Border router device guide for Android

Android app developers can use the Home APIs to manage a Thread Border Router (TBR).

The GoogleBorderRouterDevice is implemented using two primary device traits: ThreadNetworkCapabilities, which provides read-only attributes to inspect border router features, and ThreadNetworkManagement, which handles network lifecycle commands and credential sharing using an Ephemeral Pre-Shared Key for the Commissioner (ePSKc). Structure-level internet access policies are managed using the ThreadNetworkSettings trait.

Always check for attribute and command support for a device prior to using any features or attempting to update attributes. See Control devices on Android for more information.

Home APIs Device Type Traits Kotlin Sample App Use Case

Border Router

GoogleBorderRouterDevice

home.matter.6006.types.0161

 Required Traits
     google ThreadNetworkCapabilities
     google ThreadNetworkManagement

 Border Router

Get basic information about a device

   Implemented in Sample App for Android   

The BasicInformation trait includes information like vendor name, vendor ID, product ID, product name (includes model information), and software version for a device:

// Get device basic information. All general information traits are on the RootNodeDevice type.
    device.type(RootNodeDevice).first().standardTraits.basicInformation?.let { basicInformation ->
        println("vendorName ${basicInformation.vendorName}")
        println("vendorId ${basicInformation.vendorId}")
        println("productId ${basicInformation.productId}")
        println("productName ${basicInformation.productName}")
        println("softwareVersion ${basicInformation.softwareVersion}")
    }

Inspect border router capabilities

You can examine a border router's read-only capabilities (such as ePSKc support and Internet Access setting configuration) using the ThreadNetworkCapabilities trait.

suspend fun checkBorderRouterCapabilities(device: HomeDevice) {
    // Filter for GoogleBorderRouterDevice device type
    val gtbrDevice = device.type(GoogleBorderRouterDevice).firstOrNull()
    if (gtbrDevice == null) {
        println("Device is not a Google border router.")
        return
    }

    // Retrieve the ThreadNetworkCapabilities trait
    val capabilitiesTrait = gtbrDevice.trait(ThreadNetworkCapabilities)
    if (capabilitiesTrait == null) {
        println("ThreadNetworkCapabilities trait not found on device.")
        return
    }

    val isEpskcSupported = capabilitiesTrait.epskcSupported ?: false
    val internetAccessOption = capabilitiesTrait.internetAccessOption?.name ?: "None"
    val isIasSupported = !internetAccessOption.equals("None", ignoreCase = true)

    println("ePSKc Supported: $isEpskcSupported")
    println("Internet Access Setting Supported: $isIasSupported")
}

Manage Thread credential sharing (ePSKc)

Thread credential sharing is achieved using an Ephemeral Pre-Shared Key for the Commissioner (ePSKc). ePSKc mode generates a temporary, secure passkey that external devices or commissioners can use to securely obtain the Thread network dataset.

Activate ePSKc mode

suspend fun startEpskcSession(device: HomeDevice, durationSeconds: Short): ActivateEpskcModeCommand.Response? {
    val gtbrDevice = device.type(GoogleBorderRouterDevice).firstOrNull()
    val mgmtTrait = gtbrDevice?.trait(ThreadNetworkManagement)

    if (mgmtTrait == null) {
        println("ThreadNetworkManagement trait not found.")
        return null
    }

    return try {
        val response = mgmtTrait.activateEpskcMode(
            optionalArgs = { this.requestedDurationSeconds = durationSeconds }
        )

        println("ePSKc Session Activated!")
        println("Status: ${response.status}")
        println("Ephemeral PSKc: ${response.epskc}")
        println("Valid Duration (s): ${response.validDurationSeconds}")

        response
    } catch (e: Exception) {
        println("Failed to activate ePSKc mode: ${e.message}")
        null
    }
}

Deactivate ePSKc mode

suspend fun stopEpskcSession(device: HomeDevice) {
    val gtbrDevice = device.type(GoogleBorderRouterDevice).firstOrNull()
    val mgmtTrait = gtbrDevice?.trait(ThreadNetworkManagement)

    mgmtTrait?.deactivateEpskcMode()
    println("ePSKc mode deactivated.")
}

Observe ePSKc deactivation events

TBRs emit events when an ePSKc session ends (for example, because the key was used, the session expired, or it was manually cancelled).

suspend fun observeEpskcEvents(device: HomeDevice) {
    val gtbrDevice = device.type(GoogleBorderRouterDevice).firstOrNull()
    val mgmtTrait = gtbrDevice?.trait(ThreadNetworkManagement)

    mgmtTrait?.epskcModeDeactivatedEventFlow()?.collect { event ->
        println("ePSKc Session Ended. Reason: ${event.reason}")
        when (event.reason?.name) {
            "KeyUsed" -> println("Key was successfully used to commission a device.")
            "Expired" -> println("Session timed out before the key was used.")
            "Cancelled" -> println("Session was manually cancelled.")
        }
    }
}

Manage Thread network membership

You can command a TBR to join a new Thread network by providing the active Operational Dataset TLVs, or command it to leave its current network.

suspend fun joinNetwork(device: HomeDevice, datasetTlvs: ByteArray) {
    val gtbrDevice = device.type(GoogleBorderRouterDevice).firstOrNull()
    val mgmtTrait = gtbrDevice?.trait(ThreadNetworkManagement)

    try {
        val response = mgmtTrait?.joinNetwork(operationalDatasetTlvs = datasetTlvs)
        println("Join network command sent. Status: ${response?.status}")
    } catch (e: Exception) {
        println("Join network failed: ${e.message}")
    }
}

suspend fun leaveNetwork(device: HomeDevice) {
    val gtbrDevice = device.type(GoogleBorderRouterDevice).firstOrNull()
    val mgmtTrait = gtbrDevice?.trait(ThreadNetworkManagement)

    try {
        mgmtTrait?.leaveNetwork()
        println("Leave network command sent successfully.")
    } catch (e: Exception) {
        println("Leave network failed: ${e.message}")
    }
}

Configure structure-level internet access

The ThreadNetworkSettings trait is an updatable trait attached to a Structure (representing a home or building). It allows developers to configure the structure-wide internet access policy for TBRs.

suspend fun updateStructureInternetAccess(structure: Structure, enableInternetAccess: Boolean) {
    // Retrieve the ThreadNetworkSettings trait for the structure
    val settingsTrait = structure.trait(ThreadNetworkSettings).firstOrNull()
    if (settingsTrait == null) {
        println("ThreadNetworkSettings trait not found on structure.")
        return
    }

    val option = if (enableInternetAccess) {
        InternetAccessOption.InternetAccessOptionAll
    } else {
        InternetAccessOption.InternetAccessOptionNone
    }

    try {
        settingsTrait.update {
            setInternetAccessOption(option)
        }
        println("Successfully updated Thread internet access policy to: ${option.name}")
    } catch (e: Exception) {
        println("Failed to update Thread internet access policy: ${e.message}")
    }
}