OSI Layer - Part 1

The understanding of the OSI(Open System Interconnection) model will always help you to troubleshoot the issues you may face in your applications or dealing with any cloud platform. Cloud is mostly about networking and how the data flows.

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OSI model is a conceptual framework developed by the International Organization for Standardization (ISO) that standardizes networking functions into seven layers to facilitate interoperability between different systems. The best way to understand about networking is using the OSI model.

The OSI layers are the basic building block of any network.

The series will start the movement of data in the local network. It is the starting or ending point of data in the network. Next we will cover routing, and see how data moves from local network to global applications like Netflix or to any cloud provider like AWS.

Next we will cover about the segmenting of data. How data is divided in chunks and carried in the network from source to destination.

There are two parts in the networking stack, Media Layers and Host Layers.

Media layers decide how the data is transmitted from point A to point B. Host layers determine how the data is data is chopped up, transferred and assembled during the transportation.

1. Media Layers (Lower Layers) - Responsible for Data Transmission

These layers deal with physical connectivity, data encoding, and transmission over the network.

1. Physical Layer (Layer 1) – Deals with raw data transmission, electrical signals, cables, and hardware.

2. Data Link Layer (Layer 2) – Handles error detection, MAC addressing, and frame transmission.

3. Network Layer (Layer 3) – Manages routing, IP addressing, and packet forwarding.

2. Host Layers (Upper Layers) - Responsible for Data Processing and Communication

These layers handle end-to-end communication, data formatting, and user interaction.

4. Transport Layer (Layer 4) – Ensures reliable data delivery using protocols like TCP/UDP.

5. Session Layer (Layer 5) – Manages sessions, connections, and authentication.

6. Presentation Layer (Layer 6) – Handles data translation, encryption, and compression.

7. Application Layer (Layer 7) – Interfaces with the user, providing network services like HTTP, FTP, SMTP, etc.

In the coming articles, I will cover up all the layers in details with simple explanation. Stay tuned for next articles.