Course Overview

Curriculum status — 2026-27 revision CSE14B Computer Networks · Core — Year 1, Quarter 4. Renamed from CSE1405. Content unchanged.

The official description below is the old one; course codes in its body are pre-2026 codes.

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Course Overview

Computer networks form the basis of all digital communication. They are typically structured in layers. Each layer has clearly defined functions and algorithms, which we will discuss in class. Furthermore, the course also discusses potential security issues and defences in computer networks, thereby also providing an introduction to cryptographic notions utilized by those defence mechanisms.

In this 9-week course, you will learn how the internet works - the thing you are using to read this text. After these 9 weeks, you should be able to describe what your computer and other devices do such that you can read text on your screen.

Learning Objectives

1. Layered Architectures: Describe the principles of layered architectures, particularly the functions and purposes of all layers for the OSI reference model
2. Core Algorithms: Describe the core algorithms of each layer and provide arguments why these algorithms fulfill the function of the respective layer
3. Application: Apply the core algorithms to toy examples
4. Design: Design variants of core algorithms for a given scenario
5. Security: Identify security issues of each layer and choose suitable solutions

Assessment

• Grade: Based on written exam only
• Exam Format: Written, on-paper, closed-book
• Allowed Materials: Calculator
• Question Types: Multiple choice and open questions (no programming)
• Resit: Single resit opportunity available

Course Structure

Contact Hours

• Lectures: 8 weeks × 2 lectures × 2 hours
• Shared Labs: 8 weeks × 4 hours

Course Components

1. Lectures: New concepts illustrated through examples from the textbook
2. Reading Assignments: Two self-study assignments (Error Detection/Correction and Cryptography)
3. Tutorials: Seven tutorials to practice and apply concepts
4. Programming Assignments: Weekly assignments on Weblab
5. Practice Exam: Preparation for final assessment
6. Skill Circuit: Available at https://skills.ewi.tudelft.nl/edition/946

Course Schedule

Task Dependencies and Deadlines

Course Materials

Textbook

"Computer Networks" by Tanenbaum, Feamster, and Wetherall, Edition 6

Lecture Topics

• Introduction
• Data link layer
• MAC Sub-Layer
• Network Layer
• Transport Layer
• Application Layer
• Security

Self-Study Assignments

1. Error Detection and Correction

• Prerequisites: Lecture 1 background helpful but not required
• Time Estimate: ~4 hours (6500 words + 75 min videos)
• Purpose: Foundation for tutorials 1 and 2
• Deadline: Before Lecture 6

2. Cryptography

• Prerequisites: None, can be completed anytime
• Time Estimate: 3-4 hours (8200 words OR 120 min videos)
• Purpose: Understanding network security concepts
• Deadline: Before Lecture 10

Tutorials

Seven tutorials covering:

1. Error detection (based on Error Detection notes)
2. Error correction (based on Error Detection notes)
3. Sliding Window Protocols (based on Lectures 2-3)
4. Network layer (based on Lectures 6-8)
5. Transport layer I (based on Lectures 9-10)
6. Transport layer II + Application layer (based on Lectures 11-12)
7. Cryptography (based on Security & Cryptography notes)

Additional Resources

• Chapter summaries for each topic with key concepts and algorithms
• Practice exam questions
• Paper: "Do you need a blockchain?" for blockchain content
• Student-written proof on Internet Checksum algorithm validity

Important Notes

• The course is blended: complete self-study assignments, tutorials, and programming assignments in your own time
• Tasks have prerequisites - consult the dependency table to stay on track
• While tutorials and programming assignments are not graded, completing them on time is essential for following lectures
• Labs provide hands-on experience with Internet software (e.g., Wireshark)

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TU Delft's CSE14B Computer Networks is a core course in the BSc Computer Science and Engineering program that introduces the principles of modern computer networking. The course spans all layers of the OSI model – from physical and data link protocols up through network, transport, and application layers – including an introduction to network security. It is structured as a 9-week module with interactive components (lectures, labs, tutorials, and self-study) culminating in a comprehensive written exam. Below is a detailed overview of the course’s official learning objectives, weekly schedule, assignments, and assessment format, along with an analysis of recent exam content and how the curriculum aligns with the prescribed textbook and materials.

