The Initials of the Internet



Dear Reader,

You have just reached a defining moment in your life. No, don’t look behind you. I’m speaking to YOU!

Don’t skip this page. Because this page is the start of a new direction in your life. A direction where your life will change beyond recognition. But wait a minute. I can see that you’re hopelessly lost and haven’t the foggiest idea of what I’m talking about. So let me start at the very beginning.

I have actually written a book on the subject of the Internet and e-commerce. It’s called The Nuts and Bolts of E-Commerce.

But more than the book, you must understand how it was born.

“People read an item in the papers about Java Beans and wonder whether it was the result of India’s Green Revolution. Thus, it is, that this column was born”

DHRUV NATH

My friend, it was born out of total frustration. That’s right! For years, I have come across normal human beings like you and me, tearing their hair apart, trying to understand how the net and e-commerce worked. Not the techie variety, you understand (the variety who only speaks a dialect of C++), but ordinary men and women like all of us! So, they would hear from their computer-savvy friends how TCP/IP had transformed the world. Without the foggiest notion of whether TCP/IP was a new vaccination or simply the initials of India’s latest satellite in space. Or they would read an item in the papers about Java Beans and wonder whether it was the result of India’s Green Revolution. Or, but you get the message, don’t you. And one fine day, I decided to try and put all these fine men and women out of their misery.

And the book was born.

But this is where the story gets real interesting. One day, Rajeev Narayan, the executive editor of Dataquest, and I were having a quiet beer somewhere in Delhi. (Actually, I was having a Pepsi, but beer sounds a lot manlier!)

Suddenly, Rajeev had a brainwave. “Dhruv, why don’t you carry your message to our readers? The readers of Dataquest? Pick up parts of your book, and let’s publish those parts. You see, I want you to give a message to all those wonderful people who read us–a message that technology CAN be understood. And you don’t have to be a PhD in computer science to do so!” 

Figure 1: Waiting
at a level crossing

I sat up. “Great idea, Rajeev!” We refilled our glasses for the umpteenth time, clicked them, and this column was born.

But before we start, I must mention a couple of things.

First of all, remember that what I’m giving you is a simple explanation of hi-tech issues. In the process, in some cases I’ve even had to oversimplify things–but I’m sure you’ll forgive me for it.

Second, this column is not an exhaustive treatise on Internet technologies. It’s meant to give you a flavor of Internet technologies. If you like that flavor, well, just go out and get the main course–and there’s lots to read, starting, of course, with my own book (modesty was never one of my strengths).

So, go ahead and have fun. And I hope you have as much fun reading the column as I had writing it!

Let’s start with something that is at the heart of the Internet.

Yes, we’re talking about those five cryptic letters–TCP/IP! Just roll them over and over your tongue. Sound great, don’t
they? So let’s get to know them a little better… 

I’m sure you know that when the browser and web server interact, what they are doing is sending information, or a message, from one to the other.

Figure 2:
Converting the train to packets

That’s rather like the telephone, isn’t it–where you pick up the phone and talk to someone on another phone anywhere in the world. So, to understand how communication takes place on the Internet, let’s first understand our good old telephone system.

If you think carefully, there is a very fundamental problem with our phone system. When you call a friend, the telephone network establishes a connection between the two of you. And this connection remains reserved for you till you hang up.

What does this mean? Suppose you were having a fight with your girlfriend or boyfriend and said something really mean to her (or him). The next several seconds are spent in silence–you’re wondering how you had the guts to say something like that, and she (or he) is wondering how to react. So you’re both silent, thinking. But the winner is the telecom department–the phone line is still reserved and you, therefore, have to pay even for the long pauses.

In other words, reserving a connection for two parties wanting to communicate with each other is expensive and a waste of resources. Let’s take another analogy. I’m sure you’ve often been stuck in your Maruti car at a level crossing (if you’re lucky enough to own a Mercedes instead of a Maruti, please loan it to me for a month, so I can check whether the logic still holds).

Now, the great thing about level crossings is that once the gate is closed, it remains closed till the entire train has passed by.

And, if you’re unfortunate enough to arrive just after the gate has been closed, too bad!

So, you sit there in your little Maruti (Figure 1), and curse the 2,000 wagons going past (at least it feels like 2,000).

Now, let me give you some hope. Suppose there was a way of de-coupling the wagons and attaching an engine to each wagon. You would then have trains that would be just a wagon each in length. As long as there are no cars waiting at the level crossing, all these mini trains would pass through one by one. But the moment you come along in your little Maruti (Figure 2), the guard at the level crossing asks the trains to wait just a bit, and opens the gate so as to allow you to go through. He shuts the gate after you’ve passed through and the flow of trains continues. So, the time you spend waiting in your car is minimal.

Figure 3: Packets
travelling over the Internet

Try and understand what we have done here. We have converted the train into a lot of little “packets”, each packet consisting of one wagon and its associated engine. Each packet goes across the track, but if there is someone else wanting to move, he doesn’t have to wait too long (incidentally, that someone is also a packet–in this case a Maruti packet).

Since you are smart, I’m sure you can extend this concept to the Internet!

That’s right. Long messages are split into packets. Each packet has an additional section called the header (like the engine) which contains information such as “which computer sent the packet” and “where does it needs to go”. And each packet moves independently on the Net. No long message is able to hog the Net, so no one is forced to wait forever while someone else is sending a lo-o-o-o-o-o-o-o-ong message. And, of course, it makes optimal use of the network because no one blocks resources (Figure 3).

My friend, let me now share something truly momentous with you. If you have understood this example, you have understood a very fundamental concept on the Internet. And this concept is called Packet Switching. Which forms the core of our five favorite letters–TCP/IP.

But hang on. That’s not all. There’s lots more I need to tell you. But not just yet. For the moment, just savor the excitement of your first brush with TCP/IP. And don’t forget to buy your next issue of Dataquest. After all, we need to meet again, don’t we?

DHRUV NATH
The author is a Professor at MDI, Gurgaon

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