About

This application demonstrates the usage of the emCute (MQTT-SN) module in RIOT.

Setup

For using this example, two prerequisites have to be fullfilled:

1. You need a running MQTT broker that supports MQTT-SN or a running MQTT-SN gateway that is connected to a running MQTT broker
2. Your RIOT node needs to be able to speak to that broker/gateway

Setting up a broker

In general, any MQTT-SN capable broker or broker/gateway setup will do. Following a quick instruction on how-to setup the Mosquitto Real Simple Message Broker:

1. Get the RSMB here: https://github.com/eclipse/mosquitto.rsmb:

   git clone https://github.com/eclipse/mosquitto.rsmb.git
   

2. Go into the source folder and build the RSMB

   cd mosquitto.rsmb/rsmb/src
   make
   

3. Create a config file. In this case we run the RSMB as MQTT and MQTT-SN capable broker, using port 1885 for MQTT-SN and 1886 for MQTT and enabling IPv6, so save the following to config.conf:

   # add some debug output
   trace_output protocol
   

listen for MQTT-SN traffic on UDP port 1885

listener 1885 INADDR_ANY mqtts ipv6 true

listen to MQTT connections on tcp port 1886

listener 1886 INADDR_ANY ipv6 true

4. Start the broker:

./broker_mqtts config.conf

You can refer to
https://rawgit.com/MichalFoksa/rsmb/master/rsmb/doc/gettingstarted.htm for more
configuration options.


### Setting up RIOT `native`
When running this example under native, we must configure some global addresses,
as the RSMB doesn't seems to be able to handle link-local addresses. So for a
single RIOT native instance, we can do the following:

1. Setup `tap` and `tapbr` devices using RIOT's `tapsetup` script:

./RIOTDIR/dist/tools/tapsetup/tapsetup

2. Assign a site-global prefix to the `tapbr0` interface (the name could be
   different on OSX etc):

sudo ip a a fec0:affe::1/64 dev tapbr0

3. Assign a site-global address with the same prefix to the RIOT `native`
   instance:

ifconfig 5 add fec0:affe::99

## Usage
This example maps all available MQTT-SN functions to shell commands. Simply type
`help` to see the available commands. The most important steps are explained
below:

- To connect to a broker, use the `con` command:

con fec0:affe::1 1885

- To subscribe to a topic, run `sub` with the topic name as parameter, e.g.

sub hello/world

- For publishing, use the `pub` command:

pub hello/world "One more beer, please."

That's it, happy publishing!