Official Learning Objectives

Upon completing CSE14B Computer Networks, students should be able to do the following (official learning outcomes):

1. Layered Architectures – Describe the principles of layered network architectures, particularly the functions and purposes of all layers in the OSI reference model.
2. Core Algorithms – Describe the core algorithms/protocols of each network layer and explain why those algorithms fulfill the function of their respective layer.
3. Application – Apply the core networking algorithms to toy examples and exercises (demonstrating practical understanding of how they work).
4. Design – Design and propose variants of core network algorithms for a given scenario (adapting standard protocols to new conditions).
5. Security – Identify security issues at each network layer and choose appropriate countermeasure solutions (including relevant cryptographic mechanisms).

These objectives emphasize not only factual knowledge of networking concepts but also analytical skills – applying algorithms, evaluating protocol behavior, and addressing security concerns – in line with the course’s blend of theory and practice.

Course Schedule and Structure

Course Duration and Contact Hours: The course runs over approximately 8–9 weeks (one academic quarter). It includes two 2-hour lectures per week for most of the quarter, plus weekly laboratory sessions for hands-on exercises. In total, students attend about 16 lectures (spread over 8 weeks, with a mid-term break in the quarter) and engage in lab/tutorial hours each week. The schedule below outlines the progression of topics by week as delivered in a recent edition:

• Week 1: Introduction to Computer Networks – overview of the Internet, network architectures, and the OSI layering model. Begin Data Link layer basics (framing, error detection).
• Week 2: Data Link Layer (continued) – error control and flow control mechanisms. Introduction to the Medium Access Control (MAC) sublayer, focusing on shared channel access principles.
• Week 3: Medium Access Control sublayer – detailed coverage of MAC protocols (e.g. Ethernet CSMA/CD, Wi-Fi CSMA/CA) over multiple lectures. Practical aspects like LAN switching (bridges/switches) are also included.
• Week 4: Network Layer – principles of routing, forwarding, and addressing. Topics include IP protocol (IPv4/IPv6), routing algorithms, and network fragmentation. (This week typically concludes the first half of the course; a midterm exam week with no new lectures may follow, allowing time for self-study and mid-quarter exams in other courses.)
• Week 5: Midterm break – no lectures this week (students use the time for self-study assignments and to consolidate material).
• Week 6: Transport Layer – concepts of end-to-end communication, covering UDP/TCP protocols, reliable data transfer, flow control, and congestion control algorithms.
• Week 7: Transport Layer (cont.) and Network Security – completion of transport layer topics (e.g. TCP congestion control mechanisms) and an introduction to Network Security fundamentals. Security coverage includes basic cryptographic concepts, network vulnerabilities, and defenses at various layers (e.g. TLS, IPsec, wireless security).
• Week 8: Application Layer – common application-layer protocols and paradigms. Topics include DNS, HTTP/HTTPS, email protocols (SMTP/POP3/IMAP), peer-to-peer systems, and content distribution networks. This week often integrates real-world examples of how applications use underlying layers.

Throughout the schedule, the course maintains a top-down approach after the initial overview, roughly aligning each week with one or two layers of the network stack. Lectures are accompanied by shared laboratory sessions where students work on exercises and experiments (e.g. using Wireshark or simple network programming tasks) to reinforce the lecture material in practice.

Textbook Alignment: The official textbook for the course is “Computer Networks” (6th edition) by Tanenbaum, Feamster, and Wetherall. The lecture topics closely follow the textbook’s structure by layers. For example, the Data Link layer lectures (Weeks 1–3) correspond to textbook chapters 3 and 4 (covering link-layer design, error detection, and MAC protocols). The Network layer segment (Week 4) is aligned with chapter 5 (IP networking and routing), while the Transport layer material (Week 6–7) follows chapter 6 (UDP/TCP, congestion control). The Application layer content (Week 8) maps to chapter 7 (covering application protocols like DNS and HTTP). The course’s Security topics draw on chapter 8, which in the 6th edition was substantially updated to focus on network security issues (beyond basic cryptography). In other words, each lecture comes with designated textbook sections for required reading; for instance, the MAC sublayer lectures correspond to sections 4.1–4.4 and 4.7, and the transport layer lectures to sections 6.1–6.5 (with a few advanced subsections omitted). This tight integration ensures that students can reference the book for deeper coverage of each topic discussed in class.

Course Assignments and Assessments

While the final written exam is the only graded component of CSE14B, the course includes a variety of ungraded assignments and learning activities to support student progress. All these components together create a blended learning environment, where students are expected to self-study and practice extensively in addition to attending lectures. Key assessments and assignments are:

• Final Exam (100% of grade): The written end-term exam is the sole determinant of the course grade. It is a closed-book, on-paper exam of 2 hours, during which students may use a basic (non-graphical) calculator but no textbooks or notes. The exam consists of a mix of multiple-choice and open-ended questions, and notably no programming is required on the exam. (There is one resit opportunity offered in the summer for those who do not pass.) The exam’s format and content are described in detail in the next section; in brief, it assesses all the learning objectives through both conceptual questions and problem-solving exercises. Students are provided practice exams (past exam papers) via the course Brightspace to prepare for this assessment.

