CIDR Practice Question

Duration: 8 min

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Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
  2. Paper 2 | Digital Logic: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Floating Point Rep
  3. Paper 2 | Computer Organization And Architecture: Basics of COA, Cache Memory Organization, Input Output Organisation, Pipelining, Control Unit Design, Instr Formats & Modes, Programming the Basic Computer
  4. Paper 2 | Analog And Digital Communication: Introduction to Communication Systems & Random Signals, Analog Communication Systems, Information Theory & Digital Communication Fundamentals, Digital Modulation & Detection Techniques, Error Control, Synchronization & Multiple Access Techniques
  5. Paper 2 | Programming in C: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  6. Paper 2 | Data Structures And Programming: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Java, OOPS with C++, Java Fundamentals, Array, String, IO & References
  7. Paper 2 | Algorithms: Algorithm Analysis, Sorting Algorithms, Time Complexity Analysis, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos
  8. 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
  9. Paper 2 | Operating System: 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
  10. Paper 2 | Databases: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, Relational Algebra, SQL, Relational Calculus, File Organization & Indexing, Transaction Management, Concurrency Control
  11. Paper 2 | Information Systems and Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  12. Paper 2 | 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
  13. Paper 2 | Internet & Web Technologies: Website, Browser & Services, Internet Fundamentals, Web Design & Development, Protocols & Services, Web Publishing & Hosting, Server Side & Security, Emerging Technologies, HTML Basics, JavaScript-Basics, CSS, XML, HTML5
  14. Paper 2 | Cyber Security And Emerging Technologies: Emerging Tech Trends
  15. Paper 2 | Cloud Technology: Cloud Computing
  16. Paper 2 | Probability and statistics: Probability, Statistics
  17. Paper-1 English: Vocabulary, Preposition, Articles, Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Sentence Correction (Error Correction), Sentence Completion (Fill in the blanks), Cloze Test (Cloze Passage), Sentence Construction
  18. Paper 1 General Mental Ability & Logical reasoning: 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, Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Percentage, Average, Powers and Exponents (Surds and Indices), Algebra, Profit and Loss, Simple Interest and Compound Interest, Time and Work, Pipe and Cistern, Mensuration and Geometry, Mental Ability, Age Problems, Partnership, Arithmetic, Speed Mathematics and Basic Mathematics, Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Seating Arrangements, Blood Relations, Directions (Direction Test), Analytical Reasoning (Counting Figures Reasoning), Puzzle Solving (Puzzles), Calendar, Clock, Cubes & Dices, Selection Decision Table (Decision Making), Logical Sequence Of Words, Venn Diagram, Analogy
  19. Paper-1 General Knowledge & Current Affairs: State Wise GK, History, Geography, GK- Current Affairs, Static General Knowledge
  20. Full Length Mock Test:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video provides a step-by-step guide to Variable Length Subnet Masking (VLSM) using a specific networking problem. The instructor starts with a single Class C network, 200.1.2.0/24, and demonstrates how to divide it into three distinct subnets with varying host requirements: one subnet needing 126 hosts and two others needing 62 hosts each. The lecture emphasizes the importance of allocating the largest subnet first to prevent address fragmentation. Through a combination of whiteboard drawing and slide presentation, the instructor derives the correct subnet masks (/25 and /26) and calculates the precise IP address ranges for each resulting subnet, concluding with a summary of CIDR formulas.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video begins with the instructor presenting a specific problem statement on the screen: "Consider we have a big single network having IP Address 200.1.2.0/24. We want to do subnetting and divide this network into 3 subnets, such that first contains 126 hosts, and other two contains 62 hosts each?" He starts the solution by writing the network address 200.1.2.0/24 at the top of the screen. He then draws a large blue circle to represent the entire available IP address space. To the left of the circle, he writes the number "3" in a red circle, indicating the three subnets required. He proceeds to draw a vertical red line down the center of the blue circle, effectively splitting the address space into two equal halves, which is the first step in allocating the largest subnet.

  2. 2:00 – 5:00 02:00-05:00

    The instructor focuses on the first requirement: a subnet with 126 hosts. He explains that to support 126 usable hosts, the subnet must have a block size of 128 (2^7), because 2^7 - 2 = 126. This means 7 bits are needed for hosts, leaving 25 bits for the network prefix (32 - 7 = 25). He writes /25 next to the left half of the circle. Next, he addresses the remaining right half of the circle, which needs to be split into two subnets of 62 hosts each. For 62 hosts, he calculates a block size of 64 (2^6), requiring 6 host bits and a prefix length of 26 (32 - 6 = 26). He draws a horizontal line to split the right side into two quadrants and writes "62" in each. He then writes the specific subnet IDs on the right: 200.1.2.128/26 and 200.1.2.192/26, explaining the binary values 10000000 (128) and 11000000 (192) that determine these starting addresses.

  3. 5:00 – 7:43 05:00-07:43

    The instructor transitions to a slide that summarizes the final calculated subnets. The slide is divided into three sections: "1st Subnet", "2nd Subnet", and "3rd Subnet". For the 1st Subnet, it lists the IP Address as 200.1.2.0, Direct Broadcast Address as 200.1.2.127, and the Range of IP Addresses as [200.1.2.0, 200.1.2.127]. The 2nd Subnet is listed as 200.1.2.128/26 with a range of [200.1.2.128, 200.1.2.191]. The 3rd Subnet is 200.1.2.192/26 with a range of [200.1.2.192, 200.1.2.255]. Finally, a slide titled "Designing subnets for CIDR Notations" appears, showing the formula n_sub = 32 - log_2 N_sub and stating the rule that the starting address must be divisible by the number of addresses in the sub-network.

The lecture successfully bridges the gap between theoretical subnetting rules and practical application. By visually splitting the address space circle, the instructor makes the abstract concept of binary division concrete. The progression from identifying the largest host requirement to calculating the corresponding prefix length and finally listing the specific IP ranges provides a clear, repeatable method for solving VLSM problems. The inclusion of the CIDR formula slide at the end reinforces the mathematical foundation behind the visual steps, ensuring students understand both the "how" and the "why" of the subnetting process.

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