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In this section of the course,

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we're going to explore network fundamentals.

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Now, when I mention computer networks,

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you probably have a myriad of different concepts

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that are coming to your mind.

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Maybe you're thinking about your everyday router and switch,

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or maybe you're thinking about your home's wifi network

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that connects you to the server

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that's hosting the videos you're watching right now.

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Networks, however, are not just confined to computers

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or limited just to the internet.

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They encompass a diverse range of connections

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that extend to both the wireless networks

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like wifi and cellular, as well as to wired networks

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with things like ethernet and fiber optic connections.

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Now, networks serve the essential purpose

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of connecting a multitude of devices

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that facilitate a seamless flow of data.

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Take for instance, your smartwatch.

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It communicates to with your smartphone using Bluetooth,

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forming what's known as a personal area network, or a PAN,

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because of the proximity

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between your wrist and your cell phone.

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Now, similarly, the wifi network in your home

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also connects your tablet to the internet

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using a wireless access point,

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which is another form of a network,

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which we call a local area network or LAN.

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Further, we might have a desktop computer

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that connects to a switch,

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and that switch connects to a router,

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and that router connects to a modem,

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and that modem connects you to the internet.

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And all these components are integral parts of your network,

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and they all demonstrate the diversity

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and complexity of even the most basic network architectures

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in our environments today.

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Now, over time, our various types of networks

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have become converged.

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Previously, we had distinct networks

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that served different purposes for different things.

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For example, you had one network

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for your analog telephone phones,

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and you had another one for digital data being sent

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by your computers, and yet another one for video being sent

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to the televisions in our homes.

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But these days, we now have a unified network

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that contains voice, data, and video

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all traveling over a single network connection.

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Modern smartphones are a great example of this

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because you can see that they see everything

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as digital data, whether it's a voice call, a text message,

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your internet browsing, or a video you're streaming

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on that device.

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Now, given our heavy reliance on networks,

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we need to ensure high availability and uptime

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are being considered, and make sure

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that they're of importance to us

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when we're designing our networks.

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Now, when I was working as an IT director,

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my customers expected that we remained 100% uptime.

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Now, this is an unrealistic expectation

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because it implies that my team and I could run our networks

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for years without even one second of downtime,

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and that's really just not possible.

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So instead, we published our service level agreement goal

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as 99.999% uptime for our networks.

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Now, this is commonly referred to as

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the five-nines of availability.

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This standard is not considered to be absolute,

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but it does ensure a remarkable level of reliability

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because it only allows around five minutes

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of downtime each year.

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Now, our challenge as network technicians and administrators

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is to maintain this level of continuous operations

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day after day and year after year.

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Now, as we progress through this course,

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you're going to gain the knowledge needed

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to understand network fundamentals

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and gain the skills needed to troubleshoot issues

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that may arise, because this is essential

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for maintaining your high levels

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of network availability and uptime.

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Now, these days, our corporate networks rely

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on converged network designs

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that can handle diverse activities like file sharing

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and video chatting on platforms like Zoom and FaceTime,

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and using things like browsing Google

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or going to diontraining.com,

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or even utilizing social media platforms like LinkedIn,

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Facebook, TikTok, and other things.

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Or you might be streaming videos like YouTube

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and Disney+ and Netflix.

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All of this can be done

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using the exact same internet connection

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because everything is treated as packets

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inside of a larger IP network.

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Now, this multitude of network traffic, though,

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is constantly evolving with new additions as well,

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and this becomes a significant challenge to us

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as network technicians and administrators.

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We are constantly being expected

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to support an ever-growing range of network traffic

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while maintaining that coveted five-nines of availability.

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So in this section of the course, we're going to start out

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by learning about some network fundamentals.

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Our focus is going to be on Domain 1, networking concepts,

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and Domain 2, network implementation,

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and specifically we'll be looking at Objectives 1.2,

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1.6, and 2.3.

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Objective 1.2 states that you must be able to compare

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and contrast networking appliances,

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applications, and functions.

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Objective 1.6 states that you must be able to compare

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and contrast network topologies architectures and types.

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And Objective 2.3 states that given a scenario,

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you must be able to select

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and configure wireless devices and technologies.

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Now, first we're going to look at the different types

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of network components that are used to create our networks,

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including things like clients and servers and hubs

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and switches and wireless access points and routers

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and firewalls and load balancers and proxies

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and intrusion detection systems

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and intrusion prevention systems,

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and all these other kind of things like that.

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Now, we'll also be covering network resources,

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including a discussion of client server models

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and the peer-to-peer model.

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Next, we'll discuss network geography,

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including the discussion about personal area networks,

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local area networks, campus area networks,

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metropolitan area networks,

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and wide area networks, including their size, scope,

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and appropriate use cases.

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We'll also look at a quick real-world demonstration

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of how these three types of networks are going to be used

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in modern vehicles to maintain our connectivity

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as we're driving down the road.

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After that, we're going to explore wired network topologies

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including point-to-point, ring, bus, star, hub and spoke,

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and mesh topologies.

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Then we'll discuss the different wireless topologies

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that you're going to be exposed to, including ad hoc,

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point-to-point, infrastructure mode,

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and wireless mesh networks.

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Next, we'll cover data center topologies,

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including things like the three-tiered model,

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the collapse core model, the spine and leaf model,

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and the ways traffic is classified as it enters,

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leaves or transmits throughout our data centers.

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Finally, we'll take a short quiz to see

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what you learned in this section of the course

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and review your answers to make sure you know

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why the right answers were right

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and the wrong answers were wrong.

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So if you're ready, let's get started with our coverage

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of network fundamentals in this section of the course.