How computers communicate, from the ARPANET to today's Internet

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I’m going to describe how the Internet works, hopefully in human comprehensible terms. I’ll try to explain each technical term as I get to it so you can understand what the technicians are talking about when you need help, and maybe understand what’s happening when you ‘go’ to a website.

To begin, the technology we use to communicate with other computers on the Internet today, is essentially the same as that used on the ARPANET when the technology was first being developed and implemented. I’ll start with explanations of several technical terms related to how your computer connects to a website (using the Google Search AI overview), then I’ll describe what happens when your computer connects with any other computer, including websites on the Internet:

Transmission Control Protocol (TCP) is a core internet protocol ensuring reliable, ordered, and error-checked delivery of data between applications over a network.

Internet Protocol (IP) refers to an IP Address, a unique numerical label assigned to each device on a network (like the internet) for identification and location, similar to a mailing address for data.

Domain Name System (DNS) is the Internet’s phone book, translating human-friendly website names (like https://www.google.com) into machine-readable IP addresses (like 142.250.186.46), allowing browsers to find and connect to the correct servers without users needing to memorize numbers. It’s a hierarchical, distributed system that acts as a critical translation layer, making the internet navigable and accessible for everyone

Internet connection handshaking is the initial digital “hello” where two devices (like your browser and a website server) exchange signals to verify identities, agree on communication rules (speed, encryption), and establish a secure, reliable connection before sending data

When you want to go here, the It’s FOSS Community website, you enter the URL (https://itsfoss.community/) in the address field of your web browser. Your web browser contacts the DNS server designated in your computer’s Network configuration with the URL you’ve specified to get the associated IP address, then it sends a connection request to that IP address. When it receives a positive response, both computers engage in a Hand Shaking procedure to establish how the connection will be made (such as packet size, speed, encryption, etc). After the connection is established, the website sends your browser the content of the file for the web page associated with the IP address to be displayed to you.

At the core of this communication is the TCP protocol, which defines the details of how the packets containing the data being transferred are organized, including the size in bytes of each packet, it’s position in the stream of packets being transferred, and how all this information is organized in the header at the beginning of the packet. Each packet also contains two IP addresses, yours and the websites, so any router or switch between your computer and the It’s FOSS website can know where to forward the packet. How the IP information is organized and used is defined in the IP protocol, and both your computer’s IP address and the destination’s IP address are passed to the TCP layer of your Network connection for insertion into the data packets being transferred.

As I understand it, this is fundamentally what happens when we connect our computers to the It’s FOSS Community forum. It has been a long time since I was in school learning computer science, so while I once knew the layout of a packet header, those details have escaped me over the years. If I’ve gotten anything wrong, please tell me and I’ll make corrections.

Ernie

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Well done Ernie.
What I find particularly satisfying at the moment is that it is all your own thoughts and knowledge. You did NOT copy in a heap of AI generated content.
Maybe I am getting hypersensitive because of recent issues?

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Well, that’s not entirely true. This is all my own thoughts and knowledge, but I did use the AI overview in Google search to make sure I remember correctly, even if I didn’t copy-paste it all. In other words, I used my own knowledge, but for the technical term definitions section, I did double check my work with search terms like “What is [term] n Firefox, using Google search, then I used the over view at the top of my search results to make sure I had my definitions correct, and in two instances, I used them to clarify my own work, so I can’t say I didn’t use AI at all, but at least I didn’t ask it to write this entire thing :slight_smile:

I suppose you could say I used AI as a tool, not a replacement for my lack of knowledge.

Ernie

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Well done.

But you missed a couple of steps from before. If you wanted to add a bit of colour and flavour to it.

I created my first site around 1986 before we had a Internet as such, we used modems to communicate and had to dial a set number which allowed you to access a site. I create a bulletin board all about the ITeC I taught computing and used a BBC b and the pages looked like teletext. Then published an item in a computer journal with our dedicated number.

No way was I the first to do this or claim originality for it but at that time there were only around 100 entrées in the magazines and we were the first post 16 college to do so.

But of course there is even more history other members can add. If of interest.

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There sure is. I used a dial-up modem to download apps posted on a BBS board back when I used MS-DOS 3.1. My computer got hit by a virus from one of those downloads. That taught me a lesson, for sure! I went and got a copy of Norton Antivirus to get rid of the virus, and I’m proud to say that that was the only time I’ve had to deal with anything like that ever since.

Ernie

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I am before you on that MS dos was just a dream we had one icl tower using CCPM (concurrent CPM), another using CPM. But we did all our teaching on BBC computers on a 6502 processor using acorn OS. Shortly after buying a system to run DOS on 8086 processors.

So my bulletin board was hostel on a BBC with no hard disk, just everything loaded from floppy.

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That is a proper use of AI. It is tne modern version of looking up the textbook.

