This application is the simplest one to utilize our mesh networking stack. It just joins your device to the unsecure 6LoWPAN-ND network. The canonical source for this example lives at

Example mesh application for Mbed OS

With this application, you can use our mesh networking stack. This application joins your device to the unsecure 6LoWPAN-ND network.


Building with Mbed CLI

If you'd like to use Mbed CLI to build this offline, then you should refer to the Mbed CLI documentation. The instructions here relate to using the Mbed Online Compiler

  1. Click `Import this application` button.
  2. Change the channel settings: See the file `mbed_app.json` for an example of defining an IEEE 802.15.4 channel to use.
  3. Compile the application

A binary is generated at the end of the build process.

Connect the RF shield to the board

By default, we are using the Atmel AT86RF233, which you can purchase. Place the shield on top of your board, and power it on.

Program the target

Drag and drop the binary to the target to program the application.

Update the firmware of the border router.

You can read the instructions on updating the firmware of your board working as 6LoWPAN border router here.

Please remember to connect the Ethernet cable between the border router and your router. Then, power up the board.


As soon as both the border router and the target are up and running, you can verify the correct behavior. Open a serial console, and see the IP address obtained by the device.

Note: This application uses a baud rate of 115200.


connected. IP = 2001:db8:a0b:12f0::1

You can use this IP address to ping from your PC and verify that the connection is working correctly.

Changing the radio driver (optional)

To run a 6LoWPAN-ND network, you need a working RF driver for Nanostack. This example uses the Atmel AT86RF233 by default.

To change the RF driver:

  1. Uninstall the Atmel RF driver.
  2. Install the new driver. (For example, for the FRDM-CR20A radio shield based on the MCR20A device.)
  3. Recompile your application.


4 weeks ago

File content as of revision 128:e7faff9c9fd9:

 * Copyright (c) 2016 ARM Limited. All rights reserved.
 * SPDX-License-Identifier: Apache-2.0
 * Licensed under the Apache License, Version 2.0 (the License); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
#include "mbed.h"
#include "nanostack/socket_api.h"
#include "mesh_led_control_example.h"
#include "common_functions.h"
#include "ip6string.h"
#include "mbed-trace/mbed_trace.h"

static void init_socket();
static void handle_socket();
static void receive();
static void my_button_isr();
static void send_message();
static void blink();
static void update_state(uint8_t state);
static void handle_message(char* msg);

#define multicast_addr_str "ff15::810a:64d1"
#define TRACE_GROUP "example"
#define UDP_PORT 1234
#define MASTER_GROUP 0
#define MY_GROUP 1

DigitalOut led_1(MBED_CONF_APP_LED, 1);
InterruptIn my_button(MBED_CONF_APP_BUTTON);
DigitalOut output(MBED_CONF_APP_RELAY_CONTROL, 1);

NetworkInterface * network_if;
UDPSocket* my_socket;
// queue for sending messages from button press.
EventQueue queue;
// for LED blinking
Ticker ticker;
// Handle for delayed message send
int queue_handle = 0;

uint8_t multi_cast_addr[16] = {0};
uint8_t receive_buffer[20];
// how many hops the multicast message can go
static const int16_t multicast_hops = 10;
bool button_status = 0;

void start_mesh_led_control_example(NetworkInterface * interface){

    network_if = interface;
    stoip6(multicast_addr_str, strlen(multicast_addr_str), multi_cast_addr);

static void blink() {
    led_1 = !led_1;

void start_blinking() {
    ticker.attach(blink, 1.0);

void cancel_blinking() {

static void send_message() {
    tr_debug("send msg %d", button_status);

    char buf[20];
    int length;

    * Multicast control message is a NUL terminated string of semicolon separated
    * <field identifier>:<value> pairs.
    * Light control message format:
    * t:lights;g:<group_id>;s:<1|0>;\0
    length = snprintf(buf, sizeof(buf), "t:lights;g:%03d;s:%s;", MY_GROUP, (button_status ? "1" : "0")) + 1;
    MBED_ASSERT(length > 0);
    tr_debug("Sending lightcontrol message, %d bytes: %s", length, buf);
    SocketAddress send_sockAddr(multi_cast_addr, NSAPI_IPv6, UDP_PORT);
    my_socket->sendto(send_sockAddr, buf, 20);
    //After message is sent, it is received from the network

// As this comes from isr, we cannot use printing or network functions directly from here.
static void my_button_isr() {
    button_status = !button_status;;

static void update_state(uint8_t state) {
    if (state == 1) {
       tr_debug("Turning led on\n");
       led_1 = 0;
       output = 0;
    else {
       tr_debug("Turning led off\n");
       led_1 = 1;
       output = 1;

static void handle_message(char* msg) {
    // Check if this is lights message
    uint8_t state=button_status;
    uint16_t group=0xffff;

    if (strstr(msg, "t:lights;") == NULL) {

    if (strstr(msg, "s:1;") != NULL) {
        state = 1;
    else if (strstr(msg, "s:0;") != NULL) {
        state = 0;

    // 0==master, 1==default group
    char *msg_ptr = strstr(msg, "g:");
    if (msg_ptr) {
        char *ptr;
        group = strtol(msg_ptr, &ptr, 10);

    // in this example we only use one group
    if (group==MASTER_GROUP || group==MY_GROUP) {

static void receive() {
    // Read data from the socket
    SocketAddress source_addr;
    memset(receive_buffer, 0, sizeof(receive_buffer));
    bool something_in_socket=true;
    // read all messages
    while (something_in_socket) {
        int length = my_socket->recvfrom(&source_addr, receive_buffer, sizeof(receive_buffer) - 1);
        if (length > 0) {
            int timeout_value = MESSAGE_WAIT_TIMEOUT;
            tr_debug("Packet from %s\n", source_addr.get_ip_address());
            timeout_value += rand() % 30;
            tr_debug("Advertisiment after %d seconds", timeout_value);
            queue_handle = queue.call_in((timeout_value * 1000), send_message);
            // Handle command - "on", "off"
        else if (length!=NSAPI_ERROR_WOULD_BLOCK) {
            tr_error("Error happened when receiving %d\n", length);
        else {
            // there was nothing to read.

static void handle_socket() {
    // call-back might come from ISR;

static void init_socket()
    my_socket = new UDPSocket();
    my_socket->setsockopt(SOCKET_IPPROTO_IPV6, SOCKET_IPV6_MULTICAST_HOPS, &multicast_hops, sizeof(multicast_hops));

    ns_ipv6_mreq_t mreq;
    memcpy(mreq.ipv6mr_multiaddr, multi_cast_addr, 16);
    mreq.ipv6mr_interface = 0;

    my_socket->setsockopt(SOCKET_IPPROTO_IPV6, SOCKET_IPV6_JOIN_GROUP, &mreq, sizeof mreq);

    //let's register the call-back function.
    //If something happens in socket (packets in or out), the call-back is called.
    // dispatch forever