Rules of Creating CIDR Block

Duration: 4 min

This video lesson is available to enrolled students.

Return to /learn/GATE-GUIDANCE-BY-SANCHIT-SIR/computer-networks/net-layer-ip-addressing/cidr-vlsm/asset-rules-of-creating-cidr-block after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. Discrete Mathematics: Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic
  2. DataBase Management System/DBMS: 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
  3. Digital Electronics: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation
  4. Computer Architecture: Floating Point Rep, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Control Unit Design
  5. Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management
  6. C Language: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  7. Data Structures: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
  8. Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos
  9. 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
  10. Theory Of Computation/Automata Theory: 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
  11. 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
  12. Engineering Mathematics: Permutation and Combination, Linear Algebra, Calculus, Probability, Statistics
  13. General Aptitude: Ratio and Proportion (Ratios), Divisibility Rules, Data Interpretation, 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, Mensuration and Geometry, Mental Ability, Arithmetic, Profit and Loss, Powers and Exponents (Surds and Indices), Average, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Syllogisms, Venn Diagram, Seating Arrangements, Blood Relations, Directions (Direction Test), Analogy, Algebra, Time and Work, Analytical Reasoning (Counting Figures Reasoning), Puzzle Solving (Puzzles), Cubes & Dices, Ranking, Order and Sequence, Mixture and Alligation, Age Problems, Clock, Selection Decision Table (Decision Making), Data Arrangement
  14. English (Verbal Aptitude): Vocabulary, Noun, Subject Verb Agreement (Verb Noun Agreement), Adjectives, Tenses, Pronoun, Preposition, Direct and Indirect Speech, Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Sentence Completion (Fill in the blanks), Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Sentence Correction (Error Correction), Verbal Analogy (Word Based Analogy), Conjunction, Interjection, Verb, Articles, Adverb, Modals, Sentence Construction
  15. Live Classes Recordings(Earlier Batch): GATE 2026 Live Class
  16. Full Mock Test:
  17. Previous Year Papers:
  18. GATE 2026 Counselling: Counselling and Guidance Sessions
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This lecture segment introduces the three fundamental rules for creating a valid CIDR block (network). The instructor presents a slide titled “Rules for Creating CIDR Block (Network)” listing: (1) all IP addresses in the block must be contiguous; (2) the block size, i.e., total number of IP addresses contained in the block, must be representable as a power of 2 (e.g., 2^1, 2^2, 2^3, 2^4, 2^5); and (3) the first IP address of the block must be divisible by the size of the block. The instructor then works through an example using the IP address 167.92.48.32, writing it on the board and performing related calculations involving values such as 256 and binary representations (e.g., “10000” and “11111”) to illustrate the divisibility rule. A division calculation (2300 / 106) is also shown on the right side of the board, though its exact role in the example is not fully clear from the sampled screenshots. The segment emphasizes how to verify whether a given IP address can serve as the base of a CIDR block by checking contiguity, power-of-2 size, and divisibility.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The slide “Rules for Creating CIDR Block (Network)” lists three bullets: IP addresses must be contiguous, block size must be a power of 2 (shown as “2^1, 2^2, 2^3, 2^4, 2^5”), and the first IP address must be divisible by the block size. The instructor writes “167 92 48 32” on the right, adds small figures “6” and “3” beneath the last octet, and begins a bracketed column with “17” over “17,” indicating the start of a worked example next to the rules.

  2. 2:00 – 4:26 02:00-04:26

    The instructor continues the example with 167.92.48.32, writing “256” and “257” on the board and drawing a binary representation with 16 host bits circled. A division calculation (2300 / 106) appears on the right side, and the instructor points to binary digits “10000” and “11111.” The final frame shows the three rules again with “256” and “167.92.48” on the right, reinforcing that block size must be a power of 2 and the base address must be divisible by it.

The core teaching point is that a valid CIDR block must satisfy three conditions: contiguity of addresses, power-of-2 size, and divisibility of the base address by the block size. The instructor uses 167.92.48.32 as a concrete example, writing it on the board and performing calculations involving 256 (a power of 2) and binary representations to demonstrate how the divisibility rule works. The presence of “10000” and “11111” suggests the instructor is showing how host bits or block boundaries align in binary. The division (2300 / 106) is visible but its exact purpose in the example is not fully clear from the sampled screenshots; it may relate to a different aspect of CIDR calculation or be part of an intermediate step. The segment is focused on rule application rather than deriving the rules from first principles.

Loading lesson…