Polling - Controlled Access Protocol

Duration: 6 min

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Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
  2. Section A: General Awareness: Polity, Physics, Biology, Chemistry, Static General Knowledge, History, Geography, Indian Economy, GK- Current Affairs, Evolution of Indian Banking (Banking & Financial Awareness), Environment
  3. Section A: General Intelligence & Reasoning ability: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Analytical Reasoning (Counting Figures Reasoning), Blood Relations, Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Seating Arrangements, Directions (Direction Test), Puzzle Solving (Puzzles), Calendar, Clock, Cubes & Dices, Selection Decision Table (Decision Making), Logical Sequence Of Words, Crypt Arithmetic, Venn Diagram, Data Arrangement, Inequality, Analogy, Ranking, Order and Sequence, TCS NQT Advanced Reasoning Ability
  4. Section A: Arithmetical & Numerical Ability: Ratio and Proportion (Ratios), Divisibility Rules, Data Interpretation, Mixture and Alligation, Permutation and Combination, Logarithm, Number System, HCF LCM, Sequence and Series (Series), Speed Time and Distance, Percentage, Average, Profit and Loss, Simple Interest and Compound Interest, Time and Work, Pipe and Cistern, Mensuration and Geometry, Powers and Exponents (Surds and Indices), Algebra, Probability, Mental Ability, Age Problems, Partnership, Statistics, Arithmetic, Speed Mathematics and Basic Mathematics, Miscellaneous
  5. Section A: English Language & Comprehension: Vocabulary, Subject Verb Agreement (Verb Noun Agreement), Adjectives, Tenses, Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Articles, Sentence Construction, Preposition, Direct and Indirect Speech, Sentence Completion (Fill in the blanks), Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Modals, Active Passive Voice (Voice), Sentence Correction (Error Correction), Adverb, Conjunction, Cloze Test (Cloze Passage)
  6. Section A: Hindi Language & Comprehension: भाषा, लिपि, ध्वनि, वर्ण, अक्षर, स्वर, व्यंजन, मात्रा और संयुक्ताक्षर, वर्तनी, वर्ण-विन्यास, अनुस्वार, अनुनासिक, चंद्रबिंदु और ‘र’ के रूप, शब्द, पद और शब्द-भेद, संज्ञा और सर्वनाम, विशेषण और क्रिया, लिंग, वचन, पुरुष और कारक, काल, वाच्य, वाक्य और वाक्य-भेद, संधि, समास, विलोम शब्द, पर्यायवाची शब्द, सामान्य अशुद्धियाँ, अनेक शब्दों के लिए एक शब्द, मुहावरे और लोकोक्तियाँ, अपठित गद्यांश और अपठित पद्यांश, Multi-Topic Content (Cross-Concept Material), वर्णमाला
  7. Section B: Programming, Data Structures, OOP & Java: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Java, OOPS with C++, Language Design, Intro to Compilers, Visual Basics, Syntax Analysis: Bottom-Up, Object Oriented Technology
  8. Section B: Computer Networks, TCP/IP & Network Security: Introduction to CN, Data Communication, DLL: Flow Control, DLL: Access Control, DLL: Error Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics, Network Access Technologies, Network Security, Society, Law & Ethics, Mobile Computing, Net Layer:Routing Protocol, Cyber Safety and Security
  9. Section B: Teaching Methodology: Child Development, Concept of Pedagogy, Theories, Inclusive Education, Experiential Pedagogy, Assessment & Evaluation, Curriculum Framework & Reforms, National Education Policy (NEP) 2020, Psychology, Teaching-Learning Process, Personality Development, Teaching Methods & Strategies, Learning and Motivation, Learners & Learning Process, Factors Affecting Teaching, Methods of Teaching, Nature, Objectives & Characteristics of Teaching, Teaching-Learning Aids & ICT Integration, Classroom Management & Communication, Evaluation, Assessment & Measurement, Curriculum & School Environment, Inclusive Education & Special Needs, Professional Development & Ethics
  10. Section B: Digital Electronics / Boolean Logic: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Analog-Digital Conversion
  11. Section B: Operating Systems & Linux: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, File Management, Disc Scheduling, Unix OS, Linux OS, Distributed Systems, Windows OS
  12. Section B: Data Base Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, Relational Algebra, SQL, File Organization & Indexing, Transaction Management, Concurrency Control, Database Security & Authorization, Database Recovery, Data Warehousing & Mining
  13. Section B: Internet & Web Technologies: Website, Browser & Services, Internet Fundamentals, Web Design & Development, Protocols & Services, Web Publishing & Hosting, Server Side & Security, HTML Basics, CSS, Emerging Technologies, JavaScript-Basics, .Net Programming, Electronic Data Interchange and E-Commerce, XML
  14. Section B: Computer Fundamentals, IT Basics & Architecture: Basics of COA, Cache Memory Organization, Input Output Organisation, Register Transfer and Microoperations, Control Unit Design, Programming the Basic Computer, Terms & Abbreviations, MS Office Applications, Instr Formats & Modes, Floating Point Rep
  15. Section B: Python Language: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis
  16. Section B: Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, extras, Fundamentals of Systems and Information Systems
  17. Section B: Design & Analysis of Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  18. Section B: Mathematics: Linear Algebra, Calculus, Trigonometry, Vectors, Set Theory, Functions, Relations, Propositional and Predicate Logic, Research Process Steps, Graph Theory
  19. Section B: Computer Graphics, Multimedia & Mobile Computing: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, 3-D Object Representation, Geometric Transformations and Viewing, Multimedia
  20. Section B: Emerging Trends: Emerging Tech Trends, Knowledge Representation, Natural Language Processing
  21. DSSSB Previous Year Paper:
  22. Business Studies and Management: Business Communication, Business Organization and Management, Financial Accounting, Business Economics, Management Information System (MIS), Knowledge Management & New Economy
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This lecture introduces Polling, a controlled access protocol used in network communications where a primary station manages multiple secondary stations. The instructor explains that all data exchanges must pass through the primary device, which controls the link and dictates when secondary devices can transmit. The core concepts covered include the distinction between 'Select' and 'Poll' functions, illustrated through sequence diagrams showing message exchanges like SEL (Select), ACK (Acknowledgment), Data frames, and NAK (Negative Acknowledgment). The teaching flow progresses from defining the network topology to detailing specific operational mechanisms, emphasizing that the primary device solicits transmissions in turn. Key evidence includes on-screen text stating 'The primary device controls the link' and diagrams visualizing five-step interactions for data transfer. The lecture highlights that if a secondary device has no data, it responds with a NAK, whereas the Select function is used when the primary initiates sending data to a specific secondary.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The lecture begins with an introduction to Polling as a controlled access protocol. The slide titled 'Polling' defines the system architecture involving one primary station and multiple secondary stations where all data exchanges pass through the primary device. Visible text emphasizes that 'The primary device controls the link; the secondary devices follow its instructions.' Two sequence diagrams labeled 'Select' and 'Poll' are displayed to illustrate communication flows between a Primary server and secondary devices A and B. The instructor gestures toward these diagrams to demonstrate how the primary device controls the link and determines which secondary station is allowed to use the channel. This section establishes the foundational topology where the primary manages communication, ensuring orderly access to the shared medium.

