Networking Basics: The OSI Model

The OSI model is a conceptual framework for networking protocols, dividing network architecture into 7 layers.

The OSI model is divided into 7 layers that handle different aspects of data communication.

The lower layers deal with physical signals, data transmission, and routing.

Higher layers handle network requests, data representation, and user-facing protocols.

The lowest layer of the OSI model, responsible for transmitting data bits over network media.

The OSI model, though less frequently implemented directly in networking, is used as a conceptual tool for learning and troubleshooting.

Understanding the OSI model can aid in pinpointing network issues to specific layers, simplifying troubleshooting.

The arrangement and design of network elements to enable communication between devices.

The Presentation layer handles data format conversions and encryption/decryption needed by the Application layer.

The Application layer provides network services to user applications, like web browsing.

HTTP (HyperText Transfer Protocol) manages data for web pages.

A tool that selects web server, contacts it, requests files, shows web page files.

Handles various image, audio, and HTML formats.

Layer 7 gives data to Layer 6, which gets data from Layer 7 in the OSI model

This layer handles data transmission using signals (electric, radio etc.) over the physical medium.

Internet Explorer or Netscape are applications allowing computer access to web pages.

This layer checks for errors, packages bits into frames, and controls access to the physical medium (e.g., MAC addresses).

Provides network services and protocols for user data in network application contexts.

This layer determines the best path for data packets (routing) from source to destination using logical addresses (e.g. IP).

The network layer uses logical addresses (like IP addresses) for devices, and handles mapping between logical and physical addresses.

This layer delivers data over network connections. Error recovery and flow control are possible depending on the protocol.

The session layer manages network connections (establishing and closing them).

The data link layer is split into two parts: Media Access Control(MAC) and Logical Link Control(LLC).

The network layer packages data into packets for delivery to the transport layer.

A protocol that allows computers to communicate over the internet.

A protocol that finds the physical MAC address of a device from its IP address.

The device that acts as an intermediary to route data to the internet.

Layer that prepares data for transmission using MAC addresses.

Layer responsible for physical transmission of data.

Converts data formats between the application and the network.

Requests web pages, displays them, and handles connections to servers.

A reliable connection used to send data across the network in chunks.

Manages individual communication sessions between a web browser and server.

Handles reliable data delivery by numbering and reassembling data chunks.

Determines the best route for data packets using addresses to identify computers.

A protocol that manages requests and responses in the application layer for web pages.

A computer that receives requests and sends back web page content.