Architecting IoT Solutions on Azure

Chapter 5. Device Messaging

I still remember the first time I ever sent someone a message through a computer in 1989. I typed in a brief message on my Intel 286 and sent it to a friend across town who used the same BBS. At that time, sending an electronic message to a computer across town or across the state may as well have been magic for most people. Then, electronic messaging was a novelty, but now it’s so common most people don’t even think about it. My exposure to electronic messaging was a bit before it became mainstream, but messaging has been around since long before I was born. The ability to send a message from device A to device B, then reverse that process and send it from device B to device A, was and still is one of the primary uses of the internet and devices. And while messaging has been around for a long time, it has not fundamentally changed much, even with IoT devices.

In the context of IoT, device messaging, simply put, is device-to-cloud (D2C) messaging and cloud-to-device (C2D) messaging. While these two categories are broad, there’s some nuance to these message types that relates to what goes into messages, how they are delivered, and what protocol, or language, is used to deliver them. Both of these messaging types imply that messages go in a particular direction. You already learned in Chapter 4 that messaging is part of a device’s main sequence to support its primary function. Messaging, therefore, falls into the same part of the IoT Landscape (Figure 5-1 ...