The gateways offer a Physical hardware interface that offers and Ethernet, WIFI, or Cellular connection to send the data to and from a cloud or other server. They also offer a processor in which you can write and host an application that can do what ever functions you desire. That is, they can take the data that comes in over a Zigbee, Digi Mesh or network, look at that data, determine what to do with that data. Then send the data when desired.