That is a thought… what happens to textbooks now that we have AI… by properly training it with only correct material you could make an AI model that is THE textbook for everything academic. Oh dear, what will become of education.?

Sorry Ernie… highjacking again

You had to have some knowledge to write that.. That is the point. People respect your personal judgement and experience … more so than they do an AI reply or a textbook.

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Very true and correct, cannot beat it with any online tool.

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You do at that, although I did mess around a bit with a Commodore VIC 20, then a C-64 for a few years (combined), but it wasn’t until I saw WordPerfect load onto that IBM-clone my wife and I got so she could do her homework while she was taking a business machines course at a local college that it struck me like “I’ve just gotta know how they did that!”, and so my true love for computers and how they work was born. Since then it has grown into a life-long learning endeavor! :slight_smile:

Ernie

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Exactly the right way to approach linux (or bsd).
There is more to linux/bsd/unix than one can learn in a lifetime.

If someone just wants to learn how to browse and email, they might as well stay with Android or Win or Apple.

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I hope that it evolves!

No worries! :slight_smile:

‘Blushing’ Thank you for that, but all I try to do is relate my experiences, and help others when I find that I understand some concept. When I was the one learning most everything about just owning a computer, let alone doing much with one, I still remember how so many of the so-called gurus always seemed so condescending, and sometimes even abusive, when answering anyone’s questions on the BBSes, and later on Internet forums, and I don’t ever want to be like that …

Ernie

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Never on my wish list. No reason just not as popular. I always fancied a Tandy vomputer but found not afford one or justify. For my wife I bought a apple LC III as her original SE was struggling to do some tasks.

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I understand that. My brother was the C64 lover, and he gave us one for Christmas one year. My boys really enjoyed it, and so did I to a slightly lesser extent. It was a really great gaming platform for that time …

Isn’t it interesting how the history of Networking brings out our memories of using that technology and the associated devices such as the computer we all used? It never ceases to amaze me at the broad spectrum of knowledge and interests we all have to offer!

Ernie

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What I was really alluding to when I mentioned the fact that the Networking system we use today was originally developed and implemented for the ARPANET, was how well thought out and implemented it was because we can still use the same technologies today that were developed so long ago, and how well they have stood up to, and evolve with the ever changing technologies they support.

Ernie

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Let me add a Well Done too.

I thought the write up was thoughtful and nicely presented. It even brought back some of my memories of the actual modem days. It was sometime in the early to mid 80’s when I got my first home computer which was an Atari 400.

I remember hearing the noise the modem made while making the connection and my first modem only connected at 600 bps. In the late 90’s I had my modem requesting the max baud rate of 56k. After all the noise and the connection was established the connection was sometimes at 48K or below. If the connect speed dropped below 32K, I would hang up and try the connection again.

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I remember that ‘noise’ too, and as I saw it, the ‘voice’ of my computer talking to a BBSes, then later, to my ISP’s computer, in their native language, to set up our connection so I could access a BBS, or later, surf the digital highway. My earliest modem days involved ‘calling’ BBSes, each with it’s own phone number, to peruse the new posts, then in a short time, signing up with a local ISP so I could dial in to surf the new digital highway they were beginning to call the Internet. That 56K Ethernet adapter was my first connection to all the websites on the Internet throughout most of my Windows 95 days, and most of which were created and maintained by people who did what they did because they were pretty much driven to do so. In a lot of ways, I dearly miss those days …

Ernie

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The original story was it said hello, but thats fine in english, but does it say bonjour if done in french….. ok i joke

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I get the joke, :slight_smile: but what really happens is when you give your web browser a URL in the address bar, it sends a connect request, then the handshaking process begins, so while the initial request is considered saying hello, it’s done in the native language established in the TCP/IP protocols as are all communications between computers that use them, regardless where the connected devices are located.

Incidentally, these same communication codes have been used since the protocols were originally established. The only difference between phone modems and Network adapters is how the digital data is transmitted/received. Today, digital data, and all communications is sent in digital format over lines designed for that purpose, but the phone modem handles the data by modulating the digital ones and zeros of binary data into analog frequency tones that can be reliably sent over a telephone line that’s designed for voice communication, so the receiving modem must demodulate those frequency tones back into digital ones and zeros that can be used by computers. This is also why phone modems are so much slower than Network adapters. The process of modulating or demodulating data takes a significant amount of time because the data must be processed one bit at a time.

Ernie

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I dont think you mentioned the ‘packet switching network’ concept.
There once were other types of networks ( eg token ring).
I think packet switching dominated because it dealt better with dropouts.

When I first encountered the internet there was a whole spectrum of different types of network, connected together with bridges. The TCP model gradually came to dominate and the diversity disappeared.

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At different companies we’ve used token ring, arcnet, ethernet, and others. Fun stuff.

Thus, the name modem.

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