Introduction to Networking
Welcome to the networking section of the playbook. This section covers the fundamental concepts of networking that are essential for any system or DevOps engineer.
What is a Network?
A network is a collection of interconnected devices, such as computers, servers, and routers, that can exchange data and share resources. The internet is the largest example of a global network.
OSI vs TCP/IP Model
There are two primary models used to describe the layers of a network: the OSI model and the TCP/IP model.
- OSI Model: The Open Systems Interconnection (OSI) model is a conceptual framework that standardizes the functions of a telecommunication or computing system into seven distinct layers. It is a theoretical model that is often used for teaching and understanding network concepts.
- TCP/IP Model: The TCP/IP model is a more practical model that is used in the real world. It consists of four layers: Application, Transport, Internet, and Network Access.
| OSI Model Layer | TCP/IP Model Layer | Description |
|---|---|---|
| 7. Application | Application | Provides network services to applications |
| 6. Presentation | Application | Translates, encrypts, and compresses data |
| 5. Session | Application | Establishes, manages, and terminates connections |
| 4. Transport | Transport | Provides reliable data transfer services |
| 3. Network | Internet | Handles addressing and routing of data |
| 2. Data Link | Network Access | Manages error-free data transfer between nodes |
| 1. Physical | Network Access | Defines the physical connection between devices |
Common Network Devices
- Router: A router is a device that connects different networks together and forwards data packets between them.
- Switch: A switch is a device that connects devices within the same network and forwards data packets to the correct device.
- Hub: A hub is a simple device that connects multiple devices together, but it broadcasts all data to all connected devices.
- Firewall: A firewall is a security device that monitors and controls incoming and outgoing network traffic based on predetermined security rules.
- Load Balancer: A load balancer is a device that distributes network traffic across multiple servers to improve performance and reliability.