Consider a moving LoRaWAN end-device, while transmitting data, such as a tracking application.

First case: the end-device within the coverage of gateways belonging to a network server (Home NS).

Second case: the end-device is out of the cover of Home NS.

For the first case, the end device is only uplink the data and any gateway reception will be forwarded to Home NS.

But in the second case, I noticed that LoRaWAN 1.1 was taking charge of roaming.

Q1- But with even roaming support, how will the device detect that the coverage of Home NS is no longer available and its now under the coverage of new NS (Visited NS)?

In my understanding, class C always listen to RX2, so when location changes class C detects this change by the new beacons received on RX2 holding the prefix ID of Visit NS. Class B is the same, listen periodical on RX2. But Class A will transmit without listening or detect. After the transmission Class A will detect that under the coverage of visited NS. Class A transmission will cause interference and collision with current devices on the visited network.

Q2- What is the difference between passive and handover roaming? Which one is better in the case above? Or listen before talk LBT is better?