[{"content":"\rToo lazy to read?\rclick here\rfor the TL;DR\rOSI Model: Standardizing to Communicate After a hiatus of almost a month without new posts here on the blog, I\u0026rsquo;m back. I hope during this time you\u0026rsquo;ve been thinking and reflecting on your \u0026ldquo;wanderings\u0026rdquo; as you navigate the cyber field.\nBy now, you already know that the project\u0026rsquo;s name is a playful reference to the human being as layer 8 of the OSI model. So we\u0026rsquo;ll start from the premise that we already know the 8th layer — even though it doesn\u0026rsquo;t officially exist. Therefore, the moment has come to dive deeper into the OSI model in a playful and understandable way for everyone. So, let\u0026rsquo;s go!\nTo explain this content, I could use several examples, like building a house or manufacturing and delivering a car, but I believe that using the writing of a letter and its delivery to the recipient as an example is the easiest way to understand this standard. History\nIn the early days of computing, each manufacturer had its own way of communicating. Now, let\u0026rsquo;s draw a parallel with sending letters. What was happening was as if each person invented their own way of communicating. If another person tried to read the letter, they wouldn\u0026rsquo;t understand it. Only each writer\u0026rsquo;s own \u0026ldquo;family\u0026rdquo; could understand. Maybe not even that. Bringing it to today, it\u0026rsquo;s as if computer manufacturers like Dell, Lenovo, Vaio, and Acer couldn\u0026rsquo;t communicate with each other. Or if phones made by Apple, Samsung, Motorola, and Nokia couldn\u0026rsquo;t talk to each other. It would be chaos.\nBack then, proprietary networks like IBM\u0026rsquo;s SNA (1974), Digital Equipment Corporation\u0026rsquo;s DECnet (1975), and Xerox\u0026rsquo;s XNS (the basis for Ethernet in 1972) dominated, but they prevented connections with other manufacturers.\nFaced with this, the Open Systems Interconnection (OSI) Model was created by the International Organization for Standardization (ISO) with the goal of standardizing communication between computer networks, solving incompatibilities between the proprietary systems of the time. And that lasts to this day. It was developed in the late 1970s, more precisely in 1977, and published in 1984 as ISO 7498. Building the OSI Model\nAs we saw, the construction of the OSI Model had to achieve a few goals:\nstandardize networks; facilitate communication; allow different devices to talk to each other; and simplify maintenance. Given this, the OSI Model was structured into 7 layers, which are:\nNow, an image of the OSI Model using our letter-sending example:\nUnderstanding the layers Layer 7: Application The application layer is the only one you actually \u0026ldquo;see\u0026rdquo; and use every day: WhatsApp, email, Facebook, Instagram, among others. In a letter, it\u0026rsquo;s the content of the letter.\nLayer 6: Presentation This is the layer that translates languages. When writing the letter, no matter the language, whoever reads it will have the content translated into their own language. Also, the letter has been sealed with a secret code or a stamp so nobody peeks at the content. That\u0026rsquo;s what the presentation layer does: it translates, compresses, and encrypts data.\nLayer 5: Session This layer controls the start, maintenance, and termination of communication. It ensures that two devices know when to start and stop \u0026ldquo;talking.\u0026rdquo;\nLayer 4: Transport Here data begins to be divided into smaller parts. For curiosity\u0026rsquo;s sake, data starts being split into 1,500-byte packets. This is called MTU (Maximum Transmission Unit) and refers to the packet size. The transport layer guarantees correct delivery, the order of information, and error control. Here, the most famous protocols are TCP and UDP. It\u0026rsquo;s worth going a little deeper here. These two protocols are completely opposite: one seeks certainty that the recipient receives all packets (TCP) while the other prioritizes delivery over quality (UDP).\nTransmission Control Protocol (TCP): it\u0026rsquo;s the careful one. It checks if everything arrived, if something is missing, and if resending is necessary. It\u0026rsquo;s like sending important documents via the post office with a delivery confirmation receipt. It\u0026rsquo;s used in chat applications like WhatsApp, Telegram, Facebook, and Instagram, among others.