Course and textbook written by Jim Kurose
Textbook: “Computer Networking: A Top-Down Approach” 8th edition
Introduction
What is the internet?
At a basic level, the internet is a network of computing devices. Hosts (or end systems) run applications at the edge of the network.
The network is connected by packet switches (like routers and switches) that transfer packets of data. Physically, the data runs over various links including copper wires, optical fibers, or radio waves.
A network is a collection of devices, packet switches, and links that are managed by some entity.
The internet is a network of managed networks (and internet service providers, ISPs). Standardizing how data is sent helps to streamline processing, sending, and receiving of messages. A protocol specifies a certain way of doing things, more specifically, how data should be sent and received (HTTP, TCP, IP, WiFi, 4G, etc.). These internet standards are legislated by a governing body called the Internet Engineering Task Force (IETF). The standards are written in documents called RFCs (request for comments). Protocols are extremely important and a significant part of the course will be spent understanding protocols.
Protocols define the format of messages, order of messages sent and received among network entities, and actions taken on message transmission and receipt
Viewing the internet as a service, it provides infrastructure for sending and receiving data as well as running applications (email, games, social media). While these applications use the internet, they aren’t typically classified as part of the internet. The various internet protocols are able to integrate with an application using a programming interface which gives applications certain primitives for connecting to the network.