  2. 2:00 – 5:00 02:00-05:00

    The instructor details the polling mechanism where a primary station manages communication by soliciting transmissions from secondary devices in turn. The slide explains that the 'poll function is used by the primary device to solicit transmissions from the secondary devices.' If a secondary has data, it responds with a Data frame; otherwise, it sends a NAK (Negative Acknowledgment). The visual diagrams contrast the 'Select' function, where the primary initiates data transfer to a specific secondary using SEL and ACK frames, with the 'Poll' function used for receiving data. The instructor points a pen at secondary station 'A' in the left diagram to clarify the interaction sequence. This segment clarifies that polling is a request-response mechanism where the primary actively queries each device to check for pending data, ensuring controlled access without collisions.

  3. 5:00 – 6:29 05:00-06:29

    The final segment focuses on the 'Select' function, explaining that it is used whenever the primary device has something to send. The text states, 'The select function is used whenever the primary device has something to send,' and notes that the primary must alert the secondary before transmission. Two sequence diagrams visualize this process, showing message frames like SEL, ACK, Data, Poll, and NAK exchanged between a Primary server and secondary devices A and B. The instructor stands beside the screen, gesturing toward the 'Select' diagram which outlines a five-step interaction starting with a SEL frame. This section concludes by reinforcing that the primary device initiates data transfer to specific secondaries, contrasting with polling where the secondary responds only when queried.

The lecture systematically explains Polling as a controlled access protocol where a primary station manages multiple secondary stations. The central idea is that the primary device controls the link, and all data exchanges must pass through it. The instructor distinguishes between two key functions: 'Select' and 'Poll'. Select is used when the primary has data to send, initiating a five-step handshake involving SEL and ACK frames. Poll is used when the primary wants to receive data, soliciting responses from secondaries in turn; a secondary responds with Data if it has information or NAK if it does not. The sequence diagrams provide concrete evidence of these interactions, showing message exchanges between Primary and secondary devices A and B. This protocol ensures orderly communication by preventing collisions through centralized control.

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