as containers, including Nokia SR Linux, FRRouting and Linux hosts. Arista cEOS is available as a download after you register with Arista. Other platforms, including Cisco ones, run through the vrnetlab project, which wraps a vendor VM image in a container. For those you need to obtain the VM image yourself.
  • Strengths. Fast to start, tiny footprint compared with full VMs, the topology is a text file that lives in git, and it fits CI pipelines well.
  • Weaknesses. It is a Linux and Docker tool, with no GUI canvas. A VM-based node is as heavy as it is anywhere else. Anything that depends on a vendor VM image still has the image problem.
  • Fits. Automation-minded engineers, anyone testing configs in CI, and anyone building data centre labs with lightweight NOSes.

Cisco DevNet Sandbox

DevNet Sandbox gives you hosted Cisco environments for free. There are two models. Always-on sandboxes are shared and ready at any time. Reservation sandboxes give you a private slot for a limited time, after which the environment is torn down.

  • Resources. None on your side. You connect over the internet, often with a VPN, and use the device CLI, NETCONF, RESTCONF or an API.
  • Strengths. Zero setup, real platforms, good for learning APIs and model-driven programmability. Catalogue entries cover IOS XE, NX-OS, SD-WAN, ACI and others, and what is on offer changes over time.
  • Weaknesses. You cannot build arbitrary topologies. Reservation sandboxes expire and you cannot count on a slot at a given hour. Always-on sandboxes are shared, so someone else may have changed the config.
  • Fits. Automation practice (Netmiko, NAPALM, RESTCONF) and quick tests on a platform you do not have at home.

Juniper vLabs

vLabs is Juniper's hosted lab service. You sign in with a Juniper account, reserve a lab for a slot and get access to preconfigured Junos topologies.

  • Strengths. Free, no local resources, and good for Junos practice and for the Juniper certification track.
  • Weaknesses. Fixed topologies and reservation windows. Not a place to build your own design.
  • Fits. Engineers learning Junos or testing Juniper behaviour who do not want to download images.

Image licensing in practice

This is where most home labs get in trouble. Three rules keep you safe:

  1. Cisco images obtained through CML come with the CML licence. Images from other sources are covered by whatever licence you hold for them.
  2. Free and open source tools (GNS3, EVE-NG Community, Containerlab) do not include proprietary vendor images. You must obtain those lawfully.
  3. Open source routing stacks (FRRouting, BIRD) and Linux have no such restriction and are useful when you only need to learn the protocol, not the vendor CLI.

Warning

Do not download images from file-sharing sites. Besides licence risk, you cannot trust what is inside them. Lab images often get management access to your network.

Sizing your lab host

Memory is the limit, not CPU. Rough rules of thumb that hold across tools:

  • IOS XE virtual routers want a few GB of RAM each.
  • NX-OS 9000v nodes are the heaviest, typically 8 GB or more per node, so an EVPN fabric needs a server-class machine.
  • IOL and container nodes need a few hundred MB each.
  • Linux and FRR containers are almost free.

Check the release notes of the image you use for exact figures. They change between versions. If your PC cannot carry the lab, run a lab server on a spare machine or a rented cloud VM and connect remotely. Nested virtualisation must be enabled for the VM-based tools.

Which one should you pick

graph TB
    A["What do you want to do?"] --> B["Learn APIs or try a platform fast"]
    A --> C["Build my own topology"]
    B --> D["DevNet Sandbox or Juniper vLabs"]
    C --> E["I want Cisco images included"]
    C --> F["I own images or use Linux NOS"]
    E --> G["CML Free or Personal"]
    F --> H["Need a GUI canvas"]
    F --> I["Need text files and CI"]
    H --> J["EVE-NG Community or GNS3"]
    I --> K["Containerlab"]

A reasonable combination for a working engineer is Containerlab for fast routing-protocol and automation tests, plus either CML or EVE-NG for vendor-specific CLI work, plus DevNet Sandbox for anything you cannot fit at home. The labs in this section (BGP, OSPF, EVPN VXLAN) are written for IOS XE and NX-OS nodes and will run on CML, EVE-NG or GNS3 given the images. For exam preparation see the CCNP lab setup page.

References