Welcome to a course two, the bits and bytes of computer networking. You might remember me from the lessons on the internet in the first course, but you also might have jumped ahead, in which case, we're meeting for the first time. My name is Victor Escobedo and I'm a corporate operations engineer. My passion for IT began way back when I was nine years old and my dad brought home our first computer. He was a mechanical engineer and started using the computer to help him with this CAD work. This was the first time I was exposed to computers and later realized that you could install new software on it, including computer games. As I tinkered with the computer, shortly to my dad's dismay, I became more and more interested in how it worked and eventually started to open up the case and peek inside. I found pieces that could be removed and even something that shouldn't, learning through trial and error along the way. I couldn't really explain what it was, but I just found the mechanics of how it all worked together so fascinating. Looking back, these were the seeds that inspired my career. But you see where I grew up, going to college and pursuing a career wasn't exactly talked about or heavily encouraged. I'm a first generation Mexican-American and there weren't a lot of people I knew pursuing a career in tech. My friends and family were mostly worrying about graduating high school and making sure they had jobs, not really thinking about longer term careers. My school didn't have the resources to offer many technical classes, and even though my father was working in mechanical engineering, computers were a tool to him like a mill, ruler, or hammer. My parents encouraged me to work hard and pursue computers but they couldn't really give me advice about college or a career in tech. To no real fault of their own, they just didn't have the experience necessary. When I decided to go to college, I decided to try my hand at computer science since it could feed my curiosity for how computers worked at a more fundamental level. I realized that having this foundational knowledge really allowed me to understand some of the higher level concepts that were important in a career in IT. So while in school, I took my first job in IT for a small local company. I've been working in IT for 12 years now, with the last seven years being here at Google. I now work on managing deployments of large internal IT projects for the company, applying the knowledge I've picked up over the years in my initial help-desk role, to make sure that I understand how I'm impacting our users and various support teams. In my role as a corporate operations engineer, I'm responsible for understanding the impact of changes on our corporate infrastructure. Because of this, networking skills are critical. I need to understand not just how applications work on a single system, but how they interact with all other systems in the company and even externally. So now that you know a bit about me, let's dig into the bits and bytes of networking. Computers communicate with each other a lot like how humans do. Take verbal communication as an example. Two people need to speak the same language and be able to hear each other to communicate effectively. If there are loud noises, one person might have to ask the other person to repeat themselves. If one person only somewhat understands an idea being explained to them, that person might ask for clarification. One person might address only one other person or they may be speaking to a group. And there's usually a greeting and a way to close the conversation. The point is that humans follow a series of rules when they communicate. And computers have to do the same. This defined set of standards that computers must follow in order to communicate properly is called a protocol. Computer networking is the name we've given to the full scope of how computers communicate with each other. Networking involves ensuring that computers can hear each other, that they speak protocols other computers can understand, that they repeat messages not fully delivered, and a couple other things, just like how humans communicate. There are lots of models used to describe the different layers at play with computer networking. But for this course, we've selected the TCPIP five-layer model. We'll also be touching on the other primary network model, the OSI Model, which has seven layers. If you don't know what these models are or how they work, don't worry. We'll be deep diving into these topics throughout this course. It's super important to know these types of layered models to learn about computer networking because it's a really layered affair. The protocols at each layer carry the ones above them in order to get data from one place to the next. Think of the protocol used to get data from one end of a networking cable to the other. It's totally different from the protocol you use to get data from one side of the planet to the other. But both of these protocols are required to work at the same time in order for things like the internet and business networks to work the way they do. Sometimes, there are problems when computers on the internet or on these business networks try to communicate with each other and often, it's up to an IT support specialist to fix these problems. This is why understanding computer networking is so important. By the end of this course, you'll be able to explain all five layers of our model. Not only that. You'll be able to describe how computers determine where to send their messages and how network services like DNS and DHCP work. You'll also be able to use powerful tools to help you troubleshoot network issues. Are you ready? Let's dive in.