[From the last episode: There are various roles the CloudA generic phrase referring to large numbers of computers located somewhere far away and accessed over the internet. For the IoT, computing may be local, done in the same system or building, or in the cloud, with data shipped up to the cloud and then the result shipped back down. can play both for you and for manufacturers of IoTThe Internet of Things. A broad term covering many different applications where "things"  are interconnected through the internet. devices.]

The whole idea of “connected” is about being connected through the internet – and, in particular, to the cloud. But are there times when that connection might not be a good – or at least not an ideal – thing?

Yes! Consider the following cases:

• For privacyRefers to whether or not information gathered about your usage of IoT devices by authorized people can be made public, or shared with others, without your consent. Different from (although related to) security, which protects such data and devices from access by unauthorized people. Different from privacy, which is more concerned about use of data by authorized people. reasons, you might not want your personal data going to the cloud. That may or may not be possible, depending on your device/service provider or what the application is. This isn’t really what we’re going to talk about here, however.
• Businesses might be concerned about their own confidential data going into the cloud. This really is the same thing as privacy, so why didn’t I include it in the prior item? Because, realistically, businesses have more market power to negotiate such things than consumers do.
• It costs money to send data to the cloud. If you’re generating reams of data, you might not want to pay for all of it to go into the cloud.
• It takes time for messages to get to the cloud and back. Let’s take the case of a smart door lock: you use your phone app to unlock the door. That command goes to the cloud, and then the cloud sends a command back to your door lock that causes it to open. That takes a little time. Not a problem for unlocking? Well, what about if you’re trying to lock the door immediately in an emergency situation? That delay – even one second – would not be acceptable.

Using the Fog

So what happens if you have an application that requires the cloud, either so that you can use the phone as a “remote control” or for doing calculations or executing business rulesRules that say, "if this happens, then do that." Like, "if the ground is too dry, then turn on the sprinkler."? There’s a way that business can do something that’s kind of like the cloud, but it’s not public, and it’s not so far away. This is sometimes referred to in the industry as the fogRefers to some way of doing "cloud"-style computing without having to use the cloud. A local server (or router or something else) can act like the cloud; because it's local, it's referred to informally as the fog. – cloud-like stuff that’s close to the ground.

Let’s start with the need to protect sensitive data. Instead of using cloud serversA computer with a dedicated purpose. Older familiar examples are print servers (a computer that controls local printing) and file servers (a computer used for storing files centrally). More modern examples are web servers (the computers that handle your web requests when you use your browser) or application servers (computers dedicated to handling the computing needs of a specific application). Servers are often powerful, expensive machines since they have to handle a heavy load., you can use a private server – or multiple servers if needed – that you hostThe main processing unit in a system. It controls how all other processors in the system operate. It’s the boss. locally. The key is that you own (or at least control) the server.

You may remember way back when we introduced the four major components of the internet. For computing, we said that you could go to the cloud – or you could go to your own server nearby. The “own server” option is what the fog is all about.

Another example of this would be a speech-recognition device like the Amazon Echo or Dot. These use technology referred to as “Alexa” – you may have heard of this. Some people are concerned that Alexa is sending all conversations up into the cloud to be heard by anyone with access. While this is a reasonable concern, Amazon says, “That’s not how it works.”

They claim that they listen locally only for the wake wordFor personal assistants like the Amazon Echo, this is a word or phrase that the device listens for. When it hears it, it knows (or thinks) that you're going to give it a command. “Alexa” or “Echo”. Only then do they take the sounds that follow and send them up to the cloud. This lets them avoid the enormous amount of data that would be constantly transmitted otherwise.

At the current level of technology, other providers are likely to do the same thing. It’s important to remember, however, that, technically, it is possible for these devices to send everything to the cloud. If internet connectionsThis refers to some kind of electrical connection. It might be through a network cable, a cable connection, a wireless connection, or a phone - just to name some options. The connection might be to the internet or to some other local device. got bigger and cheaper (which they will), this listening policy could change. So we can’t become complacent.

So this is the notion of the fog. How do we actually put something together that does this fog thing? That’s the subject of the next post.