\nUser Datagram Protocol (UDP): it\u0026rsquo;s fast, but less careful. It\u0026rsquo;s used in live streaming, online games, and video calls. When you\u0026rsquo;re watching that football or baseball game, this is the protocol used so the transmission happens without hiccups.\nLayer 3: Network Where should the data go? That question is answered at this layer. If your letter needs to leave Brazil heading to the USA, Israel, or Japan, the routing will happen at this layer. In our analogy, this is the moment the distribution center looks at the ZIP code or address, checks the maps, and decides the best route. This is called IP addressing. It\u0026rsquo;s like a GPS choosing the fastest route between cities. This layer works with routers, IP addresses, and path selection.\nLayer 2: Data Link If the network layer is the GPS that finds the cities, the Data Link layer is the one that knows the city in detail, locating every street and every neighborhood. It\u0026rsquo;s the local mail carrier. This layer organizes communication within the local network. It controls network cards, MAC Addresses (we\u0026rsquo;ll understand what that is later when we study computer parts, but for now, understand it as the unique address of a network card), and switches. By analogy, the IP address here is like the building or city address, and the MAC Address is like the apartment or house number.\nLayer 1: Physical This is the material world. Here we have what actually transports the signals: cables, connectors, Wi-Fi waves, and fiber optics. This layer sends only electrical, light, or radio wave signals. In short: the physical layer is the infrastructure. In our letter-writing-and-sending analogy, this layer is equivalent to the paper and pen. If the paper is wet or the pen fails, communication doesn\u0026rsquo;t even start.\nAnd now: is the OSI Model the only one in the world? The answer is: no. Although the OSI Model is extremely famous, it\u0026rsquo;s not the only existing model. In practice, the modern internet mainly uses another model called the TCP/IP Model.\nSo, we can understand that the OSI Model is the ideal plan of how communication should work, and the TCP/IP Model is how it really works in practice.\nThis TCP/IP Model can also be called the Internet Model or the DoD Model (the TCP/IP model was born from an American military project, DARPANET, in the 1970s, even before the OSI Model).\nSee the image below for a comparison between the OSI Model and the TCP/IP Model:\nEven though there are several other models beyond OSI and TCP/IP, such as IBM SNA, Novell IPX/SPX, AppleTalk, and DECnet, there isn\u0026rsquo;t one model better than another. Their purposes are different. Remember: the OSI Model is a reference model, used for studying, teaching, diagnosing problems, and designing systems, while the TCP/IP Model is the model that actually runs the internet. It wasn\u0026rsquo;t created to be didactic. On the contrary, it was created to work. And it achieved its goal so well that it became the foundation of the entire modern internet.\nConclusion After such a long read, I hope that from today onward you can pause every time you use a device and reflect: what kind of communication is happening here? Which layer? What would it look like in the OSI Model? And in the TCP/IP Model?\nThe main point I want you to take away after reading this post is: you don\u0026rsquo;t need to be a hacker or a tech expert to understand. Everything is achievable. And that\u0026rsquo;s the goal of this project. With each post, we\u0026rsquo;ll learn a little more. See you in the next post. Until next time!\n","permalink":"https://projecthl8.com/en/posts/2026/05/02/","summary":"\u003cp class=\"tldr-hint\"\u003e\r\n    Too lazy to read?\r\n    \u003ca href=\"https://chatgpt.com/?hints=search\u0026amp;q=Please\u0026#43;open\u0026#43;this\u0026#43;URL\u0026#43;with\u0026#43;web\u0026#43;search\u0026#43;and\u0026#43;read\u0026#43;the\u0026#43;full\u0026#43;article%3A\u0026#43;https%3A%2F%2Fprojecthl8.com%2Fen%2Fposts%2F2026%2F05%2F02%2F%0A%0AAfter\u0026#43;reading\u0026#43;the\u0026#43;actual\u0026#43;content\u0026#43;of\u0026#43;the\u0026#43;article%2C\u0026#43;do\u0026#43;the\u0026#43;following%3A%0A1%29\u0026#43;Summarize\u0026#43;the\u0026#43;most\u0026#43;important\u0026#43;points\u0026#43;in\u0026#43;clear\u0026#43;and\u0026#43;concise\u0026#43;topics.