DO NOT design your network like this!! // FREE CCNA // EP 6 By NetworkChuck

Hey, I've got a question for you: can your network survive a pug okay? What about a baby if it can't, if you can't afford to lose one link or one switch or one router, you're doing it wrong in this video, I'm going to show you two network architectures that can help make our networks awesome and a huge massive shout out to boson software. They are the official sponsor of this free CCNA series and, if you're, trying to get your CCNA- which I assume is probably a lot of you bosons- has the best labs practice exams and now the best courseware you can find for the CCNA I'm actually giving away three copies of their courseware and labs in the link below so enter that contest. It ends tomorrow, Friday, so hurry up now before I show you what a good network design looks like just a beautiful delicious one. Let me show you a bad one. First, as you're working towards becoming a network engineer, you're going to see some bad networks, and it's your job to identify. Why they're bad and how you can make it good now to find a bad network.

You don't have to look very far. Look in your house, I'm not kidding your home network sucks. No, I know a lot of you probably have an amazing home networking comment below with what you have, but for a lot of you. If you ran a business out of your house, and you use that home network it just die, your business would be dead. Now I say that because a lot of businesses, when they first start out their network, looks very similar to a home network, and they make some big boo-boos, some very big mistakes.

Let me show you what it might look like so network, chuck, coffee, still, a very young small, growing coffee company and let's say I trusted a noob to install my network. I would never do that, but let's say I did very similar to your home network. I'll have a router, although in your home network your router isn't just your router. It's also your switch your modem, even your web, no, not the song a wireless access point. This is a networking.

Video get your head straight. So it's doing a lot, which is a horrible thing. Uh. You don't want to have one device, doing everything, and we'll get into why that's important here in a moment, but for now my coffee company just has the router and my router connects to a switch and honestly for a small business. This is fine.

I've got my computers connected to my switch I'll. Have a WAP the wireless access point connected to it as well, giving me Wi-Fi to all my people, maybe a few phones and then, of course, my server to run my website well hold on a second. My switch only has 24 ports, I'm out of ports. I have more things to connect more computers, more servers. What do I do when I tell my new network engineer to fix it? For me, this is where the noob really screws up.

What does he do? Well, he gets another switch, it's fine. He does a great job getting that here it comes, and then he connects the switch to the switch and then oh hold on. What did you do? What did you do? This is bad I'll, explain why here in a moment and before long, I'm growing I'm going like crazy. So I need to add another switch, so my new network engineer does another switch, and he adds it out here and then he does it again. He connects the switch to that switch.

I'm sure a lot of you. If you know networking, that's probably scaring you. It makes me just have heart palpitations, just thinking about it. This is bad. Now it works.

Don't get me wrong, this totally works, but then this happens. My pug Moses comes over and starts chewing on this cable right here then, suddenly the cable breaks and then what happens. Well. All the device is connected to the switch and this switch they have gone. They can't connect to anything right, they're down this right.

Here is what we call now say it with me. A single point of failure: don't ever have those in your network ever all of these right here are single points of failure, which basically means. If one thing fails, then most of your stuff goes down. Never want to have that. Now again, this design still works.

You might have something like this in your house. There are a lot of businesses that have this, and it works most of the time until something fails in your home. You can afford it to fail, because the worst thing that can happen is you miss an episode of Netflix or worse. You can't watch my next video whatever, but in business that means dollars and cents. That's money time now, I'm showing you this, because you will see this in the wild in the real world, and you have to tell them why it's dumb, and you have to fix it.

So how do we fix this? What do we do? Well, some might think. Well, you know we have those single points of failure. Let's just add another connection. We could do that. Add another cable here, another cable here, that's better, but what? If the switch goes down where this switch goes down, we still have glaring problems, and this is not ideal, which is why we have two designs: we're going to talk about today.

It'll help us become redundant and you'll. Hear that word a lot when you're talking about network design, you want to remove as many single points of failure as you can, so you want to be able to have a cable go down, but things still be up. A switch goes down, but things still be up. