Inspired by the sample code for the mDot, I have NetworkLinkCheck configured to request a downlink every 3 uplinks, and to fail if 2 are missed in a row.
Sure enough, I see in the Console that after every 3 uplinks there is a downlink. If I pull the plug on the gateway, or occasionally anyway (either because the gateway didn’t send the downlink or maybe because the node is too close and couldn’t hear it?) two downlinks are missed and I instruct the mDot to re-join.
ADR has a similar function, but it requires 48 uplinks without downlinks. I find it hard to imagine when such functionality would be useful. Surely either you can tolerate downlinks and therefore you may as well detect disconnections within 10 uplinks or so. Or you can’t tolerate downlinks and therefore are blind to disconnections.
It seems this is what NetworkLinkCheck offers - you request a downlink after every x uplinks and assume a disconnection if y of those are missed. With ADR moving to make the 48 configurable in LoRaWAN 1.1, will NetworkLinkCheck become redundant?