How it works ?
When you open a browser and type in https://www.buildaiserver.com, it will send a request to the DNS server to resolve it(www.buildaiserver.com) into IP address. Remember the domain name is just a name for you to remember it easily, the actual communication is happening with IP address. The flow will be just like below.
Your browser -> DNS -> Root DNS -> TLD -> IP of DNS of buildaiserver.com -> return IP of www.buildaiserver.com to your browser.
The above steps are just like to get a mail-to-address, you don’t really connect to the www.buildaiserver.com yet.
Then next step is to go to the IP address you get. When your device sends a request to specific IP, your router/gateway will check its routing table to see if it recognize this IP or not. It will send to next router(default gateway) if it doesn’t recognize the IP. Same process goes on until it can reach the destination IP. There are couple routing table updating protocols such as RIP, OSPF, IS-IS, BGP, IGRP(Cisco), EIGRP(Cisco) for routers to exchange routing information in order to reach the destination quickly.
Why IPv6 ?
As internet information exchange keep expanding, we have so many new applications. We have mobile phones, pads, laptops, desktops, and lots of servers in the internet. The original IPv4(only has 4,294,967,296 IPs but need to deduct private network, broadcast, multicast and reserved section) is not enough to accommodate so many devices. Hence we have IPv6(340,282,366,920,938,463,463,374,607,431,768,211,456 IPs) now. It is far than enough to accommodate all devices.
Technology evolution:
Internet:
- Used landline with modem at 4.8K, 9.6K, 14.4K, 28.8K, and 33.6K bps. You cannot use voice while you are using modem for internet connection. This is a voice only or data only mode.
- ADSL(Asymmetric Digital Subscriber Line) is using same landline but with much much higher transfer speed(up to 3.5M bps upstream and 24M bps downstream) and you can use voice at the same time. The technology is using 0~4K frequency for voice and 25K frequency and up for internet connection.
- FTTH(Fiber To The Home): While there are more and more information/data exchange (for example: upload photos and video clips) in internet, upstream speed is also important to internet users as of now. Hence we have same upstream and downstream speed for internet connection(up to 1G bps both upstream and downstream). Higher connection speed can be provided if there is a need and of course ISP needs to upgrade their equipment as well in order to support 10G or 100G internet connection.
- Leased line, ISDN, ATM and Frame Relay were being used for business internet connection.
Intranet/internet backbone:
Started with 10Mb, 100Mb, 1Gb, 2.5Gb, 5Gb, 10Gb , 40Gb, 100Gb…and now 800Gb is available. Use either cat5e, cat6, cat7 cables or fiber as connection media. Leased line, Frame Relay and ATM are also being used.