Understanding the OSI Model: Exploring Its 7 Layers
OSI: Open Systems Interconnection
This model is a reference model that describes how application interact with each other over a computer network. There has 7 layers
Physical Layer
The Physical Layer is responsible for the actual transmission of raw data bits over physical media, such as cables, fiber optics, or wireless signals. It defines the hardware elements involved, like network interfaces and connectors.
For example, Ethernet cables and Wi-Fi are technologies at this layer.
Data Link Layer
The Data Link Layer ensures reliable data transfer between two directly connected nodes. It organizes data into frames and handles error detection and correction. A common protocol at this layer is Ethernet, which governs how devices communicate within the same network.
Network Layer
The Network Layer is responsible for routing data packets across multiple networks. It determines the best path to transfer data to its destination. IP (Internet Protocol) is a key protocol in this layer, helping devices identify and communicate across networks, including the internet.
Transport Layer
The Transport Layer ensures reliable data transfer between two devices over the network. It manages flow control, error correction, and retransmission of lost packets. TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) are common protocols in this layer, with TCP ensuring reliable delivery.
Session Layer
The Session Layer manages and controls the dialogue between two devices, ensuring that data exchanges happen in an organized manner. It establishes, maintains, and terminates sessions. For example, during a video call, the session layer ensures both parties are in sync.
Presentation Layer
The Presentation Layer is responsible for translating data into a format that can be understood by the application. It handles encryption, compression, and translation between different data formats. For example, it might convert data from a .jpg file to a viewable image on your screen.
Application Layer
The Application Layer is the topmost layer and interacts directly with end-user applications. It provides services such as email, file transfers, and web browsing. HTTP (Hypertext Transfer Protocol) and FTP (File Transfer Protocol) are examples of protocols at this layer, enabling communication between web servers and browsers.