Working of Open System Interconnection OSI model

Duration: 7 min

This video lesson is available to enrolled students.

Inside: a video lesson and guided study material.

Module outline

Paper 1 | Reasoning Test: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Seating Arrangements, Blood Relations, Puzzle Solving (Puzzles), Venn Diagram, Analogy, Ranking, Order and Sequence, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Selection Decision Table (Decision Making), Logical Sequence Of Words, Cubes & Dices, Analytical Reasoning (Counting Figures Reasoning), Calendar, Alphabet and Word Tests, Numerical Reasoning, Number System, Averages, Mixtures and Alligation, Percentages, Series Completion, Analogy and Classification, Patterns in Two-Dimensional Figures, Coding and Decoding, Mathematical Operations, Direction Sense, Algebra, Logical Deduction and Induction, Syllogisms and Venn Diagrams, Critical Reasoning, Order, Ranking and Sequence, Reading Comprehension, Profit, Loss and Discount, Constraint Puzzles, Speed, Time and Distance, Traverse Surveying, Ratio and Proportion, Time and Work, Mensuration, Permutations and Combinations, Clocks and Calendars, Data Interpretation, Assembling and Grouping of Shapes, Transformation of Shapes, Three-Dimensional Patterns and Visualization, Cubes and Dice, Vocabulary, Blood Relations, Data Sufficiency
Paper 1 | Numerical Analysis: Number System, HCF LCM, Percentage, Ratio and Proportion (Ratios), Average, Sequence and Series (Series), Powers and Exponents (Surds and Indices), Algebra, Statistics, Data Interpretation, Mental Ability, Arithmetic, Logarithm, Profit and Loss, Simple Interest and Compound Interest, Speed Time and Distance, Mixture and Alligation, Mensuration and Geometry, Permutation and Combination, Probability, Sequences and Series, Powers, Surds and Logarithms, Subject-Verb Agreement, Sentence Completion, Geometry, Sentence Structure and Correction, Data Sufficiency, Trigonometry, Measurement and Quantity Take-Off, Signal Space and Optimum Detection, Probability, Statistics, Algebra, Time and Work, Speed, Time and Distance, Data Interpretation, Graph Theory, Combinatorics
Paper 1 | General Knowledge: State Wise GK, History, Geography, GK- Current Affairs, Static General Knowledge, Polity, Indian Economy
Paper 1 | DBMS: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, SQL, Transaction Management, Concurrency Control, Relational Calculus, Database Security & Authorization, Database Recovery
Paper 1 | Data Communication & Network: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP, Application Layer, Network Security, Security in Mobile and Wireless Computing, Input Output Organisation, File Management, Hardware Basics, Terms & Abbreviations, Protocols & Services, Network Access Technologies, Cyber Safety and Security, Basics of COA
Paper 2 | System Analysis & Design: Fundamentals of Systems and Information Systems, SDLC and Development Approaches, Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Documentation and Software Requirements Specification (SRS), SDD and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, Security, Risk Management & Maintenance, extras
Paper 2 | Programming Language (Java): Java Fundamentals, OOPS with Java, Array, String, IO & References, Generic & Collections, Multithreading, Java, Miscellaneous, Control Flow, OOPS with C++, Stack, C Fundamentals, Arrays & Pointers, Object Oriented Technology, Control Flow & Looping, Introduction to Python

AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The lecture introduces the OSI model's layered architecture, defining its seven ordered layers from Physical to Application. It explains vertical service dependencies and horizontal peer-to-peer communication, visually grouping the top three layers as software, the bottom three as hardware, and identifying Transport as the 'heart of OSI'. The core teaching focuses on peer-to-peer processes: data encapsulation where each sending layer adds its own header (AH, PH, SH, TH, NH, DH) to the message from above before passing it down. At Layer 1, the package is converted into a stream of bits for transmission across intermediate nodes to Device B. The receiving device then decapsulates the message layer by layer, unwrapping headers to deliver data back up to the application. Hand-drawn annotations emphasize specific layers and data flow.

Chapters

0:00 – 2:00 00:00-02:00
The instructor presents a slide titled 'Layered Architecture' listing the seven OSI layers. On-screen text states that each layer calls upon the services of the layer just below it, while 'layer x on one machine communicates with layer x on another machine' via peer-to-peer protocols. A diagram appears showing the seven layers stacked vertically, with arrows indicating sender and receiver flow. The visual categorizes the top three layers as 'Software Layers', the bottom three as 'Hardware Layers', and labels the Transport Layer specifically as the 'Heart of OSI'.
2:00 – 5:00 02:00-05:00
The lecture transitions to a slide titled 'Peer-to-Peer Processes', using an animated diagram of Device A and Device B communicating through intermediate nodes. The instructor points to a diagram showing data encapsulation, where each layer adds its own header (AH, PH, SH, TH, NH, DH) to the data as it moves down the stack. The visual progression shows the step-by-step addition of headers, forming a growing package. The instructor explains that at Layer 1 (Physical), the entire package is converted to a stream of bits for transmission, while at the receiving machine, the message is unwrapped layer by layer.
5:00 – 7:08 05:00-07:08
The instructor uses a stylus to draw red circles and arrows around the encapsulation diagram, highlighting headers (SH, TH) being added to data as it moves down the stack. The diagram shows Device A, intermediate nodes, and Device B, with on-screen text identifying 'Peer-to-peer protocol (7th layer)'. The instructor points to the Session and Network layers on both sides of the diagram, emphasizing that communication at the physical layer is direct, while higher layers require data to move down through the sender's stack and back up through the receiver's stack. Bullet points summarize the rules of peer-to-peer communication at different layers.

The lecture systematically builds understanding of the OSI model from its structural definition to its operational mechanics. It begins by establishing the seven-layer hierarchy and their vertical/horizontal relationships, using color-coded groupings (software/hardware/heart) to aid memorization. The central concept is encapsulation: the process where each layer adds its own header to the data from above. This is demonstrated through a step-by-step animated diagram showing headers (AH, PH, SH, TH, NH, DH) being prepended to the data as it travels from Application down to Physical. The physical layer's role in converting this package into a bit stream for transmission is highlighted as the critical transition point. The receiving process (decapsulation) is explained as the reverse, where headers are stripped away layer by layer. Hand-drawn annotations serve to reinforce specific layer interactions and data flow directions, making the abstract concept of peer-to-peer communication visually concrete for students.