Method for managing handover roaming

A communication system comprises a first LPWAN network of a first operator and a second LPWAN network of a second operator. The first network comprises subnetworks implementing separate respective transport protocols. The subnetworks comprise at least one convergence node and communication nodes integrating gathering gateways. The first network comprises servers interconnected to a server of the second network interfacing an application server and an authentication server. Uplink frames of application data are transported from an end device of the second operator to the application server by successive relayings of the servers. However, when the end device of the second operator requests to join the communication system in order to benefit from the services of the application server, the gathering gateways communicate directly with the authentication server by shortcutting the other servers as well as the convergence nodes to which said gathering gateways are respectively attached.