• Tutorials: The course includes seven tutorial sessions spread across the quarter, designed to practice applying the concepts from lectures. Each tutorial is an ungraded exercise sheet (typically taking about an hour to complete) which students can work on individually or in groups, with teaching assistants available during the shared lab hours to help. The tutorial topics map to the curriculum: e.g. Tutorial 1 covers error detection techniques (building on the Error Detection self-study notes), Tutorial 3 practices sliding window protocols (after the data link/MAC lectures), Tutorial 4 covers network-layer routing tasks, Tutorials 5–6 cover transport-layer problems, and Tutorial 7 deals with cryptography and network security concepts. Solutions are later discussed and posted, so students can learn from any mistakes. These tutorials are highly recommended, as they often provide “deeper insights on algorithms” and are very similar to exam exercises in format and difficulty. In fact, working through the tutorial problems (which involve applying algorithms to toy examples) directly prepares students for the types of open questions encountered in the final exam.

• Programming/Lab Assignments: Each week, students are given a programming or network analysis assignment via the WebLab online platform. These assignments involve hands-on tasks such as using networking tools (e.g. packet sniffing with ) or writing small programs to implement or simulate network algorithms. There is roughly one lab assignment per week (released every Monday) and they are expected to take about each to complete. The lab topics align with the lecture content of that week – for example, early labs may involve examining Ethernet frames or computing error-detection codes, while later labs might involve tinkering with transport protocol behavior. Although these assignments , they serve an important pedagogical purpose: by implementing protocols or analyzing real network traffic, students gain a concrete understanding of how algorithms work in practice. The instructors note that doing the labs reinforces understanding and even helps with exam preparation, as certain implementation details and scenarios explored in labs can appear in exam questions. (To motivate participation, a voluntary “leaderboard” is offered on WebLab, and small incentives like digital stickers were given for completing certain weeks’ labs, but again, there is no direct credit towards the final grade.)

In summary, the only mandatory component is the final exam, but success in that exam is closely tied to engagement with the non-graded components. The course is intentionally designed as a blended learning experience: lectures introduce concepts, self-study notes deepen understanding of special topics, tutorials and labs provide practice in applying knowledge, and the exam then tests both the understanding and the application of all these topics. Students are expected to keep pace with the weekly readings and assignments (see the dependency table for tasks in the course manual) so that they can follow each lecture and be prepared for the cumulative final assessment.

Exam Format and Past Exam Content (Last 3 Years)

The final examination for Computer Networks is a comprehensive test of all course topics, emphasizing both conceptual understanding and analytical problem-solving. The format has been consistent over the last three academic years (2022–2023 through 2024–2025): a 120-minute closed-book written exam comprised of both multiple-choice (MCQ) and open-ended questions. Typically, each exam features around 20 questions total, and these are weighted to sum up to ~20–25 points. For example, the June 2023 exam had 5 multiple-choice and 15 open questions (1 point each, 20 points total) with a passing threshold of 11.5/20 points (≈57.5%). The June 2024 exam contained 20 questions worth 25 points (some open questions carried 2 points) and required about 58% for a pass. The June 2025 exam again had 20 questions (20 points) with a 58% pass mark, maintaining a similar structure. In all cases, students must not only select or write correct answers but often show reasoning: exam instructions explicitly state that open questions should be answered with explanations and any necessary calculations to receive full credit. No external aids are allowed aside from a basic calculator, and the exams are printed (to be answered with pen on a separate answer sheet).

Exam Coverage: The content of the final exam spans the entire course syllabus, and the questions are designed to reflect the learning objectives. Exams from the past three years demonstrate a broad coverage:

• Layered Architecture & Fundamentals: Nearly every exam begins with one or two basic questions to ensure understanding of the network stack. For instance, the 2024 exam asked students to correctly order the seven OSI layers from lowest to highest, and the 2025 exam included a question where students had to name the data unit at each OSI layer (bit, frame, packet, segment, etc.). These are straightforward theoretical questions verifying foundational knowledge.

