In computer networking, a core model to understand is the OSI model.
The conceptual OSI or Open Sources Interconnection model describes a series of seven communication layers.
Each layer has its functionality and features.
The OSI model doesnt proscribe any specific protocol.
Instead, it defines a standard communication framework around which protocols can be designed.
Despite this, it remains a good starting place to understand networking concepts.
The physical layer is the fundamental communication platform.
Contents
Whats at the Core of the Physical Layer?
At the core of any physical layer, the standard needs to be a reliable transmission media.
Depending on the standard, this could be an electrical or electromagnetic system.
Theoretically, other communications media are possible, such as audio.
The vast majority of systems use electrical or electromagnetic media, though.
This is due to the transmission speed, range, and high signaling frequencies they offer.
As a case in point, a communication system could be designed to use humans waving flags to communicate.
Functionality is further limited by line of sight, restricting range, especially in non-open environments.
Its also necessary to standardize how theyre arranged (I.e., twisted pairs, shielding, etc.).
The physical connectors need to be designed, both the electrically female and male connectors.
Standard voltage levels must be defined, as do the signaling methods, timings, and acceptable signal-to-noise ratios.
Most of these affect the final bandwidth of the physical connection.
For wireless systems, the design choices are related but different.
The exact frequency or frequencies of light to be used must be standardized.
The precise method of encoding the data in the light must be standardized.
If a fibreoptic cable is to be used, that must be standardized too.
There are many more similarities to standardizing wired connections.
How Does the Physical Layer Interact with the Other Layers?
These chips are generally referred to as PHY chips.
The physical layer doesnt need to be aware of that.
Conclusion
The physical layer is layer one in the OSI model.
It covers the standards for actually transmitting data from one place to another.
