CIDR block representation practice question

Duration: 4 min

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Inside: a video lesson and guided study material.

Module outline

  1. Quantitative Aptitude: Number System, Divisibility Rules, HCF LCM, Percentage, Ratio and Proportion (Ratios), Average, Profit and Loss, Simple Interest and Compound Interest, Mixture and Alligation, Partnership, Age Problems, Time and Work, Pipe and Cistern, Speed Time and Distance, Algebra, Arithmetic, Data Interpretation, Sequence and Series (Series), Logarithm, Powers and Exponents (Surds and Indices), Permutation and Combination, Probability, Speed Mathematics and Basic Mathematics, Trigonometry
  2. Logical Reasoning: Coding Decoding, Blood Relations, Directions (Direction Test), Ranking, Order and Sequence, Seating Arrangements, Puzzle Solving (Puzzles), Data Arrangement, Syllogisms, Inequality, Data Sufficiency, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Series (Number and Letter Series) (Numerical Relations and Reasoning), Venn Diagram, Logical Sequence Of Words, Calendar, Clock, Cubes & Dices, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning)
  3. Verbal Ability: Noun, Pronoun, Adjectives, Verb, Adverb, Tenses, Subject Verb Agreement (Verb Noun Agreement), Articles, Preposition, Conjunction, Modals, Determiner, Vocabulary, Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Cloze Test (Cloze Passage), Sentence Correction (Error Correction), Sentence Completion (Fill in the blanks), Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Active Passive Voice (Voice), Direct and Indirect Speech, Sentence Construction
  4. Data Structures (Domain Test): Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
  5. Algorithms (Domain Test):
  6. OOPs (Domain Test): Object Oriented Programming (OOPS)
  7. DBMS (Domain Test): Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, ORDBMS, Database Security & Authorization, Query Processing & Optimization, Enhanced Data Models, Data Warehousing & Mining, Big Data Systems, NoSQL
  8. SQL (Domain Test): SQL
  9. Operating Systems (Domain Test): Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling, File Management, Windows OS, Linux OS, Security, Distributed Systems, Virtual Machines
  10. Computer Networks (Domain Test): 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, Cloud Computing and IoT, Cyber and Info Security
  11. Coding: Coding Questions by Yash Sir, C Programming by Yash Sir, Programming in C++, Java, Python for Placements by Yash Sir
  12. Written English Test: English Writing Ability
  13. Psychometric Test: Behavioral Assessment (Behavioral Competency Profiling) (Psychometric Test)
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The video lecture focuses on determining if a specific range of IP addresses constitutes a valid Classless Inter-Domain Routing (CIDR) block and finding its representation. The instructor presents a problem involving the range 100.1.2.32 to 100.1.2.47. He systematically applies three rules: contiguity, power-of-2 size, and divisibility of the first address. Through step-by-step calculation, he verifies the block size is 16, confirms it is a power of 2, and checks if the starting address is divisible by 16. Finally, he derives the CIDR notation /28. The lecture is structured around a specific question displayed on the slide, guiding the student through the verification process.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor introduces the problem statement displayed on screen: "Consider a block of IP Addresses ranging from 100.1.2.32 to 100.1.2.47." He underlines the question "Is it a CIDR block?" and lists the "Rules for Creating CIDR Block (Network)". He begins calculating the total number of addresses by subtracting the start from the end: "47 - 32". He emphasizes the need to add 1 for inclusive counting, writing "(47 - 32) + 1". He explains the "plus 1" concept using a small example "0-9" resulting in 10 numbers. He calculates the total size as 16. He writes "15 + 1" and circles "16". He also writes "35" and "35" vertically, seemingly checking something else or just scribbling, but focuses on the 16.

  2. 2:00 – 3:38 02:00-03:38

    The instructor verifies the calculated size of 16 against the rules. He checks if 16 is a power of 2, noting the sequence "8, 16, 32, 64, 128" written on the board. He then applies the third rule: "First IP Address of the block must be divisible by the size of the block." He writes "32 / 16" and confirms the result is 2, meaning it divides evenly. He concludes it is a valid CIDR block. He then determines the CIDR representation. Since the block size is 16 ($2^4$), he deduces the host bits are 4. He calculates the network prefix as $32 - 4 = 28$. He writes the final answer "100.1.2.32 / 28". He also draws a diagram of 32 bits to visualize the host bits.

The lesson effectively demonstrates the algorithmic approach to validating CIDR blocks. By breaking down the problem into size calculation, power-of-2 verification, and divisibility checks, the instructor provides a clear method for students to solve similar networking problems. The final derivation of the /28 prefix solidifies the connection between block size and CIDR notation. The visual aids, such as the list of powers of 2 and the divisibility check, reinforce the theoretical rules with practical application.

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