• Link Layer and MAC: Exams typically include questions about Ethernet, Wi-Fi, and link-layer mechanisms. Multiple-choice conceptual questions have covered scenarios like CSMA/CA collision avoidance: e.g. the 2023 paper presented a Wi-Fi scenario with two stations and asked what happens when RTS/CTS signals collide (requiring understanding of the collision avoidance protocol). Another example is a question on the binary exponential backoff algorithm used in Ethernet’s CSMA/CD, which appeared as a multiple-choice item in 2024. These test students’ conceptual grasp of MAC protocols and why certain algorithms (collision avoidance, backoff, minimum frame size, etc.) are needed. Open questions on this topic have included tasks like explaining why Ethernet frames have a minimum size (to ensure collisions are detected) or computing outcomes of a MAC protocol process (e.g. timeline of transmissions after randomized backoff, as seen in a 2025 question where students determined when a station B can send its frame given backoff times and an ongoing transmission by station A).

• Network Layer: Recent exams often challenge students on IP addressing, routing, and related mechanisms. For example, one question from 2025 asked students to explain in detail how NAT (Network Address Translation) works in a home router, using correct terms (internal/external address and port) – essentially describing how the router rewrites IP addresses and port numbers and maintains a mapping table. Another classic network-layer problem is IP fragmentation: the 2025 exam included a problem where a large IPv4 packet passes through networks with progressively smaller MTUs, and students had to calculate how many fragments would arrive at each stage with and without Path MTU Discovery. Such questions are quantitative and require understanding the fragmentation process (including how fragment sizes are determined and the effect of MTU discovery on avoiding iterative fragmentation). Routing algorithms can also appear – e.g., designing a small network and asking which path a routing algorithm would choose, or conceptual MCQs like identifying what a “hop” means or which fields routers use.

From the above examples, it’s clear the exams cover theoretical, conceptual, and quantitative question types in roughly equal measure:

• Theoretical knowledge questions test basic recall and understanding of definitions or categorical knowledge (e.g. naming layers, definitions of terms like Hamming distance, listing protocol purposes). These ensure mastery of the fundamental vocabulary and facts of networking.

• Conceptual and scenario questions evaluate the student’s deeper understanding of how networks operate in practice. These often present a hypothetical scenario and ask “what happens and why,” requiring the student to apply concepts. Examples include reasoning about a collision in a wireless network, describing NAT behavior in a home router setup, or explaining the effect of a corrupted packet in UDP. Answering these correctly shows that the student can integrate knowledge of protocol mechanisms with real-world conditions. Security scenario questions (like the Tor example or wireless jamming scenario) also fall in this category – they test conceptual insight into system behavior under certain threats or configurations.

• Quantitative and analytical problems require calculation or step-by-step execution of networking algorithms. These include numerical problems like computing checksums or CRC codes, performing binary arithmetic for IP subnetting or fragmentation counts, or deriving an error-correcting code as in the Hamming code exercise. Some quantitative questions are framed as “toy examples” (aligning with the learning objective of applying algorithms to small cases) – for instance, given a short binary message and a generator polynomial, calculate the transmitted CRC bits, or given timing and backoff values, determine when a transmission will occur. These exercises demonstrate the student’s ability to carry out protocol operations correctly and efficiently.

Exam Style and Skills: The exam style favors short-answer understanding over long essays. Even open-ended questions usually expect concise answers focusing on key points (often the answer sheet provides a limited space for each answer). For multiple-choice questions, students must pick the most specific correct answer among alternatives, sometimes requiring careful reading (if multiple answers seem plausible, the instruction is to choose the best one). Partial credit is typically awarded on open questions if the approach is correct but the final answer is slightly off, reflecting an emphasis on method and reasoning. All solutions must be supported: as mentioned, correct reasoning and intermediate calculations are needed for full points. This means that, for example, if asked to compute a CRC or a checksum, writing down the intermediate binary addition or division steps is important, or if explaining a concept like NAT, providing a clear argument of how addresses are translated is expected rather than just a one-word answer.

Over the last three offerings of CSE14B, the exam format and difficulty have remained fairly stable, aligning with the course objectives. Students encounter questions on each layer (including security), roughly mirroring the weight given to those topics in the course. By practicing on the provided tutorial problems and past exams, students can prepare for the mix of question types. In summary, the exam tests a balanced range of skills: it asks students to recall and explain core concepts, to reason about network behavior in context, and to carry out protocol-related computations. This triad of theoretical, conceptual, and quantitative questioning ensures that a passing student has a well-rounded mastery of computer networking fundamentals as taught in CSE14B.