ClassLess Interdomain Routing - CIDR With Example

Duration: 4 min

This video lesson is available to enrolled students.

Return to /learn/RSSB-BASIC-COMPUTER-INSTRUCTOR/paper-2-data-communication-and-network-security/net-layer-ip-addressing/cidr-vlsm/asset-classless-interdomain-routing-cidr-with-example after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. About the Course: About the Course
  2. Paper-1 & 2 | Basic Numeracy: Ratio and Proportion (Ratios), Divisibility Rules, Mixture and Alligation, Permutation and Combination, Logarithm, Number System, HCF LCM, Sequence and Series (Series), Speed Time and Distance, Percentage, Average, Mensuration and Geometry, Age Problems, Arithmetic, Statistics, Probability, Profit and Loss, Simple Interest and Compound Interest, Partnership, Speed Mathematics and Basic Mathematics, Algebra, Powers and Exponents (Surds and Indices), Time and Work, Pipe and Cistern, RSSB Specific Videos - Basic Numeracy
  3. Paper-1 & 2 | Data Interpretation: Data Interpretation
  4. Paper-1 & 2 | General Mental Ability: Mental Ability, RSSB Specific Videos - Mental Ability
  5. Paper-1 & 2 | Logical Reasoning and Analytical Ability: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Syllogisms, Seating Arrangements, Blood Relations, Directions (Direction Test), Analytical Reasoning (Counting Figures Reasoning), Puzzle Solving (Puzzles), Calendar, Clock, Cubes & Dices, Venn Diagram, Analogy, Ranking, Order and Sequence, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Data Arrangement, Logical Sequence Of Words, Crypt Arithmetic
  6. Paper-1 & 2 | Decision Making and Problem Solving: Selection Decision Table (Decision Making)
  7. Paper-1 | General Science: Physics, Biology, Chemistry, RSSB Specific Videos
  8. Paper-1 | General Awareness: State Wise GK, GK- Current Affairs
  9. Paper - 2 | Digital Logic Systems: Digital Systems & Boolean Basics, Logic Gates & Hardware, Combinational Circuit, Sequential Circuits
  10. Paper-2 | Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, Relational Calculus, Relational Algebra, SQL, NoSQL
  11. Paper-2 | Data Structures & Algorithms: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Algorithm Analysis, Sorting Algorithms, Intro to Compilers, Hashing
  12. Paper 2 | Data Communication and Network Security: Introduction to CN, Data Communication, Data Link Layer - Ethernet, DLL: Error Control, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Application Layer, Hardware basics, Network Security, Ethical Hacking
  13. Paper-2 | Operating Systems: Introduction to OS, Process Management, Memory Management, File Management, Deadlock
  14. Paper-2 | Computer Organization and Architecture: Basics of COA, Floating Point Rep, Cache Memory Organization, Input Output Organisation, Instr Formats & Modes, Control Unit Design, Register Transfer and Microoperations, Programming the Basic Computer, Number System, Number Representation
  15. Paper 2 | System Analysis and Design: Fundamentals of Systems and Information Systems, Fundamentals of Software Engineering, SDLC and Development Approaches, Software Documentation and Software Requirements Specification (SRS), SDD and Quality Assurance, Security, Risk Management & Maintenance, Software Testing
  16. Paper-2 | C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  17. Paper 2 | OOPS , C++ , JAVA: Language Design, OOPS with C++, Java, .Net Programming, Java Fundamentals
  18. Paper 2 | Python: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis
  19. Emerging Trends and AI: Emerging Tech Trends, Artificial Intelligence
  20. Paper-2 | Data Processing (Ms-Office): MS Office Applications
  21. Paper-2 | Internet and Web Technologies: HTML Basics, CSS, XML, JavaScript-Basics, Internet Fundamentals, Protocols & Services, Web Publishing & Hosting, Server Side & Security, Emerging Technologies, Terms & Abbreviations, Cyber Threats and Malware Attacks, Role of Internet and Web Services, Security in Mobile and Wireless Computing, साइबर सुरक्षा / Cyber Safety and Security, कंप्यूटर नेटवर्क / Computer Networks
  22. Paper 2 | Pedagogy: Child Development, Theories, Concept of Pedagogy, Inclusive Education, Experiential Pedagogy, Assessment & Evaluation, Psychology, Curriculum Framework & Reforms, National Education Policy (NEP) 2020
  23. Live Classes: RSSB Live Sessions
  24. Paper 1 - Full Mock Tests:
  25. Paper 2 - Full Mock Tests:
  26. BCI Previous Year Papers:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This lecture segment teaches how to determine the number of addresses, first address, and last address for a CIDR block using an address mask. The instructor works through the example 167.199.170.82/27, showing its binary form 10100111 11000111 10101010 01010010. The mask is formed by setting the 27 leftmost bits to 1 and the remaining 5 bits to 0. The number of addresses is calculated as N = NOT(mask) + 1, which equals 2^5 = 32. The first address is found by ANDing the given address with the mask, yielding 167.199.170.64. The last address is found by ORing the given address with NOT(mask), yielding 167.199.170.95. A summary slide titled “Address Mask” defines the mask as a 32-bit number with n leftmost bits set to 1 and the rest 0, and lists the three bitwise operations NOT, AND, and OR used to compute block properties.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The slide presents the question “Find the Number of addresses, first and last address of the CIDR block to which” with “Address: 167.199.170.82/27 (10100111 11000111 10101010 01010010) belongs to.” The instructor circles the address line and underlines binary octets, isolating the final group “01010010.” He then writes “2^5 = 32” on the whiteboard, indicating that with a /27 prefix there are 5 host bits and therefore 32 addresses in the block.

  2. 2:00 – 4:15 02:00-04:15

    A second slide states “The mask by setting 27 leftmost bits to 1 and 5 rightmost bits to 0 in dotted-decimal notation is:” and “Number of addresses in the block: N = NOT (mask) + 1 =”, with “NOT” circled in red. The instructor sketches tally marks and five circles representing the zero bits. Later slides show “First address: First = (address) AND (mask) =” and “Last address: Last = (address) OR (NOT mask) =”, with binary rows for the AND and OR operations. The computed first address 167.199.170.64 and last address 167.199.170.95 appear on screen. A final “Address Mask” slide defines the mask as a 32-bit number with n leftmost bits set to 1 and lists N = NOT(mask) + 1, first address = (any address in block) AND mask, and last address = (any address in block) OR NOT(mask).

The lesson centers on CIDR address-mask arithmetic. The key rule is that a /n prefix creates a mask with n leading 1-bits and (32-n) trailing 0-bits. From this mask, three bitwise formulas give block properties: N = NOT(mask) + 1 for the number of addresses, first address = address AND mask, and last address = address OR NOT(mask). In the worked example 167.199.170.82/27, the five trailing zero bits give 2^5 = 32 addresses. ANDing with the mask clears host bits to produce the first address 167.199.170.64, while ORing with NOT(mask) sets host bits to 1 to produce the last address 167.199.170.95. The progression moves from identifying the prefix length, to constructing the mask, to applying NOT/AND/OR operations, and finally to a summary slide that generalizes the method.

Loading lesson…