%0A2%29\u0026#43;Then\u0026#43;tell\u0026#43;the\u0026#43;reader\u0026#43;what\u0026#43;details%2C\u0026#43;data\u0026#43;and\u0026#43;insights\u0026#43;they\u0026#43;are\u0026#43;missing\u0026#43;by\u0026#43;not\u0026#43;reading\u0026#43;the\u0026#43;full\u0026#43;article.\u0026#43;Be\u0026#43;specific\u0026#43;enough\u0026#43;to\u0026#43;make\u0026#43;them\u0026#43;curious.%0A3%29\u0026#43;Remember\u0026#43;that\u0026#43;they\u0026#43;can\u0026#43;continue\u0026#43;asking\u0026#43;questions\u0026#43;about\u0026#43;the\u0026#43;article\u0026#43;here\u0026#43;in\u0026#43;this\u0026#43;chat.%0A4%29\u0026#43;Suggest\u0026#43;a\u0026#43;good\u0026#43;follow-up\u0026#43;question\u0026#43;they\u0026#43;could\u0026#43;ask\u0026#43;to\u0026#43;get\u0026#43;started.\" target=\"_blank\" rel=\"noopener noreferrer\"\u003eclick here\u003c/a\u003e\r\n    for the TL;DR\r\n  \u003c/p\u003e\n\u003ch1 id=\"osi-model-standardizing-to-communicate\"\u003eOSI Model: Standardizing to Communicate\u003c/h1\u003e\n\u003chr\u003e\n\u003cp\u003eAfter a hiatus of almost a month without new posts here on the blog, I\u0026rsquo;m back. I hope during this time you\u0026rsquo;ve been thinking and reflecting on your \u0026ldquo;wanderings\u0026rdquo; as you navigate the cyber field.\u003c/p\u003e\n\u003cp\u003eBy now, you already know that the project\u0026rsquo;s name is a playful reference to the human being as layer 8 of the OSI model. So we\u0026rsquo;ll start from the premise that we already know the 8th layer — even though it doesn\u0026rsquo;t officially exist. Therefore, the moment has come to dive deeper into the OSI model in a playful and understandable way for everyone. So, let\u0026rsquo;s go!\u003c/p\u003e","title":"OSI Model: Standardizing to Communicate"},{"content":"\rToo lazy to read?\rclick here\rfor the TL;DR\r\u0026ldquo;Existence precedes essence.\u0026rdquo;\nJean-Paul Sartre\nWe couldn’t have started in a better way than by saying this. Make no mistake: the digital world is not exclusionary.\nThe cyber environment has all the characteristics of a highly complex space: it is abstract, even though it has physical elements; it is filled with technical terms and jargon; and for non-English speakers, accessing documentation and using applications can be difficult due to the lack of translation. There are many other barriers that can make it harder — or even prevent — users from feeling comfortable in this “challenging” environment, if we can call it that.\nAs Sartre said, what we do precedes who we are. If you’ve made it this far, you’ve probably already read the “About” page. If not, I recommend that you do — it will be valuable and help guide your journey here on the blog. There, I draw a parallel between the evolution of humanity (and to be clear, this is not about Darwin’s Theory of Evolution) and survival in the Digital Age. Humanity has gone through — and continues to go through, even today — a constant learning process. This learning spans every area of life, and the digital world is no exception. However, our experience in this field is still very limited compared to the empirical knowledge we’ve developed over thousands of years about hunting, feeding ourselves, protecting ourselves, and more. Even if we consider the invention of the calculator by Blaise Pascal in 1642, we are talking about only 384 years. And if we look at modern computing as we know it, we are really talking about developments from the 1930s or 1970s onward. In other words, everything is still very recent.\nBut none of that is an excuse. It’s a matter of interest — and that’s where the key lies. Building mental barriers is easier than facing the unknown. Even without fully understanding what drives technology, we use it constantly. Technology today is widely accessible — unlike something like building a house, where understanding each stage of the process can significantly reduce costs. In construction, you want to ensure the structure will support future plans, that the electrical system can handle new devices, and that the plumbing can meet demand. With technology, none of that is required. You simply go to a store, acquire a device, and start using it. The results are immediate: access to banking apps, email accounts, and the exposure — and often the sharing — of personal life through social media. Everything is right there, in the palm of your hand, often used without much thought.