Depending on the requirements of the user, this could be as simple an action as ringing a buzzer or sending an alert by SMS that there is an abnormality.
More frequently, it is a web page, or dashboard, with a series of graphs showing real-time information from the network. Many cloud platforms now include tools to visualise data instead of creating separate traditional web pages to display it.
This may also include an automated feedback loop or manual two-way communication – the user may wish to input into the system to control the sensors or an actuator based on the information they have received.