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The OSI (Open Systems Interconnection) model is a framework used to understand how data moves across a network. It divides network communication into 7 layers, each with a specific function. The 7 Layers of OSI Model (Bottom to Top) Layer 1 – Physical Layer Deals with actual hardware and transmission of raw bits (0s and 1s). Cables, switches, hubs Defines how devices are physically connected and how bits are transmitted. Layer 2 – Data Link Layer Responsible for node-to-node communication and error detection. Uses MAC addresses to identify devices on the same network. Switches, bridges. Ethernet, PPP, VLAN. Layer 3 – Network Layer Handles routing and logical addressing (IP addresses). Determines the best path for data between devices across networks. Routers. IP, ICMP, OSPF, BGP. Layer 4 – Transport Layer Ensures reliable data delivery and error recovery. Uses ports to direct data to the correct application. TCP (reliable), UDP (fast, unreliable). Segmentation, flow control, error checking. Layer 5 – Session Layer Manages sessions or connections between devices. Handles starting, maintaining, and ending communication sessions. NFS, SQL, RPC. Layer 6 – Presentation Layer Translates data into a format that the application can understand. Handles encryption, decryption, compression. SSL/TLS, JPEG, MPEG, ASCII. Layer 7 – Application Layer Closest to the end-user; provides network services to applications. HTTP, HTTPS, FTP, SMTP, DNS. Allows users and software to interact with the network.

💡 OSI 7 Layers Model ✅ Physical Layer (Layer 1) Deals with hardware transmission of raw data bits over physical media (cables, fiber, radio waves). Defines connectors, voltage levels, frequencies, and data rates. 🔵Examples: Ethernet cables, Fiber optics, Hubs. ✅Data Link Layer (Layer 2) Provides error detection and framing for reliable node-to-node data transfer. Uses MAC addresses for device identification in the same network. 🔵Examples: Switches, Ethernet, Wi-Fi (802.11). ✅Network Layer (Layer 3) Responsible for logical addressing, routing, and forwarding of data packets across networks. Uses IP addresses. 🔵Examples: Routers, IP (IPv4/IPv6), ICMP. ✅Transport Layer (Layer 4) Ensures end-to-end communication, error recovery, and data segmentation. Uses ports to identify applications. 🔵Examples: TCP (reliable, connection-oriented), UDP (fast, connectionless). ✅Session Layer (Layer 5) Manages sessions (connections) between applications. Handles authentication, authorization, and session recovery. 🔵Example: NetBIOS, Remote Procedure Call (RPC). ✅Presentation Layer (Layer 6) Translates, encrypts, and compresses data for the application layer. Ensures compatibility between different systems. 🔵Examples: SSL/TLS (encryption), JPEG, GIF, MPEG. ✅Application Layer (Layer 7) Closest to the end user. Provides services and interfaces for applications to communicate over a network. 🔵Examples: HTTP/HTTPS (web), FTP, SMTP (email), DNS. ✅ In short: Layer 1–2: Data delivery in the same network (hardware & LAN). Layer 3–4: Data delivery between networks (IP & ports). Layer 5–7: User interaction, data representation, and application communication.

Understanding the OSI Model in Simple Terms The OSI Model (Open Systems Interconnection Model) is a framework that describes how data travels from one device to another across a network. It breaks the communication process into seven layers each with its own role. Layer 7 – Application This is where you and I interact with the network email web browsing file transfers and so on. Think of protocols like HTTP FTP or DNS. Layer 6 – Presentation This layer makes sure the data is in a usable format. It handles translation compression and encryption such as SSL TLS or data formats like JPEG. Layer 5 – Session Here the system manages sessions creating maintaining and ending the dialogue between two applications. Layer 4 – Transport Responsible for reliable delivery of data. It chops data into segments manages error checking and flow control. Protocols like TCP and UDP live here. Layer 3 – Network This layer decides how data gets from point A to point B using logical addressing and routing IP ICMP routers. Layer 2 – Data Link Handles node-to-node delivery framing and error detection. Technologies like Ethernet MAC addresses and switches work at this level. Layer 1 – Physical The actual physical transmission cables connectors signals voltages. Without this nothing else can happen. An easy way to remember the order from top to bottom is All People Seem To Need Data Processing (Application, Presentation, Session, Transport, Network, Data Link, Physical) Understanding the OSI Model helps you troubleshoot networks design systems and see where different technologies fit into the bigger picture.

