Practice Question (Throughput)

Duration: 6 min

This video lesson is available to enrolled students.

Return to /learn/UP-LT-GRADE-ASSISTANT-TEACHER-2025/cs-08-computer-networks/dll-access-control/aloha-protocols/asset-practice-question-throughput after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
  2. CS | 01 | Digital Logic and Circuits and Discrete Mathematical Structures: Digital Systems & Boolean Basics, Number System, Number Representation, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic, Permutation and Combination
  3. CS | 02 | Computer Organization and Architecture: Basics of COA, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Control Unit Design, Multiprocessors
  4. CS | 03 | Data Structures and Algorithm: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Complexity Theory, Advanced Algorithms
  5. CS | 04 | Problem Solving through C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  6. CS | 05 | Object Oriented Techniques: Object Oriented Technology, Java
  7. CS | 06 | Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Windows OS, Unix OS
  8. CS | 07 | Database Management Systems: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, Relational Algebra, SQL, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, Database Security & Authorization, Query Processing & Optimization, File Organization & Indexing
  9. CS | 08 | Computer Networks: 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, Hardware basics
  10. CS | 09 | Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  11. CS | 10 | Internet Technology, Web Design and Web Technology: Internet Fundamentals, Web Design & Development, Protocols & Services, Web Publishing & Hosting, Server Side & Security, Emerging Technologies, JavaScript-Basics, HTML Basics
  12. CS | 11 | System Analysis And Design: Fundamentals of Systems and Information Systems, SDLC and Development Approaches, Software Documentation and Software Requirements Specification (SRS), SDD and Quality Assurance, Security, Risk Management & Maintenance
  13. CS | 12 | Information Security and Cyber Laws: Cyber Threats and Malware Attacks, Role of Internet and Web Services, Security in Mobile and Wireless Computing, Electronic Data Interchange and E-Commerce, Physical Security and Cryptography Basics, Intrusion Detection Systems (IDS), Cyber Safety and Security
  14. CS | 13 | Computer Graphics: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, 3-D Object Representation, Geometric Transformations and Viewing
  15. GS Paper | 01 | Indian and World Geography: Geography
  16. GS Paper | 02 | History: History
  17. GS Paper | 03 | Indian Economy & Social Development: Indian Economy
  18. GS Paper | 04 | General Science: Biology, Chemistry, वैज्ञानिक उपलब्धियाँ और अनुसंधान / Scientific Achievements and Research
  19. GS Paper | 05 | Elementary Maths: संख्या पद्धति / Number System, Divisibility Rules, महत्तम समापवर्तक और लघुत्तम समापवर्त्य / HCF and LCM, प्रतिशत / Percentage, लाभ, हानि और बट्टा / Profit, Loss and Discount, साधारण और चक्रवृद्धि ब्याज / Simple and Compound Interest, अनुपात और समानुपात / Ratio and Proportion, औसत / Average, समय और कार्य / Time and Work, समय, चाल और दूरी / Time, Speed and Distance, Algebra, घन क्षेत्रमिति / Solid Mensuration, आँकड़ा निर्वचन / Data Interpretation, Arithmetic, Statistics, Probability, Sequence and Series (Series), मिश्रण और एलिगेशन / Mixture and Alligation, Calculus, Trigonometry, Vectors, संख्या पद्धति और संख्या सिद्धांत / Number Systems and Number Theory, यूक्लिडीय ज्यामिति और क्षेत्रमिति / Euclidean Geometry and Mensuration, सांख्यिकी और प्रायिकता / Statistics and Probability, निर्देशांक ज्यामिति, सदिश और त्रिविमीय ज्यामिति / Coordinate Geometry, Vectors and 3D Geometry, बहुपद, समीकरण और सम्मिश्र संख्याएँ / Polynomials, Equations and Complex Numbers, समतल क्षेत्रमिति / Plane Mensuration, सरलीकरण, घातांक और करणी / Simplification, Indices and Surds, समुच्चय, संबंध, फलन और विविक्त गणित / Sets, Relations, Functions and Discrete Mathematics
  20. GS Paper | 06 | Indian Polity and Governance: Polity
  21. GS Paper | 07 | Current Events: समसामयिकी / Current Affairs
  22. UPLT Live Classes Notes: UPLT Live Classes
  23. UPLT Full Mock Tests Tier 1:
  24. UPLT Full Mock Tests Tier 2:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This lecture reviews pure ALOHA throughput calculations, beginning with a GATE-2021 practice question (Q.22) and then working through textbook Examples 12.2 and 12.3 to establish the method before returning to solve Q.22. The instructor emphasizes identifying frame size, channel rate, and offered load G, computing transmission time Tf = L/B, then applying S = G e^{-2G}. For Example 12.3, a 200-bit frame on a 200 kbps channel gives Tf = 1 ms; at 1000 frames/s, G = 1 and S ≈ 0.135 (13.5%). The maximum pure ALOHA throughput is Smax = 1/(2e) ≈ 0.184 (18.4%) at G = 1/2. Finally, for Q.22 with a 1000-bit frame on a 1 Mbps channel and 1000 frames/s, Tf = 1 ms, G = 1, so S ≈ 13.5%.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video opens on slide Q.22, a GATE-2021 pure ALOHA throughput problem: 1,000-bit frames on a 1 Mbps (≈10^6 bps) channel with transmissions following a Poisson process at 1,000 frames/s. The instructor then shifts to Example 12.2, circling the given values '200-bit frames' and '200 kbps', underlining 'average number of frames generated by the system', and writing G= in the corner. The core formula S = G x e^-2G is underlined, and the maximum throughput result Smax = 1/(2e) = 0.184 when G = 1/2 is highlighted as the key pure ALOHA result.

  2. 2:00 – 5:00 02:00-05:00

    The instructor works the throughput calculation using S = G * e^(-2G), circling the formula and the 18.4 percent maximum value. Handwritten annotations on the right introduce G1, G2 and a total G to break down frame generation rates (e.g., G1 = 2, then G1 = 1 and G2 = 1/2), with a note '1000 -> 184' linking frame rate to throughput. The lesson moves to Example 12.3: a pure ALOHA network transmitting 200-bit frames on a shared channel of 200 kbps. The frame transmission time is computed as 200/200 kbps = 1 ms and circled. For a system creating 1000 frames per second (1 frame per millisecond), G = 1, so S = G * e^-2G = 0.135 (13.5 percent) for case a, while the maximum throughput 0.184 (18.4 percent) is circled for case b.

  3. 5:00 – 6:15 05:00-06:15

    The video returns to the GATE-2021 problem Q.22, with red underlines highlighting '1,000 bits', '1 Mbps (≈ 10^6 bits per second)', and '1,000 frames per second'. Red handwritten work below the text shows Tf = L/B = 1000 x 1000 ns / 10^6, with the result '1ms' circled and an added '= 1'. The instructor then writes the throughput formula S = G x e^-2G, substitutes to get 1 x e^-2, and concludes with '= 13.5%', applying the same method demonstrated in Example 12.3 to solve the practice question.

The lecture teaches a consistent three-step method for pure ALOHA throughput problems. First, extract the frame length L and channel rate B to find transmission time Tf = L/B (in seconds). Second, determine the offered load G from the frame generation rate: if frames are created at a rate such that one frame is generated every Tf, then G = 1; more generally G equals the average number of frames generated per frame transmission time. Third, apply S = G e^{-2G} to find throughput as a fraction of channel capacity. The instructor repeatedly circles the formula and the maximum value Smax = 1/(2e) ≈ 0.184 (18.4%) at G = 1/2, contrasting it with the operating point G = 1 giving S ≈ 0.135 (13.5%). This pattern is first illustrated with Example 12.2 and the worked Example 12.3 (200-bit frames, 200 kbps channel, Tf = 1 ms), then transferred to the GATE-2021 Q.22 (1,000-bit frames, 1 Mbps channel, Tf = 1 ms), where the same G = 1 yields S ≈ 13.5%. The central takeaway is that pure ALOHA throughput depends only on the dimensionless offered load G, and that the maximum achievable efficiency is about 18.4%.

Loading lesson…