The OSI model is a conceptual framework that is used to describe how a network functions. It identifies seven fundamental networking layers, from the physical hardware up to high-level software applications.
Each layer in the model handles a specific networking function. The standard helps administrators to visualize networks, isolate problems, and understand the use cases for new technologies.
| Layer | Name | Function |
|---|---|---|
| 7 | Application | Provides services to user applications, such as web browsers, email clients, file transfer programs, etc. For example, HTTP/HTTPS, SMTP, FTP, and DNS. |
| 6 | Presentation | Translates data into a format that can be understood by the application layer. Handles encryption, compression, and character encoding. For example, SSL, SCP, and NetBIOS. |
| 5 | Session | Establishes, maintains, and terminates sessions between nodes. Manages authentication and authorization. For example, RPC and NFS. |
| 4 | Transport | Provides reliable data transfer between nodes. Handles error detection, correction, and flow control. Uses protocols such as TCP and UDP. |
| 3 | Network | Routes data packets across different networks. Handles addressing and routing. Uses protocols such as IP and ICMP. |
| 2 | Data Link | Communicates between nodes that are directly connected in the same network. Handles frame synchronization and error detection. Uses protocols such as Ethernet and WiFi. |
| 1 | Physical | Transfers data as a stream of bits over a physical medium, such as a cable or wireless signal. Handles electrical signals and bit encoding. For example, Bluetooth, USB, DSL, and GSM. |
IT Wonder Lab tutorials are based on the diverse experience of Javier Ruiz, who founded and bootstrapped a SaaS company in the energy sector. His company, later acquired by a NASDAQ traded company, managed over €2 billion per year of electricity for prominent energy producers across Europe and America. Javier has over 25 years of experience in building and managing IT companies, developing cloud infrastructure, leading cross-functional teams, and transitioning his own company from on-premises, consulting, and custom software development to a successful SaaS model that scaled globally.