Each “thing” needs to send its data to an aggregating gateway node through what is sometimes called the “fog” layer.
Gateways perform two common functions.
First, they consolidate and route data from sensor devices to the appropriate data systems within the datacenter or cloud.
Second, they can analyze or aggregate device data and forward that data to the core systems and/or respond back to devices if a time-sensitive exception condition is noticed.
Gateway to data systems
The gateway is usually a much more capable computing device than the sensor, with a reliable and fast network connection.
So here the determination of what message protocols and qualities of service to use is driven not by the gateway’s computing capabilities or connectivity, but by data traffic patterns such as periodic bustiness and congestion, number of concurrent connections required, and security requirements.