Western Founders Network Educational - How the Internet Works

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Introduction

In this section we looking at the evolution in the way we communicate

1. Postal Protocols in Ancient China - Yam Routes Established Across the nation: At it's peak there were 1785 established post offices and 300,000 horses distributed around these offcies. Peak travel time can reach around 400km a day - equal to back and forth trip from London to Toronto

2. Telegraph - Telegraphy is not what would be commonly considered as a "Telegraph"

   • Electrical Telegraph - Five Needle Telegraph vs. Morse Key - employ the use of electro magents - marvelous piece of engineering

3. First look at Internet Protocol Suite - 7 layers of Protocal Stack in the ideal Open System Interconnect Reference Model(meant for teaching and demonstratuion hence the name reference - developed around 1977)

END OF INTRODUCTION

INTERLUDE-Basic Computer Logic

In order to understand the complexity of the computers and network protocols of today, we need to first take a look at binary logic and the simplest logic gates that constructs the Arithemitic Logic Units inside the computer

https://www.youtube.com/watch?v=gI-qXk7XojA : Crash Course - Boolean Algebra & Logic Gates

Understanding this at a transistor level is a different story and will not be discussed here - second || third year Software/Electrical/Computer Engineer stuff

http://nandgame.com/ : Cool Game that lets you construct a ALU units using the simplest logic

https://www.nand2tetris.org/ : if you have a little more time you can play this, building a whole OS from the ground up

https://store.steampowered.com/app/370360/TIS100/ : Repairing an old broken computer, great way to practice logical thinking and learn a thing or two about computer networking

Connecting the Dots

Throught out this workshop, there will be a lot of abstractions given the complexity and scale of the subject discussed, the key here is to gain a high level understanding, don't fret over small techincal details

The gist of it is - everything on the internet is a computer, including a server

https://www.lifewire.com/servers-in-computer-networking-817380

https://www.webopedia.com/Computer_Science/Client_Server_Computing - both links contain excellent laymen explanation

There are many different types of servers and they each function differently, a lot of servers today are running multiple kernels, load balancers, and shells as well as read and write databases all on the same machine. If we ever get to do a cloud computing work shop we can dive deeper into this subject

Live-Drawing Segment 1

Now we switch over to the drawing pad to illustrate the puzzle and iteration problem solving that went into solving the puzzle

• The story of Brad, Chad and Becky and how they talk to each other
• Brad is trying to talk to Becky but he can not reach her - so he tries to talk to her through Chad
• PROBLEM!: Their communication is not secured!

[The Drawings will be updated onto the document]

INTERLUDE-Cryptography 101

The Caesar Cipher is one the first ciphers in the world - used by Julius Caesars messengers to transport intelligence message during war

http://practicalcryptography.com/ciphers/caesar-cipher/ - Introduction and Demo

https://demonstrations.wolfram.com/SimpleCaesarCipher/ - Wolfram Demo of the Cipher

Two Problems with this Code: 1. Becky have to know the key before hand 2. The encryption is over simplistic

Introducing - Public Private Key Encryption

http://cobweb.cs.uga.edu/~dme/csci6300/Encryption/Crypto.html - high leve implementation and demonstration, does not explain the actual mechanism behind this method of encryption

(Rivest–Shamir–Adleman) System of Encryption - generate keys - http://www.csfieldguide.org.nz/en/interactives/rsa-key-generator/index.html

Again this is all abstraction, we do not have the mathmatical tool set or time to deep dive into the math behind this topic

Live-Drawing Segment 2

Now Brad have a secured way of communication through Chad to Becky, we will formalize this abstraction

Brad = End-User Chad = Router Becky = Server

PROBLEM with our abstraction - There are some many more computers in the network

SOLUTION - many more computers, routers, and servers are interconnected(computers make request, router direction request to designated server, server hands back response, response travel back to comuputers through routers) - do you see any similarities?

PROBLEM - how does information need to know where to go?

SOLUTION - DHCP servers, IPv4 Address Protocal

PROBLEM - Too many devices!

SOLUTION - IPv6 Address Protocal

PROBLEM - What if we would like to switch servers? Plus, it is so hard to memorize all the 6 byte addresses for each website.

SOUTION - DNS Systems and Servers(each must register a unique domain)

Quiz: What does the www stand for?

USING ROUTERS LIKE THE ANCIENT CHINESE POST OFFICE WE ARE ALLOWED TO DIRECT, USING FIBRE OPTICS/OTHER PHYSICAL COMMUNICATIONS WE ARE ALLOWED TO TRANPORT DATA AT A EXTREMELY HIGH SPEED, AND USING LOGIC UNITS OF THE COMPUTER WE CAN INTERPRET THESE MESSAGES EASITLY

Who owns all of these routers and who owns all the servers in the world?

Demonstration Time:

Open up command prompt -

Ping: sends four packets to a server and ask for a response

NsLookup: look up the ip address of a particular website or look up the DNS server itself

most interesting one: TRACERT checks over maximum of thirty hops where you request got routed to and reports back

How exactly are information handled?

The envelop excersie - again, this is just an abstraction - Introduction to TCP/IP model packets

TCP/IP(Sequence Number) - ensure proper communication in the right sequence and reassembly, can make request to gurantee delivery

UDP - what if you don't want to ensure gurantee delievery? when would you want to make such a request

Going onto HTTPS

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