🚀✅Understanding the OSI Model in Networking The OSI (Open Systems Interconnection) model is a crucial framework for understanding and troubleshooting network systems. It breaks down the complex process of data transmission into 7 distinct layers, from physical transmission all the way to the application layer. 🌐 Here’s a breakdown of the OSI layers: 1️⃣ Physical - Media, signal, and binary transmission (Ethernet, RS-232, DSL, etc.) 2️⃣ Data Link - Addressing, error detection, and flow control (Ethernet, MAC addresses) 3️⃣ Network - Logical addressing, routing, and path determination (IP, ARP, OSPF) 4️⃣ Transport - End-to-end connection reliability and flow control (TCP, UDP, SSL/TLS) 5️⃣ Session - Session management and communication (TCP, SIP, RPC) 6️⃣ Presentation - Data representation and encryption (HTML, JPEG, MP3) 7️⃣ Application - Network services like email, web browsing, and file transfer (HTTP, FTP, SMTP) This model helps IT professionals manage network communications effectively and ensure smooth data flow across systems. 🛠️📊.

🔹 What is the OSI Model? The OSI (Open Systems Interconnection) model, developed by ISO in 1984, is a reference framework that explains how data is transmitted between computers. It consists of 7 layers, each with a specialized role in networking: 1️⃣ Physical Layer – Transmits raw bits over a physical medium 2️⃣ Data Link Layer – Ensures node-to-node data transfer and error detection 3️⃣ Network Layer – Handles addressing and routing of packets across networks 4️⃣ Transport Layer – Ensures reliable end-to-end data delivery with flow/error control 5️⃣ Session Layer – Manages, establishes, and terminates communication sessions 6️⃣ Presentation Layer – Translates, encrypts, and formats data for applications 7️⃣ Application Layer – Interfaces with end-user applications (e.g., email, web, file transfer) 🔹 What is the TCP/IP Model? The TCP/IP model (Internet Protocol Suite) is a more practical and simplified version of the OSI model, used as the foundation for modern internet communication. It has 4 layers: 1️⃣ Link Layer – Manages physical connections & framing (Ethernet, PPP) 2️⃣ Internet Layer – Handles IP addressing and packet forwarding (IP protocol) 3️⃣ Transport Layer – Provides host-to-host communication (TCP for reliable, UDP for fast connectionless) 4️⃣ Application Layer – Supports application-level protocols (HTTP, DNS, FTP, SMTP)

If Episode 1 answered “What is Networking ?”, today we go one step deeper into the blueprint of all digital communication : the OSI Model The Open Systems Interconnection (OSI) Model breaks networking into 7 logical layers, each with a specific role in moving data from one device to another Here’s a quick breakdown : 1️⃣ Physical : cables, signals, Wi-Fi waves 2️⃣ Data Link : MAC addresses, Ethernet, local delivery 3️⃣ Network : IP addresses, routing across networks 4️⃣ Transport : TCP/UDP, reliable delivery, ports 5️⃣ Session : manages connections (start, maintain, end) 6️⃣ Presentation : data format, compression, encryption 7️⃣ Application : user-facing services like HTTP, DNS, email 💡 Analogy : Think of it like sending a letter Layer 1 = the road the mail truck drives on Layer 2 = the house number Layer 3 = the city map Layer 4 = registered mail vs. postcard Layer 5 = keeping the phone line open Layer 6 = translating the language Layer 7 = the actual message you write The OSI Model helps engineers troubleshoot systematically : Cable issue ? Check Layer 1 Wrong IP ? Look at Layer 3 App not working ? Go to Layer 7 #Networking #NetworkingFundamentals #BackToSchool #IT #ComputerNetworks

