Polling - Controlled Access Protocol

Duration: 6 min

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Module outline

  1. General Intelligence & Reasoning: Analogy, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Blood Relations, Directions (Direction Test), Ranking, Order and Sequence, Logical Sequence Of Words, Syllogisms, Venn Diagram, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Selection Decision Table (Decision Making), Data Sufficiency, Puzzle Solving (Puzzles), Data Arrangement, Cubes & Dices, Calendar, Clock, Arithmetic, Number System, HCF LCM, Verbal Analogy (Word Based Analogy), Visual Recognition and Figure Completion, Paper Folding and Cutting, Transformation of Shapes, Clocks and Calendars, Direction Sense, Cubes and Dice, Patterns in Two-Dimensional Figures, Seating Arrangements, Analogy and Classification, Logical Deduction and Induction, Alphabet and Word Tests, Mathematical Operations, Series Completion, Simplification and Approximation, Coding and Decoding, Numerical Reasoning, Assembling and Grouping of Shapes, Three-Dimensional Patterns and Visualization, Vocabulary, Number System, Averages, Mixtures and Alligation, Simple and Compound Interest, Percentages, Algebra, Speed, Time and Distance, Seating and Arrangement Puzzles, Traverse Surveying, Order, Ranking and Sequence, Constraint Puzzles, Syllogisms and Venn Diagrams, Reading Comprehension, Critical Reasoning, Permutations and Combinations, Narrative Sequencing, Project Monitoring, Resources and Safety, Profit, Loss and Discount, Ratio and Proportion, Time and Work, Mensuration, Data Interpretation, Powers, Surds and Logarithms, Sequences and Series, Articles and Determiners, Sentence Completion, Data Sufficiency, Blood Relations, Simple Interest and Compound Interest, Mixture and Alligation, Sequence and Series (Series), Speed Time and Distance, Algebra, Profit and Loss, Powers and Exponents (Surds and Indices), Permutation and Combination
  2. General Awareness: Physics, Chemistry, Biology, History, Geography, Polity, Indian Economy, Environment, Static General Knowledge, GK- Current Affairs, Artificial Intelligence, MS Office Applications, Terms & Abbreviations, Keyboard Shortcuts, Evolution of Indian Banking (Banking & Financial Awareness), Emerging Tech Trends
  3. Engineering Mathematics: Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic, Linear Algebra, Calculus, Probability, Statistics, Signal Space and Optimum Detection, Probability, Statistics
  4. Digital Logic: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Floating Point Rep, Number Systems and Codes, Registers and Counters, Boolean Algebra and Logic Gates, Microprocessors and Microcontrollers, Logic Families and CMOS Logic, Microprocessors, Logic Gates and Boolean Algebra, Minimization of Boolean Functions, Timing, Hazards and Testing, Logic Families, Combinational Logic Design, Arithmetic Circuits, Waveform Generators and Timer Circuits, Semiconductor Memories and Programmable Logic Devices, Combinational Logic Circuits, Latches and Flip-Flops, Finite State Machines, Sequential Circuits and State Machines, Minimization of Boolean Functions, Arithmetic Circuits, Latches and Flip-Flops, Number Systems and Codes, Registers and Counters
  5. Computer Organisation & Architecture: Basics of COA, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Control Unit Design, Programming the Basic Computer, Register Transfer and Microoperations, Semiconductor Memories and Programmable Logic, Processor Organization and Instructions, Memory Hierarchy and Input/Output, Registers and Counters
  6. Programming & Data Structures: 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, HTML Basics, OOPS with C++, Java, Object Oriented Technology
  7. Databases: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, SQL, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, Database Security & Authorization
  8. Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos
  9. Theory of Computation: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Moore & Mealy Machines, Pushdown Automata & CFG, Turing Machines, Complexity Theory
  10. Compiler Design: Intro to Compilers, Lexical Analysis, Grammar & CFG, Syntax Analysis: Top-Down, Syntax Analysis: Bottom-Up, Semantic Analysis & SDT, Intermediate Code Gen, Code Optimization, Run Time Environment
  11. Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Security, Windows OS, Distributed Systems, Unix OS, Linux OS
  12. Computer Networks: Introduction to CN, 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, Hardware Basics, Data Communication, Website, Browser & Services, Web Design & Development, Network Security, Cyber Threats and Malware Attacks, Cyber Safety and Security
  13. Full Length Mock Tests:
  14. Sectional Tests:
  15. Paper 2 - Full-length Mock Tests:
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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