ISO/OSI Layer Model
The ISO/OSI (International Organization for Standardization/Open Systems Interconnection) layer model is a conceptual model used to understand how different parts of network communication systems interact with each other. It consists of seven layers, each with its own specific function.
This is what it looks like:
Overview of the Seven Layers
| Layer | Name | Description |
|---|---|---|
| Layer 1 | Physical Layer | Handles the physical connection between devices and the transmission of raw data bits over a medium. Defines specifications like voltage levels, cable types, and data rates. |
| Layer 2 | Data Link Layer | Provides reliable data transfer across the physical link. Handles framing, error detection, and flow control. Examples: Ethernet, PPP. |
| Layer 3 | Network Layer | Responsible for routing packets across networks. Determines optimal paths using addressing and routing protocols. Example: IP. |
| Layer 4 | Transport Layer | Ensures reliable, transparent data transfer between end systems. Handles segmentation, sequencing, and error recovery. Examples: TCP, UDP. |
| Layer 5 | Session Layer | Manages sessions between applications. Establishes, maintains, and terminates communication sessions. |
| Layer 6 | Presentation Layer | Ensures data is in a readable format for the receiving application. Handles translation, encryption, and compression. |
| Layer 7 | Application Layer | Provides an interface between the network and the application software. Examples: HTTP, SMTP, FTP. |
Summary
Each layer of the OSI model serves as a building block, with each one contributing functionalities that collectively enable the smooth exchange of data between devices across a network.
As information travels through these layers, it undergoes a series of transformations, encapsulations, and validations, ensuring data integrity, reliability, and efficiency throughout the communication process. Through their coordinated efforts, the OSI layers establish a standardized framework that enables interoperability, scalability, and robustness within networked environments, allowing seamless communication and interaction between devices and applications.