This is a working MQTT-SN <-> MQTT gateway.
The code is taken from the Eclipse Paho project.
The reason is, that no one seems to know about this, nor use it.
I fixed some bugs.
On embedded devices the logging should be turned off.
Otherwise the MQTT-SN gateway is working pretty well.
I did not try the MQTT-SN c or java client
cd apps/MQTTSN-Gateway/src/org/eclipse/paho/mqttsn/gateway && javac -sourcepath ./ -d /target/path/ ./**/**/**/**/**/*.java ; cd ../../../../../../../..
there should be a more elegant way, if you know one, let me know, and i will change this
cd /target/path/ && /usr/bin/java org.eclipse.paho.mqttsn.gateway.Gateway
echo -e '\0x0a\0x04\0x04\0x01\0x00\0x660001' | nc -v -u localhost 20000
see notice.html
Please report bugs in Eclipse Bugzilla for the Paho project.
Discussion of the Paho clients takes place on the Eclipse paho-dev mailing list.
General questions about the MQTT protocol are discussed in the MQTT Google Group.
There is much more information available via the MQTT community site.