9CSI Flynn's Portfolio - Video Summaries

Video Summaries:

Wires, Cables and WiFi

The internet is like a postal service, unlike postal services however, instead of mail we send bits. Bits can be sent in copper cables, fibre optics and even radio waves. First, we have cables. Using electricity we can send binary over from the sender to the reciever. It's cheap but over a long distance we have significant signal loss. Next, there's fibre optics; little threads of glass used to turn ones and zeroes into light. The downside of working with this however, is it is very expensive and hard to work with. Lastly there are radio waves, used to make the internet wireless. While being good for walking around with the internet at your fingers, radio waves get jumbled over distance.

IP Addresses and DNS

When we send an email, how do we know if it's going to the right place? The answer is simple, IP addresses. IP (internet protocol) addresses are numbers that all devices use to identify each other. Using IP addresses we can make sure when we want to go somewhere on the internet we don't just go onto a random site. But if we use IP adresses to get onto sites, why don't I have to put them in whenever I want to go onto a website? It is because we have something called a DNS. 'Domain Name System' or DNS for short is the reason we don't have to put in the IP address whenever we want to order a pizza online. DNS makes it so we can just put in something like https://sites.google.com/tawacollege.school.nz/8fdellow-9csi/home and it will take us to the address.

Packet, Routers, and Reliability

'The sheer amount of information zooming around the internet is astonishing. But how's it possible for every piece of data to be delivered to you reliably?' This quote came straight from the start of the video. I just had no idea how to start this paragraph. Packets are bits of information used to transfer things like photos and videos. When you send an email, your email gets sent through routers in packets. If one router's broken or something has happened to congest that route, the router will just take another one to send your email to whomever you want to send it to. On to the second part of that starting question. How do you know all the information will arrive reliably? This is where TCPs (transmission control protocol) come in. TCPs make sure if all your packets have arrived. If they're all there the message will be sent and the TCP will approve it. If not, on the other hand, the TCP will request the missing packets from wherever they originated.


With all the information on the internet it is amazing that all these computers can interact with each other at incredible speeds. How is it that you can type in an internet adress and it will send you straight to that website in a matter of seconds? Your computer talks to another one called a server, usually halfway across the world and in milliseconds the server replies in a language called HTTP, (hyper text transfer protocol) the language that one computer says to another. The computer who is requesting the site sends things called "GET requests" simply put they are the words GET and then the file that it is trying to receive. HTML stands for 'Hyper Text Markup Language' and pretty much just tells a page how to look. Sometimes when you send GET requests, you're not just recieving files but also sending them. Like when filling out an e-mail or searching something up.