Performance of Stop and Wait Protocol - ARQ

Duration: 11 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:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This lecture segment focuses on measuring the performance of the Stop and Wait protocol by deriving a simplified formula for total time. The instructor begins with a comprehensive expression that includes transmission, propagation, queuing, and processing delays for both data and acknowledgment packets. Through a series of standard assumptions—setting queuing and processing delays to zero, treating the acknowledgment transmission time as negligible due to its small size, and equating data and acknowledgment propagation times—the formula is reduced to Total Time = Tt(data) + 2*Tp. The term 2*Tp is explicitly identified as the Round Trip Time (RTT). A hand-drawn diagram on the right side of the slide illustrates the sender-receiver interaction with vertical lines labeled S and R connected by diagonal arrows forming a triangle. The instructor then introduces a numerical example involving a 1 Mbps link, writing calculations for transmission time using the L/B formula and converting bandwidth units to demonstrate how packet size relates to transmission duration. The segment concludes with the instructor circling the 2*Tp term to emphasize its significance as RTT in performance calculations.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor presents a slide titled 'Measuring Performance for Stop and Wait' displaying the full total time formula: Tt(data) + Tp(data) + Delayque + Delaypro + Tt(ack) + Tp(ack). The slide progressively simplifies this by stating 'Queuing delay and processing delays are generally kept 0' and noting that Tt(ack) is negligible because acknowledgment size is very small. The final simplified formula shown is 'Total Time = Tt(data) + 2*Tp', with a note that 'Some times 2 * Tp time is also called Round Trip Time (RTT)'. A hand-drawn diagram on the right shows vertical lines labeled S and R with diagonal arrows forming a triangle to visualize the sender-receiver exchange.

  2. 2:00 – 5:00 02:00-05:00

    The instructor stands before the slide showing the total time expression and begins introducing a numerical example. He writes '1Mb/s' on the board beside the sender label S in the diagram, establishing the link bandwidth for calculations. The slide continues to display the simplification steps from the full formula down to 'Total Time = Tt(data) + 2*Tp'. The instructor points to the initial formula and then to the simplified version, reinforcing the reduction process. He writes '700' on the board and begins setting up a calculation example with '1 Mbps -> Ls' and 'Lb = 1M' at the bottom, preparing to compute transmission time for a specific packet size.

  3. 5:00 – 10:00 05:00-10:00

    The instructor works through the numerical example, writing handwritten conversions at the bottom of the board: '1 Mbps -> 1s', '1b -> 1/1M', and the transmission time formula '= L/B'. A circled expression 'T = ?/5' appears, indicating the calculation of transmission time for a packet. The diagram on the right now shows the link marked '1 Mb/s' with additional written values including '700'. The instructor crosses out terms in the formula to highlight which components are eliminated under standard assumptions, explaining that Tt(ack) is negligible due to small acknowledgment size. The slide note 'Note:- Sometimes 2 * Tp time is also called Round Trip Time (RTT)' remains visible as the instructor connects the simplified formula to practical bandwidth calculations.

  4. 10:00 – 11:09 10:00-11:09

    The instructor concludes the segment by pointing to the formula for Total Time on the whiteboard and circling the 2*Tp term to emphasize its role as Round Trip Time. The slide displays 'Total Time = Tt(data) + 2*Tp' with the note about RTT clearly visible. The handwritten calculations at the bottom show '1 Mbps -> Ls' and '= L/B', reinforcing the transmission time computation method. The instructor uses visual annotations including circles around key terms to highlight important parts of the equation, ensuring students recognize that 2*Tp represents the round trip propagation delay in Stop and Wait performance analysis.

The lecture systematically derives the total time formula for Stop and Wait protocol performance measurement. Starting from a comprehensive expression with six delay components, the instructor applies three key simplifications: zero queuing/processing delays, negligible acknowledgment transmission time, and equal propagation times for data and acknowledgments. This yields the practical formula Total Time = Tt(data) + 2*Tp, where 2*Tp is defined as Round Trip Time. The hand-drawn S-R diagram with triangular arrow paths visually reinforces the sequential nature of Stop and Wait communication. The numerical example with a 1 Mbps link demonstrates how to compute transmission time using L/B, connecting the abstract formula to concrete bandwidth calculations. The progression from general formula to simplified expression to worked example follows a standard pedagogical pattern for networking performance analysis.

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