So am I correct in saying the gateway gives no guaantee that a message a controller asks it to send will actually reach a node ?

Presumably you would have to have a sensor on the node that could read the state of the switch so the controller could send the message then conform it was received.

It would be good in that event to have a ping capability on the node so that if the node loses communication wih the gateway (or controller) that it could put itself in a default state. In the case of a sprinkler, that could be an off state.

I'm looking at using MySensors for various controls and it looks pretty good so far, but I have been unable to locate anything that indicates if it uses a guaranteed delivery protocol or a best effort. Eg, if I used it to control a sprinkler valve and a repeater sends out a message to turn it off but the receiver misses the 1st message, what happens ? Does the sprinkler valve get left on or will it retry the transmission ?

It seems to have eventually become recognised, but it took over an hour of just sitting there. I have no idea why it decided to start working.

I have a vera edge with mysensors installed. I have an arduino nano and an NRF24 connected as per the "Building a serial gateway" page descibed at https://www.mysensors.org/build/serial_gateway

If the arduino is connected to my PC I see info like the following in the serial monitor

0;255;3;0;9;MCO:BGN:INIT GW,CP=RNNGA--,VER=2.1.1
0;255;3;0;9;TSM:INIT
0;255;3;0;9;TSF:WUR:MS=0
0;255;3;0;9;TSM:INIT:TSP OK
0;255;3;0;9;TSM:INIT:GW MODE
0;255;3;0;9;TSM:READY:ID=0,PAR=0,DIS=0
0;255;3;0;9;MCO:REG:NOT NEEDED
0;255;3;0;14;Gateway startup complete.
0;255;0;0;18;2.1.1
0;255;3;0;9;MCO:BGN:STP
0;255;3;0;9;MCO:BGN:INIT OK,TSP=1

Apart from the power LED on the arduino, it looks like the green LED is probably flashing very fast as its about half brightness.

If I connect the usb port on the nano to the USB port on the vera then look in the vera under "apps/develop apps/serial port configuration" next to the save button is the message "Not available". Is this the correct wiring or am I missing something ?

I have tried power cycling the vera but that hasn't made any difference.