https://www.bilibili.com/video/av46867893/
input
storage
processing CPU(central processing unit)
output
https://www.bilibili.com/video/av47892907/
2.Wires, Cables & Wifi
Bandwidth
maximum transmission capacity of a device
bit rate
fiber optic
Depending on the bounce angle we can actually multiple bits simultaneously.
Wifi
uses a radio signal to send bits from one place to another
all come down to these ones and zeros being delivered by electronic pulses, light beams, radio waves.
3.IP Addresses
the Internet is really a design philosophy expressed in a set of protocols.
Internet Procotols(IP)
ipv4: 32 bits long, 8 bits for each part
ipv6: 128bit per address
Domain Name System(DNS)
Computer uses DNS to look up domain names and get the associated IP address.
DNS servers are connected in a distributed hierarchy, and are divided into zones.
DNS spoofing match a domain name with wrong IP address.
4.Packets, Routing & Reliability
packet information
Many kinds of digital information can be sent with IP packets.
break it into smaller parts called packets.
Each packet has thr Internet address of where it came from and where it’s going.
Routers keep packets moving through networks smoothly.
Every router keeps track of multiple paths for sending packets, and it chooses the cheapest availble path for each piece of data based on destination IP address for the packet.
fault tolerant ->realiability
Transmission Control Protocol (TCP)
TCP manages the sending and receiving of all data as packets. When packets arrive, TCP does a full inventory and send back acknowledgements of each packet received.
If TCP finds some packets are missing, it won’t sign.
scalable
5. Internet with HTTP & HTML
uniform resource locatir (URL) of website you want to visit.
HyperText Transfer Protocol (HTTP)
the language used to communicate between web browsers and servers.
GET request
Hyper Text Markup Language (HTML) use to tell a web browser how to make a page look.
The text of a web page is included directly in the HTML. Other parts, are separate files with their own URLS that need to be requested.
The browser send separate HTTP requests for each of these and displays them as they arrive.
Browser sends the information in plain text to the web server using an HTTP POST request.
Cookies what websites use to remember who you are.
ID number that remembers who you are.
Information is sent in plain text.
Secure Sockets Layer & Transport Layer Security
(SSL & TLS)
HTTPS (Secure) enusre that your HTTP secure and protected.
Digitial Certificate an official ID card proving that it’s the website it claims to be.
published by certificate authorities.
8.How Internet Works
The Internet is a web of pages connected to each other by hyperlinks.
Search engines are constantly running a program called “spider” that crawls through these web pages to collect information about them. For each page of the spider visits, it records any information it might need for a search by adding it to a special database called a search index.
ranking algorithm “Page Rank”
