This document is a compilation of my notes for COE 768: Computer Networks at TMU. All information comes from my professor’s lectures, as well as the course textbook Computer Networks, 5th Edition, Andrew S. Tanenbaum, David J. Wetherall.

Adam Szava - 2tor.ca

F2023

• Table of Contents

Adam_Szava | Quizlet

Week 1

This section includes both ‘Lecture 1’ and ‘Lecture 2’ PDF content from the course shell.

Introduction

<aside> ➕ Definition (Computer Network)

A computer network is a system that interconnects computing devices for data exchanges and communication.

(the cloud is the network)

</aside>

There are 3 different scales that we talk about networking in:

• Local Area Networks (LANs) for computing systems that link local areas.
  • Home networks are LANs, linking all the devices within a single home (printers, phones, router/switches… defined later)
• Metropolitan Area Networks (MANs) for computing systems that link across entire cities.
• Wide Area Networks (WANs) for computer networks that link across entire countries and/or the world.
  • The Internet (capital I) is an example of a WAN, but it itself is a network of networks consisting of LANs, MANs, and WANs.

When discussing networking, we typically generalize the network connected devices as nodes.

In the following image, you can see the different scales of computer networks.

On the left hand side, we see a set of devices labeled as a LAN, just as an example of internal devices. The green circles can be imagined as there interconnection of local devices in a household.

Fundamental Problems

The following is a list of fundamental problems we need to tackle in computer networking:

1. Reliability
   1. Messages can get corrupted as they go across the network. How do we recover from these errors? We use code to detect and correct errors.
   2. Devices can fail. For this reason there are always multiple routes from your computer to the destination computer.