These components are the building blocks to get OpenThread integrated into the Windows networking stack and provide an interface for applications to control it.

Architecture

This design allows for support of both simple radio devices and devices running the complete OpenThread stack.

otApi.dll

This is the dynamic libray for applications to control the OpenThread stack from user mode. It exposes all the control path APIs from openthread.h. It interfaces with the driver by the use of IOCTLs. The IOCTLs allow otApi.dll to serialize and send commands, and poll for notifications, which can then be returned back to the client.

otLwf.sys

This is where most of the real logic lives. otLwf.sys is an NDIS Light Weight Filter (LWF) driver. It plugs into the networking stack, binding to a protocol driver (TCPIP) at the top, and an NDIS Miniport at the bottom. It's job is to take IPv6 packets from TCPIP and pass the necessary data down to the Miniport in order to send the packets out over the network.

otLwf.sys supports operating in two modes: Full Stack and Tunnel. Full Stack mode is where OpenThread is running on the host (in Windows) and a simple radio device is connected externally. Tunnel mode is where OpenThread is running on the external device and Windows is merely a pass through for commands and packets.

In Full Stack mode, otLwf.sys hosts the OpenThread core library and manages serializing all Windows networking inputs to the OpenThread APIs. It maintains one dedicated worker thread for running all OpenThread related logic, including IOCTL commands, data packets, and basic OpenThread processing logic. otLwf.sys uses OIDs to send control path commands (channel, panid, etc.) and NBLs to send and receive the 802.15.4 data packets to/from the miniport. The miniport then passes this information, in the proper format, off to the radio device.

In Tunnel mode, otLwf.sys mainly just manages the serialization of Windows networking inputs to Spinel commands (and back). The Spinel commands are passed down (in NBLs) to the miniport which will then pass the commands (correctly encoded) to whatever device is externally connected.

802.15.4 PHY Miniport

This is the component responsible for taking the OIDs and NBLs from otLwf.sys and sending the information down to the matching 802.15.4 PHY Device, in the proper format. In other words, it's job is mainly handling the arrival/removal of the physical device and serialization of the info in the proper format for the device it's paired with.

Thread Miniport

This is the component for taking the NBLs, containing Spinel commands, from otLwf.sys and sending them down to the matching OpenThread (NCP) Device. Again, like the PHY miniport, it's job is handling device arrival/removal and command serialization.

802.15.4 PHY Device

This is a 'simple' device, exposing a mostly PHY layer interface (with a few MAC layer constructs).

OpenThread (NCP) Device

This is a 'full solution' device, that exposes the entire OpenThread interface via NCP.

Build

Open the Visual Studio Solution openthread.sln under etc\visual-studio and then pick the configuration and platform you wish to build for. For instance, Release and x64. Build the whole solution (F6). This will output the files here:

build\bin\<platform>\<configuration>

Install

Filter Driver

Copy the following files to a temporary location on the target machine:

build\bin\<platform>\<configuration>\sys\otLwf.cer
build\bin\<platform>\<configuration>\sys\otLwf\otLwf.cat
build\bin\<platform>\<configuration>\sys\otLwf\otLwf.inf
build\bin\<platform>\<configuration>\sys\otLwf\otLwf.sys

Open an admin command prompt in the location of the temporary files.
Install the certificate to the root and TrustedPublisher store by running:

certutil -addstore root otLwf.cer
certutil -addstore TrustedPublisher otLwf.cer

Install the driver by running:

netcfg.exe -v -l otlwf.inf -c s -i otLwf

Miniport Driver

TODO

Controlling OpenThread from an Application

TODO