\nNow, let me ask you: do you invite just anyone into your home? Do you use the same key for every lock? Do you leave your doors and windows wide open for anyone to enter? Or leave your car accessible for anyone to use? Of course not. Yet this is exactly what happens in the digital world when it is used without awareness.\nAfter reading this, I invite you to reflect: what does your digital life look like? How strong are your passwords? How are you handling your personal data? Is it protected? And what about your internet connection — who has access to it? Ask yourself these questions, and over time, new ones will arise. Understand this: it is not the answers that move the world, but the questions — as Albert Einstein once said. Step by step, we will learn together, correcting what needs to be corrected and strengthening what needs to be strengthened.\n","permalink":"https://projecthl8.com/en/posts/2026/04/1/","summary":"\u003cp class=\"tldr-hint\"\u003e\r\n    Too lazy to read?\r\n    \u003ca href=\"https://chatgpt.com/?hints=search\u0026amp;q=Please\u0026#43;open\u0026#43;this\u0026#43;URL\u0026#43;with\u0026#43;web\u0026#43;search\u0026#43;and\u0026#43;read\u0026#43;the\u0026#43;full\u0026#43;article%3A\u0026#43;https%3A%2F%2Fprojecthl8.com%2Fen%2Fposts%2F2026%2F04%2F1%2F%0A%0AAfter\u0026#43;reading\u0026#43;the\u0026#43;actual\u0026#43;content\u0026#43;of\u0026#43;the\u0026#43;article%2C\u0026#43;do\u0026#43;the\u0026#43;following%3A%0A1%29\u0026#43;Summarize\u0026#43;the\u0026#43;most\u0026#43;important\u0026#43;points\u0026#43;in\u0026#43;clear\u0026#43;and\u0026#43;concise\u0026#43;topics.%0A2%29\u0026#43;Then\u0026#43;tell\u0026#43;the\u0026#43;reader\u0026#43;what\u0026#43;details%2C\u0026#43;data\u0026#43;and\u0026#43;insights\u0026#43;they\u0026#43;are\u0026#43;missing\u0026#43;by\u0026#43;not\u0026#43;reading\u0026#43;the\u0026#43;full\u0026#43;article.\u0026#43;Be\u0026#43;specific\u0026#43;enough\u0026#43;to\u0026#43;make\u0026#43;them\u0026#43;curious.%0A3%29\u0026#43;Remember\u0026#43;that\u0026#43;they\u0026#43;can\u0026#43;continue\u0026#43;asking\u0026#43;questions\u0026#43;about\u0026#43;the\u0026#43;article\u0026#43;here\u0026#43;in\u0026#43;this\u0026#43;chat.%0A4%29\u0026#43;Suggest\u0026#43;a\u0026#43;good\u0026#43;follow-up\u0026#43;question\u0026#43;they\u0026#43;could\u0026#43;ask\u0026#43;to\u0026#43;get\u0026#43;started.\" target=\"_blank\" rel=\"noopener noreferrer\"\u003eclick here\u003c/a\u003e\r\n    for the TL;DR\r\n  \u003c/p\u003e\n\u003cblockquote\u003e\n\u003cp\u003e\u0026ldquo;\u003cem\u003eExistence precedes essence.\u003c/em\u003e\u0026rdquo;\u003cbr\u003e\nJean-Paul Sartre\u003c/p\u003e\n\u003c/blockquote\u003e\n\u003cp\u003eWe couldn’t have started in a better way than by saying this. Make no mistake: the digital world is not exclusionary.\u003c/p\u003e\n\u003cp\u003eThe cyber environment has all the characteristics of a highly complex space: it is abstract, even though it has physical elements; it is filled with technical terms and jargon; and for non-English speakers, accessing documentation and using applications can be difficult due to the lack of translation. There are many other barriers that can make it harder — or even prevent — users from feeling comfortable in this “challenging” environment, if we can call it that.\u003c/p\u003e","title":"The digital world is for everyone"},{"content":"Helping, Teaching, and Protecting: What Drives Us This project was born from the idea of bringing together everyone who is willing to dedicate themselves to learning in this digital environment. That is where the project name comes from: \u0026ldquo;Project Strengthening Layer 8.\u0026rdquo; Its name humorously references a well-known joke in the cybersecurity field: the problem is always at Layer 8 (to better understand layers, check the blog for the \u0026ldquo;OSI Model\u0026rdquo;). And who is Layer 8? The human being. It is not part of the OSI Model, which has only 7 layers — but it is very much part of the daily life of IT professionals.