As we have already seen in the first post published by Juanjo Bagüés “What is home automation? Where do you buy it? How much does it cost?” With the term domotics, we are not talking about automation in tasks such as raising blinds, but we are going to try to go a little further. That beyond is defined in parameters such as efficiency, consumption, comfort, etc.
But how do we make all the devices we need for an efficient home automation system to communicate? Or what happens so that from our mobile phone we can control the cameras to access home when we are on the beach, we can vary the intensity of the light in our room or turn on the heating before we get home from our skiing holidays?
Without a doubt, the first thing we’ll think about is that if the devices understand the commands I send you from the console or from your mobile phone, these devices and mobiles must speak the same language. That’s right! this “common language” spoken by the devices is called Protocol.
Now comes the next question: What the hell is a protocol? The truth is that we can say that since the popularization of information technology and, above all, the Internet, the term Protocol has been widely heard. But on many occasions I think it is a term, like so many others, that we know we use, that we are aware that it has to do with computer science, but we have no idea what it is for or what it is for.
My aim will be to come up with a clear definition of what a Protocol is in an understandable way and in a sentence and what the Communications Layers are for which this Protocol moves as if it were in its own home…
Of the different definitions of Protocol that we can find, the one that I like the most is the following one for its simplicity and clarity:”Set of rules that allow communication between computers” (Wikipedia). Clearly between Norms we refer to Syntax, Semantics, Synchronization and error recovery. We go all those things that need two people who want to communicate to understand each other.
We can say without fear of making a mistake that two digital devices (persons) who speak different protocols (languages) will never be able to communicate.
Now that we know what a protocol is. Let’s see how they make these protocols to go from one place to another. Because this was a big problem in the 1980s with the expansion of communications networks due to proprietary connections. That is, packet communications technology grew and grew and each company drew a series of rules and communication criteria that allowed their devices to understand each other, but if they left their environment were no longer understood with anyone, due to the CopyRight of this proprietary connection technology. It is as if we put walls on our borders and refuse to communicate with the rest of the countries. Obviously we understand each other well with the one who is inside but we can’t go anywhere else… nobody would understand us and we would feel “weirdos”.
Due to the problems that were causing these Proprietary Connections the ISO (International Organization for Standardization) met and said… Here we have to do something so that all these connections can be compatible. They analyzed some of the most advanced network technologies of the moment and established the OSI (Open System Interconection) Model. This model is the one that will define the different Levels or Layers that all open network interconnection technology must base.
These Levels or Layers will separate the tasks that have to be executed during the transmission of the message from the highest level (application) to the lowest (physical) level. This architecture will allow communication between different types of hardware and software. It represents by all levels that a message must pass through to reach its destination.
Now let’s see which are the seven layers established by the OSI Model, how the TCP/IP model adapts them and like us in our course, we still schematize it a little more to make it more understandable and cover the needs that arise when installing home automation systems in real estate.
OSI Model Layers
OSI vs TCP/IP Model Comparison
Although the OSI model does not itself conform a standard, it does standardize the elements involved in communication between equipment from different manufacturers.
The layers are read from bottom to top. The Physical Layer being number 1 and the Application layer 7.