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Wyatt's Notes — University

Computer Networks

Computer Networks

Computer networks enable the exchange of data between devices across local and wide areas. The study of networking is organised around layered models, such as the OSI seven-layer model and the TCP/IP model, which decompose communication into modular, independent components. Each layer provides services to the layer above while abstracting the implementation details of the layer below.

Key Concepts

The TCP/IP model defines four layers: link, internet, transport, and application. The internet layer handles routing and addressing via IP, while the transport layer provides reliable (TCP) or unreliable (UDP) end-to-end delivery. Understanding encapsulation, where each layer adds its own header to the data, is fundamental to diagnosing network issues and designing protocols.

Contents

  1. Network Models
  2. Physical Layer
  3. Data Link Layer
  4. Network Layer
  5. Transport Layer
  6. Application Layer
  7. Network Security
  8. Problem Set

Overview

University-level computer networks notes covering protocols, architecture, and security.

Topics Covered

  • Network Models: OSI, TCP/IP, protocol stacks
  • Physical and Data Link: Transmission, framing, error detection
  • Network Layer: IP addressing, routing algorithms, DNS
  • Transport Layer: TCP, UDP, flow control, congestion control

Prerequisites

  • Basic programming experience
  • Understanding of binary representation
  • Familiarity with client-server architecture

How to Use These Notes

Start with network models to understand the layered approach, then progress to each layer in detail. Each section includes worked examples and practice problems.

Use the sidebar to browse topics, or start with the introductory pages linked from the sidebar.

Additional Resources

Each section includes:

  • Detailed explanations of key concepts
  • Worked examples with step-by-step solutions
  • Practice problems with answers
  • Common pitfalls and how to avoid them
  • Connections to other areas of computer science

Study Tips

  1. Master the layers: Understand what each layer does and how they interact
  2. Learn protocols: Know the key protocols (TCP, UDP, IP, HTTP, DNS) and their purposes
  3. Practise with tools: Use Wireshark to capture and analyse network traffic
  4. Understand trade-offs: Reliability vs. speed, security vs. performance
  5. Connect to applications: Relate networking concepts to web, email, and streaming