\nWe can see that, in the cyber world, the human being is the weakest link in the chain. This is widely known. We are not machines: we have emotions, desires, and goals. And that is exactly where the danger lies.\nHumanity took thousands of years to learn how to protect itself, understand dangers and their motivations, and recognize the boundaries between right and wrong. In contrast, the \u0026ldquo;Information Age\u0026rdquo; is extremely recent — it is not even 100 years old. So, if we draw a parallel with our history, computing is still in its infancy.\nTherefore, you will learn with us, in a fun and free way, the fundamentals of Information Technology and how to navigate this world more safely, rather than simply browsing the internet without awareness. While doors and windows in the physical world are locked, those in the cyber world are wide open. With dedication, effort, and commitment, we will reduce this attack surface.\nWelcome to pH.L8 - \u0026ldquo;Project Strengthening Layer 8\u0026rdquo;! Together, we will learn and overcome the fear of navigating this environment, because information technology is truly amazing, and learning never ends.\nMethodology and Learning It is important to note that the publication roadmap will not follow a linear learning path. With each publication, a new topic will be introduced, aligned with a broader study sequence and/or specific moments. Therefore, we will not be bound to a fixed roadmap. Trust the process. Read, study, and only then dive deeper into the subject. Learn the basics and build a solid foundation.\nOriginal Language of the Publications The original language of the publications is 🇧🇷 PT-BR (Brazilian Portuguese). The content will also be available in 🇺🇸 EN-US (American English). In order to optimize the speed between publications, we will use various AI, to perform the translations.\n","permalink":"https://projecthl8.com/en/about/","summary":"\u003ch3 id=\"helping-teaching-and-protecting-what-drives-us\"\u003eHelping, Teaching, and Protecting: What Drives Us\u003c/h3\u003e\n\u003cp\u003eThis project was born from the idea of bringing together everyone who is willing to dedicate themselves to learning in this digital environment. That is where the project name comes from: \u0026ldquo;Project Strengthening Layer 8.\u0026rdquo; Its name humorously references a well-known joke in the cybersecurity field: the problem is always at Layer 8 (to better understand layers, check the blog for the \u0026ldquo;OSI Model\u0026rdquo;). And who is Layer 8? The human being. It is not part of the OSI Model, which has only 7 layers — but it is very much part of the daily life of IT professionals.\u003c/p\u003e","title":"About"},{"content":"For official communications, recruitment proposals, feedback or complaints, please use the channel below.\n📧 Email: contato@projecthl8.com\n","permalink":"https://projecthl8.com/en/contact/","summary":"\u003cp\u003eFor official communications, recruitment proposals, feedback or complaints, please use the channel below.\u003c/p\u003e\n\u003cp\u003e📧 \u003cstrong\u003eEmail:\u003c/strong\u003e \u003ca href=\"mailto:contato@projecthl8.com\"\u003econtato@projecthl8.com\u003c/a\u003e\u003c/p\u003e","title":"Contact"},{"content":"Here you can find useful links related to websites for safe downloads. You can also find alternatives to proprietary software, strengthening the Open Source community:\nAlternativeTo AlternativeTo - Click here for visit the site!\nPrivacy Tools Privacy Tools - Click here for visit the site!\n","permalink":"https://projecthl8.com/en/link/","summary":"\u003cp\u003eHere you can find useful links related to websites for safe downloads. You can also find alternatives to proprietary software, strengthening the Open Source community:\u003c/p\u003e\n\u003col\u003e\n\u003cli\u003e\n\u003cp\u003eAlternativeTo\n\u003ca href=\"https://alternativeto.net/\"\u003eAlternativeTo - Click here for visit the site!\u003c/a\u003e\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003ePrivacy Tools\n\u003ca href=\"https://www.privacytools.io/\"\u003ePrivacy Tools - Click here for visit the site!\u003c/a\u003e\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ol\u003e","title":"Links"}]