Humans are social animals, the most important thing for the human survival is “Networking”.  Every new technology that springs up to improve the human connection will be embraced with open hands.  Internet was one of them.

January 1 1983 is considered the official birthday of internet, The Internet started in the 1960s as a way for government researchers to share information. Computers in the ’60s were large and immobile and in order to make use of information stored in any one computer, one had to either travel to the site of the computer or have magnetic computer tapes sent through the conventional postal system.

Another catalyst in the formation of the Internet was the heating up of the Cold War. The Soviet Union’s launch of the Sputnik satellite spurred the U.S. Defense Department to consider ways information could still be disseminated even after a nuclear attack. This eventually led to the formation of the ARPANET (Advanced Research Projects Agency Network), the network that ultimately evolved into what we now know as the Internet. ARPANET was a great success but membership was limited to certain academic and research organizations who had contracts with the Defense Department. In response to this, other networks were created to provide information sharing.

January 1, 1983 is considered the official birthday of the Internet. Prior to this, the various computer networks did not have a standard way to communicate with each other. A new communications protocol was established called Transfer Control Protocol/Internetwork Protocol (TCP/IP). This allowed different kinds of computers on different networks to “talk” to each other. ARPANET and the Defense Data Network officially changed to the TCP/IP standard on January 1, 1983, hence the birth of the Internet. All networks could now be connected by a universal language.

Now that we know some history of the internet, lets understand it in a more practical sense.

There are so many tech jargons used in the networking world like IPV4, IPV6, SUBNET, ROUTER, GATEWAY etc.  As a common man, if you did not get a chance to understand these concepts, don’t beat yourself for it, it is not that hard. I will step you through some simple analogies for you to understand them.

Let’s take a company setting for example:

There is a company X, and there are 100 employees are working for it. Each employee has an employee number which identifies the individual specifically. So, any department in your company can identify you with this number.

Consider the same analogy, the company X has 100 computers connected in their internal network (Local area network).  Do you think giving them some specific numbers is a good idea, I guess!

IP address is the one which identifies each device in your company’s local area network. Let’s take a quick look at it.

IP address is numerical based label such as 192.0.2.1 that is connected to a computer network that uses Internet protocol (some rules!) for communication.

There are two types of IP addresses, IPV4 and IPV6 address.

Pause reading for a moment, go to your command prompt, and execute ipconfig, do you see something like this:

The IPV4 address 192.168.1.12 is specific to my device.  But this is just in my local area network, like how we compared the employee number analogy, can you identify yourself in a different company with your employee number?  No, you cannot!

So, the IPV4 address you see up there, is just a means for our local network to identify the device it needs to talk with. In other words, these are called “Private IP address”.

The next interesting question is, how do I communicate with the outside world, if they are private to my network. 

Here’s an analogy to help you get to the solution.

One simple solution is to divide the city into two neighborhoods – A and B. Then assign each of the house’s numbers 1 – 500 in each of the neighborhoods. So even though two houses have the same house number, you can uniquely identify them because they belong to different neighborhoods.

When a package needs to reach a house, you must prefix it with the neighborhood and the house number. E.g., A-100, or B-99, or C-499. And that’s it – you’ve devised a system to address houses uniquely.

This is the same concept that is used to manage addressability on the internet using NAT(Network Address Translation).

Q. So, who does the Network Address Translation?  

A. It’s me the Router

Q. If I just want to talk with another device in my own local network.

A. It’s me the Switch, I can hook you up with the other device without any translation.

So now that we know what a Router and Switch is used for, lets see it in a pictorial representation here:

Here all the four computers are assigned to the private IP address such as 10.0.0.1, 10.0.0.2, 10.0.0.3 & 10.0.0.4 and this private IP address are not writable on the internet ,It means the same address can be used an unlimited number of times on the different network. 

In other words, the same employee number would identify different person in a different company. Simple isn’t it.

Let’s say, device 1 assigned with the private IP address 10.0.0.1 wants to access the internet it will first send a request to the router, your router is going to convert this private IP address into a public address and add a unique port number to it and save this information in its NAT Forwarding Table after that it will forward the request to the internet.

Now with the help of port number it will be easy for the router to remember which device has requested in the packet, when your router receives the reply from the internet it is going to check it’s NAT Forwarding Table and send the reply from the internet to the specific device. The same is true for any of the device in your private network.

So, technically for the internet your fleet of devices in the private network is going to just look like one single device because the internet only knows this single public IP address of your network not the private IP address of devices in a network. NAT facilitates that communication back and forth between your devices and the internet.

Hope this gave you some basic understanding of how your devices are communicating with the internet.  Now let’s quickly clarify the need for translation as well.

IPV4 addresses has a size of 32 bits, which limits the address space to 4294967296 (~4 billion approx.). Today the total number of devices connected to the internet goes beyond 10 billion, without the NAT, we would have run out of the public IPV4 addresses.

To address this problem, the engineers came up with a new IP addressing format, which is called the IPV6. IPv6 protocol, which is 128-bits, consists of eight numbered strings, each containing four characters (alphanumeric), separated by a colon. This gives us an unbelievable amount of unique IP addresses: 340,282,366,920,938,463,463,374,607,431,768,211,456 to be precise. It also assures that we will not run out of unique IP addresses to assign to new devices anytime soon.

The idea of this blog was not to deep dive into networking, but to provide you with some basic understanding of the network involved in your day today life. I hope this was helpful, please subscribe to my blogs to get notified when I post a new one.

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