Day 5/365 – Basic Understanding Of OSI Model The OSI (Open Systems Interconnection) Model is a conceptual framework that defines how data is transmitted and received over a network. It divides communication into seven layers, where each layer has its own function but works together to ensure smooth and reliable data exchange. 🔹 1. Physical Layer – Manages the physical connection (cables, switches, signals). 🔹 2. Data Link Layer – Ensures error-free delivery between directly connected devices (MAC addresses). 🔹 3. Network Layer – Handles logical addressing & routing (IP addresses, routers). 🔹 4. Transport Layer – Provides reliable end-to-end delivery (TCP/UDP, error correction). 🔹 5. Session Layer – Establishes, maintains, and ends sessions between devices. 🔹 6. Presentation Layer – Translates data formats, encrypts, and compresses information. 🔹 7. Application Layer – Closest to the user; apps like browsers, emails, and messengers run here. Why it matters? The OSI Model is not just theoretical—it’s a foundation for designing, understanding, and troubleshooting networks. By breaking communication into layers, it helps IT professionals identify exactly where issues occur. #Networking #OSIModel #Day5of365 #ComputerScience #NetworkingBasics #LearningJourney

SNMP is commonly used for network monitoring... But is model driven telemetry better? SNMP has been the de facto standard for network monitoring for over 34 years. SNMP: → pull-based (only gets device info when queried) → frequent polling can add strain to your network → difficult to provide "real-time" responses But as network deployments grow, and traffic needs increase - SNMP polling has trouble scaling. Model driven telemetry is a newer approach that is becoming the preferred method for monitoring. Model driven telemetry: → reduces bandwidth and CPU overhead → very efficient to send to multiple recipients → data can be sent periodically or on an event trigger → push model (data flows continuously to subscribers) As more devices support telemetry it's becoming more practical to use across your network. Overall, telemetry gives you more data, with better performance. P.S. Have you tried using model driven telemetry? What do you think?

🚀Differences between TCP IP and OSI 🚀 TCP/IP and OSI models are both fundamental frameworks for understanding network communications, but they differ significantly in structure, purpose, implementation, and design philosophy. 🫵OSI Model designed By ISO (International Standard Organization). 🫵TCP/IP designed by DARPA/ARPANET. Key Differences 1. Number of Layers: The OSI model has 7 layers (Physical, Data Link, Network, Transport, Session, Presentation, Application) while the TCP/IP model has 4 layers (Network Access, Internet, Transport, Application). 2. Development and Purpose: OSI is a conceptual, protocol-independent framework created for standardization and teaching. TCP/IP is a practical, protocol-driven suite used as the basis for real-world Internet communication. 3. Layer Functions: OSI keeps Presentation and Session layers distinct, while TCP/IP folds their functions into its Application layer. TCP/IP’s bottom layer merges OSI’s Physical and Data Link layers. 4. Approach: OSI follows a strictly layered, vertical approach, with clear boundaries and independent layers. TCP/IP uses a looser, horizontal approach with more inter-layer interaction. 5. Protocol Dependency: OSI is protocol-agnostic and not tied to specific network protocols. TCP/IP is protocol-dependent, defining the real protocols used across the Internet. 6. Implementation: TCP/IP is widely used in practical networking, especially the Internet, while the OSI model is mostly an educational reference. 7. Reliability & Services: OSI can offer both connection-oriented and connection less services at the network layer; TCP/IP’s network layer mainly provides connectionless service. These differences make OSI more suitable for learning and network design, while TCP/IP is essential for real-world networking and Internet protocols #Networking #Telecommunication #Connections #TCP/IP #OSI