TCP Header-Urgent Pointer Field

Duration: 4 min

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Module outline

  1. Paper 1 | Reasoning Test: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Seating Arrangements, Blood Relations, Puzzle Solving (Puzzles), Venn Diagram, Analogy, Ranking, Order and Sequence, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Selection Decision Table (Decision Making), Logical Sequence Of Words, Cubes & Dices, Analytical Reasoning (Counting Figures Reasoning), Calendar, Alphabet and Word Tests, Numerical Reasoning, Number System, Averages, Mixtures and Alligation, Percentages, Series Completion, Analogy and Classification, Patterns in Two-Dimensional Figures, Coding and Decoding, Mathematical Operations, Direction Sense, Algebra, Logical Deduction and Induction, Syllogisms and Venn Diagrams, Critical Reasoning, Order, Ranking and Sequence, Reading Comprehension, Profit, Loss and Discount, Constraint Puzzles, Speed, Time and Distance, Traverse Surveying, Ratio and Proportion, Time and Work, Mensuration, Permutations and Combinations, Clocks and Calendars, Data Interpretation, Assembling and Grouping of Shapes, Transformation of Shapes, Three-Dimensional Patterns and Visualization, Cubes and Dice, Vocabulary, Blood Relations, Data Sufficiency
  2. Paper 1 | Numerical Analysis: Number System, HCF LCM, Percentage, Ratio and Proportion (Ratios), Average, Sequence and Series (Series), Powers and Exponents (Surds and Indices), Algebra, Statistics, Data Interpretation, Mental Ability, Arithmetic, Logarithm, Profit and Loss, Simple Interest and Compound Interest, Speed Time and Distance, Mixture and Alligation, Mensuration and Geometry, Permutation and Combination, Probability, Sequences and Series, Powers, Surds and Logarithms, Subject-Verb Agreement, Sentence Completion, Geometry, Sentence Structure and Correction, Data Sufficiency, Trigonometry, Measurement and Quantity Take-Off, Signal Space and Optimum Detection, Probability, Statistics, Algebra, Time and Work, Speed, Time and Distance, Data Interpretation, Graph Theory, Combinatorics
  3. Paper 1 | General Knowledge: State Wise GK, History, Geography, GK- Current Affairs, Static General Knowledge, Polity, Indian Economy
  4. Paper 1 | 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, Transaction Management, Concurrency Control, Relational Calculus, Database Security & Authorization, Database Recovery
  5. Paper 1 | Data Communication & Network: 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, Network Security, Security in Mobile and Wireless Computing, Input Output Organisation, File Management, Hardware Basics, Terms & Abbreviations, Protocols & Services, Network Access Technologies, Cyber Safety and Security, Basics of COA
  6. Paper 2 | System Analysis & Design: Fundamentals of Systems and Information Systems, SDLC and Development Approaches, Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Documentation and Software Requirements Specification (SRS), SDD and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, Security, Risk Management & Maintenance, extras
  7. Paper 2 | Programming Language (Java): Java Fundamentals, OOPS with Java, Array, String, IO & References, Generic & Collections, Multithreading, Java, Miscellaneous, Control Flow, OOPS with C++, Stack, C Fundamentals, Arrays & Pointers, Object Oriented Technology, Control Flow & Looping, Introduction to Python
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This short lecture segment focuses exclusively on the Urgent Pointer field within a TCP header. The instructor presents a slide defining the 16-bit urgent pointer as valid only when the urgent flag is set, used to indicate the position of urgent data. A hand-drawn diagram illustrates how the sequence number and urgent pointer combine to locate the last urgent byte in the data section. The instructor repeatedly points to the urgent pointer field in a TCP header layout, emphasizing that it is an offset added to the sequence number rather than an absolute address. The on-screen text consistently states: 'This 16-bit field, which is valid only if the urgent flag is set, is used when the segment contains urgent data. It defines the number that must be added to the sequence number to obtain the number of the last urgent byte in the…' The header diagram labels fields including source port address, destination port address, sequence number (32 bits), acknowledgment number, window size, and urgent pointer (16 bits). No worked numerical example is shown; the teaching relies on visual annotation and field identification.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor introduces the Urgent Pointer field, displaying on-screen text: 'This 16-bit field, which is valid only if the urgent flag is set, is used when the segment contains urgent data.' A hand-drawn diagram with an 'S' and arrow pointing to the data section illustrates how sequence number plus urgent pointer locates the last urgent byte. The TCP header structure at the bottom highlights the Urgent Pointer field alongside source port address, destination port address, sequence number, acknowledgment number, and window size. The instructor uses a pen to annotate the diagram and point at specific fields.

  2. 2:00 – 3:32 02:00-03:32

    The instructor continues pointing to the 'Urgent pointer' field in the TCP header diagram, emphasizing its 16-bit size and relationship to the 32-bit sequence number. On-screen text reiterates: 'It defines the number that must be added to the sequence number to obtain the number of the last urgent byte in the…' The instructor gestures toward the data section and points to the 'Urgent' flag in the header flags row, clarifying that the urgent pointer is a relative offset rather than an absolute address. The slide displays 'Urgent pointer 16 bits' and 'Sequence number 32 bits' as labeled field breakdowns.

The core concept is that the TCP Urgent Pointer is a 16-bit offset field, not an absolute byte address. It is only meaningful when the URG flag in the TCP header is set to 1. The field value is added to the segment's sequence number to compute the sequence number of the last urgent byte in the data payload. The instructor reinforces this through repeated pointing to the field in a header layout diagram and a hand-drawn schematic showing sequence number plus urgent pointer pointing into the data section. Key distinctions: (1) validity is conditional on the urgent flag; (2) it is an offset, not a direct position; (3) it identifies the last urgent byte, not the first. No numerical worked example is provided in the sampled frames; the lesson relies on structural identification and conceptual clarification. Students should remember: Urgent Pointer + Sequence Number = sequence number of last urgent byte, and the field is ignored if URG=0.

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