Welcome to WalT documentation!

The WalT project allows to easily build and use your own WalT testbed. Up to now, WalT testbeds have been used for research experiments, medium-sized (e.g., 100 nodes) industrial testing infrastructures, and mobile demo setups.

Scope and design notes

WalT is designed as a tool for teammates. If many users want to use WalT, then each team should install its own private WalT platform. Much of the versatility and user-friendliness we advertise comes from this concept of private platform. See walt help show design-notes for more info.

Main features

WalT mainly provides the following set of features:

  • Physical access (see below) and/or remote control over nodes

  • Compatibility with various kinds of nodes:

    • Raspberry Pi B/B+/2B/3B/3B+/4B/400 nodes

    • PC nodes booted from a USB dongle

    • Virtual nodes

    • Distant Raspberry Pi nodes using WALT ssh-based VPN (experimental feature)

  • Management of node OS images

    • Clone or publish them from/to the docker hub (or a private registry)

    • Modify them easily (virtual shell sessions, 1-command file copies)

  • Means to collect, store and query experiment logs

A WALT platform is cost-effective, easy to install, easy to use, lightweight, versatile and collaborative.

Optional features

With compliant network switches, WalT also provides the following optional features:

  • Platform topology automated discovery;

  • PoE for simplified deployment, possible hard-reboot (power-cycling) of nodes and automatic power saving.

See walt help show optional-features for more info.

A key feature: giving users physical access to nodes

WalT platforms provide a high level of versatility: they give users physical access to nodes. At LIG for instance, our main WalT platform network is deployed over a VLAN of the building. Users can plug or unplug walt nodes (or, sometimes, network switches) from the wall plugs depending on the experiments they plan.

Debugging low-level kernel modifications of a network protocol is obviously much easier when having physical access to two or more of these nodes; with such a setup, the user can easily move two WalT nodes right to her desktop.

Moreover, users often use the USB ports of WalT nodes to plug other equipment. For instance it is easy to setup an IoT testbed by connecting IoT boards on USB ports of WalT nodes. In this case, the experiment runs on the IoT boards and WalT nodes are configured as a control interface for them. WalT nodes boot a WalT image containing tools to flash a firmware or reboot the IoT board, and possibly catch the logs coming for the USB-serial link and turn them into WalT logs.

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