[udemy]WebDevelopment_How the Internet Works

Browsing the web

Enter google.com, who is this google.com

This question gets asked all the way down to our ISP(Internet Service Provider), like Verizon For users, you pay so you have internet.

ISP get the request and send them to DNS(Domain Name Server) server, it's like a phone book.

It has the list of all these URLs like google.com and has the address of them

DNS send off the request back through ISP

web browser like google chrome in this case gets 172.217.7.23

we recevie IP address

anything that's connected to the Internet has its own address (each laptop work now has IP address)

this Ip address allows the Internet to work

once we know the IP address, the browser sends off another request to Google Server

Google Server say, oh np let me give you my HTML, CSS, JS

then  HTML, CSS, JS would be sent to the browser

Then browser would show the formal Google page

对于以上三步，

我们是否可以skip第一步

用第二步直接将IP address发送给Google server

同样可以得到第三步的formal Google page

Breaking Google

通过 View ->   Developer -> Develper Tools

界面就变这样了

点击左上方的这个带poniter的标志

可以看到网页的各个模块, 可以自行改动模块

这就像我们改动了Google Server先前传过来的 HTML, CSS, JS文件

一旦我们再reques Google Server

则界面又会复原成Google Server 传来的 HTML, CSS, JS文件所展示的样子（如下图）

 The Internet Backbone 

We have Wifi from router

Router is connected to modem(If you sign up for Internet, you may have someone come to your house and install it

The modem has the signal towers that transmit signals

Is connected all the way to the ISP

IPS is connected to Internet backbone

all the files would go through this submarine cable(physical cable goes the bottom of see floor )

Traceroute

 

通过traceroute可以查到从自己家的home router出发到google server中间转战了多少个stop

Developer Fundamental

how to make websites load faster ?

location of server 越近越好

how many trips 越少越好

size of files 越小越好

What does a developer do ?