OSI Layer 1 physical standards

What are the OSI Layer 1 physical standards?

The OSI (Open Systems Interconnection) model is a conceptual framework used to understand and standardize the functions of a telecommunications or computing system without regard to its underlying internal structure and technology. Its goal is the interoperability of diverse communication systems with standard protocols. The model is divided into seven layers, with Layer 1 being the Physical Layer.

The Physical Layer defines the electrical and physical specifications for devices. In particular, it defines:

• Physical media types: The types of cables (such as coaxial, fiber optic, twisted pair) and wireless technologies that carry the signal between devices.
• Connector types: The types of connectors used to connect cables to devices, ensuring that the physical connection is established properly.
• Signal types: The type of signal used to transmit data, which can be electrical, optical, or radio signals, depending on the medium.
• Data rate: The rate at which data can be transmitted, measured in bits per second (bps).
• Modulation techniques: Methods used to convert digital data into signals that can be transmitted over the physical medium.
• Bit synchronization: Techniques for ensuring that the sender and receiver are synchronized at the bit level, enabling the correct interpretation of the data stream.

Specific standards within the Physical Layer are numerous and can vary based on the network type (such as Ethernet, Wi-Fi, Fiber, etc.). For example:

• Ethernet (IEEE 802.3): Defines standards for wired networking, including various forms of twisted pair and fiber optic cables, with different versions supporting speeds from 10 Mbps to 100 Gbps and beyond.
• Wi-Fi (IEEE 802.11): Defines standards for wireless networking, including radio frequency, signal modulation techniques, and antenna types, with different versions supporting varying speeds and frequencies (2.4 GHz, 5 GHz, etc.).
• Fiber Optics (such as ITU-T G.652): Defines standards for fiber optic cables, including core diameter, modal dispersion, and wavelength, for long-distance and high-bandwidth connections.

Each of these standards specifies the requirements for the physical layer of networks that use that technology, ensuring compatibility and interoperability between different devices and systems.