Abstract:
This Master's Thesis explores possibility to establish a service connection to distributed M2M terminal devices. The service connection can not be established directly because terminal devices are connected to networks which use network address translation or firewalls. For this reason, new software components were developed to enable the service connection in a way that command is given from the server but actual connection is established by the terminal device. The service connection was implemented using reverse tunnel provided by SSH software. SSH solved the network address translation problem but not the firewall problem. To bypass firewalls, the current measurement software was modified in a way that it is possible to force the terminal device to use GPRS connection instead of Ethernet because GPRS network has no firewalls. In testing phase, a Linux kernel and driver modules in terminal devices was updated using the service connection. Terminal devices were located in eight different countries and were installed on four different types of machinery. As a result, all the terminal devices succeeded to update.