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OpenThread-Whitefield Integration Aim

Validate OpenThread claims in realistic 802.15.4 environment possibly in standalone mode i.e., without having to worry about third-party OS quirks.

Using Whitefield it should be possible to test following:

  1. OpenThread scalability
    • max routers per BR
    • max child nodes per routers
    • max BRs
    • max hops
  2. Openthread performance under realistic conditions
    • Network convergence time
    • Node join time
    • packet delivery rate
    • Control Overhead incurred under different scenarios
    • Repair time (involving router failure, leader failure, BR failure)
    • Reboot handling of Router/Leader/BR
  3. Possible to simulate following scenarios
    • High node density scenario
    • Variable data-rate per node
    • Impact of node mobility
    • With and without memory constraints
    • Battery performance

OpenThread Integration Option

Integrate by adding new platform in core OpenThread

Adding a new platform of whitefield in OpenThread just like cc2538 or posix (already present in OpenThread). This option allows to directly use core OpenThread in Whitefield.

Advantage: Can test OpenThread in standalone mode without any dependency on another OS.

Disadvantage: In real world, the OpenThread core would be used along with some another OS/platform (such as Zephyr/RIOT/FreeRTOS). Only core-openthread could be tested with such integration mode.

This mode of integration best satisfies the aim mentioned above and this is the mode targeted first.

Integrate using existing OpenThread supported OS (RIOT/Zephyr/FreeRTOS)

Advantage: Get existing OpenThread integration support in existing popular IoT OS.

Disadvantage: Have to follow the quirks of the IoT OS used. If the aim is to validate OpenThread then this is unnecessary albeit counter-productive.

This should have been the simplest mode of integration but it means adding Whitefield as a platform/driver/target in RIOT/Zephyr/FreeRTOS. Currently Whitefield integrates with RIOT as a separate package and not as a platform/driver (just like OpenThread), and thus cannot use OpenThread (because two packages cannot be used together). Zephyr is not supported in Whitefield at the moment.

Whitefield works as a separate target currently only in Contiki. Unfortunately, Contiki does not support OpenThread integration at the moment.

Another option is to try OT-RTOS which is based on FreeRTOS, but it also requires to add platform support in FreeRTOS.

Integrate by externally attaching to Posix platform

This is the least intrusive mode of integration in OpenThread i.e., use existing posix platform and override radio transmit/receive (send/recv) with Whitefield transmit/receive using preloading techniques such as LD_PRELOAD, or GCC -wrap option.

Advantage: Can readily use any OpenThread binary directly in Whitefield.

Disadvantage: The preloaded lib needs to be in sync with OpenThread APIs. This is difficult to enforce with this mode of integration.

OpenThread TODOs

  1. Prepare call flows for documentation. This may help future drivers writing new porting interfaces.
  2. How is OpenThread-Whitefield different from OpenThread-Posix? a. ACKs are handled in Whitefield. (This is yet to be handled)

Current Stage for OpenThread Integration:

Have created a separate platform for whitefield in OpenThread. Commline init/deinit is handled but the actual commline send/recv is not handled as of now. In radioTransmit/Receive the posix-UDP send/recv is done to tx/rx messages. Using this I have verified that the Leader and Router node work fine. Steps to use the OpenThread integration:

  1. ./invoke_whitefield.sh config/wf_ot.cfg ... This step just turns on all the nodes but does not start the network.
  2. ./scripts/init_openthread_nodes.sh ... This step starts the openthread network subsystem. You can change this script if you want to use different config (for e.g., diff panID).

FAQs: