Practice Question (Throughput)

Duration: 6 min

This video lesson is available to enrolled students.

Return to /learn/UPPSC-POLYTECHNIC-LECTURER-2025-CS/paper-1-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: UPPSC Course Overview
  2. Interview Preparation & Guidance: Interview Preparation
  3. Paper 1 | General Hindi: 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, वर्णमाला, समास, संधि, 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), शब्द-भंडार, वर्ण-विचार, हिन्दी की ध्वनि और स्वनिम व्यवस्था, प्राचीन और मध्यकालीन भारतीय आर्यभाषाएँ, काव्य के लक्षण, हेतु और प्रयोजन, अशुद्धि-शोधन, शब्द-रचना, शब्द-भेद, हिन्दी की रूप रचना, रूप-रचना, हिन्दी शब्द रचना, हिन्दी साहित्येतिहास दर्शन, भक्तिकालीन काव्यधाराएँ, भारतीय काव्यशास्त्र की परंपरा, भारतीय नवजागरण और स्वाधीनता आंदोलन, अन्य गद्य विधाएँ एवं प्रवासी साहित्य, निर्धारित उपन्यासों का तुलनात्मक अध्ययन, गोदान, हिन्दी कहानी का विकास, स्वातंत्र्योत्तर और नयी कहानी, हिन्दी निबंध का विकास, शुक्लोत्तर निबंध, द्विवेदी और शुक्ल युग के निबंध, हिन्दी की संवैधानिक स्थिति, आधुनिक भारतीय आर्यभाषाएँ और हिन्दी का उद्भव, हिन्दी भाषा प्रयोग के विविध रूप, रीतिकाल, जीवनी, द्विवेदी युग और छायावाद, रीति, वक्रोक्ति और औचित्य सिद्धान्त, शब्दशक्ति और ध्वनि सिद्धान्त, रस सिद्धान्त और साधारणीकरण, उत्तर आधुनिकतावाद, लोहिया दर्शन, हिन्दी उपन्यास का विकास, हिन्दी नवजागरण, अंबेडकर दर्शन, आदिकाल, प्रयोगवाद और नयी कविता, छायावादी काव्य: प्रसाद और निराला, प्रगतिवाद से समकालीन कविता, निर्गुण भक्ति काव्य, द्विवेदीयुगीन काव्य, रीतिकालीन काव्य, आरंभिक हिन्दी उपन्यास, स्वातंत्र्योत्तर उपन्यास, आत्मकथा, स्वाधीनता-पूर्व प्रेमचंदोत्तर उपन्यास, निर्धारित कहानियों का तुलनात्मक अध्ययन, साठोत्तरी नाटक, प्रसाद और प्रसादोत्तर युग के नाटक, भारतेन्दु युगीन नाटक, स्वातंत्र्योत्तर नाटक, भारतेन्दु युगीन निबंध, संस्मरण और रेखाचित्र, व्यंग्य, एक साहित्यिक की डायरी, संस्कृति के चार अध्याय, सगुण भक्ति काव्य, हिन्दी नाटक, एकांकी और रंगमंच, आधुनिक गद्य और हिन्दी नवजागरण, अलंकार सिद्धान्त, हिन्दी आलोचना का विकास, भक्ति आंदोलन, कल्पना, बिम्ब, प्रतीक, मिथक और फंतासी, नयी कविता का विस्तार और साठोत्तरी कविता, उत्तर-छायावादी और प्रगतिवादी काव्य, काव्यगुण और काव्यदोष, प्लेटो, अरस्तू और पाश्चात्य परंपरा, मार्क्सवाद, स्वच्छन्दतावादी काव्यशास्त्र, आधुनिक पाश्चात्य आलोचना, भाषा और भाषा परिवार, देवनागरी लिपि
  4. Paper 2 | General Studies: State Wise GK, Polity, Geography, History, GK- Current Affairs
  5. Paper 1 | Programming Language: Language Design, C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, OOPS with C++
  6. Paper 1 | Database Management Systems: 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, ORDBMS, NoSQL
  7. Paper 1 | Cyber Security: Society, Law & Ethics, 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, Ethical Hacking
  8. Paper 1 | Computer Organization and Architecture: Basics of COA, Programming the Basic Computer, Cache Memory Organization, Input Output Organisation, Instr Formats & Modes, Register Transfer and Microoperations, Control Unit Design
  9. Paper 1 | 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, Network Security
  10. Paper 1 | Design and Analysis of Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  11. Paper 1 | Data Structures: Introduction to DS, Array, Linked List, Stack, Queue, Tree, Graphs, Hashing
  12. Paper 1 | Discrete Structures and Theory of Logic: Permutation and Combination, Set Theory, Relations, Functions, Propositional and Predicate Logic, Graph Theory, Group Theory
  13. Paper 1 | Software Project Management: Software Project Management
  14. Paper 2 | Operating Systems: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Unix OS, Linux OS, Security
  15. Paper 2 | 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, Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Pushdown Automata & CFG, Complexity Theory
  16. Paper 2 | Artificial Intelligence & High Performance Computing: Approaches to AI, Search Algorithms, Game Playing, Knowledge Representation, Planning, Multi Agent Systems, Natural Language Processing, Emerging Tech Trends
  17. Paper 2 | Image Processing: Digital Image Fundamentals, Image Enhancement, Image Restoration, Color Image Processing, Image Compression
  18. Paper 2 | Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  19. Paper 2 | Computer Graphics: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, 3-D Object Representation, Geometric Transformations and Viewing
  20. Paper 2 | Web Technologies: Website, Browser & Services, Internet Fundamentals, Web Design & Development, Protocols & Services, Web Publishing & Hosting, Server Side & Security, Emerging Technologies, HTML Basics, JavaScript-Basics, Java
  21. Paper 2 | Soft Computing: Fuzzy Sets, Artificial Neural Networks, Genetic Algorithms
  22. Paper 2 | Distributed System: Distributed Systems
  23. UPPSC Live Class Recordings: UPPSC Polytechnic Lecturer 2025 (CS)
  24. Previous Year Papers:
  25. Mock Test:
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…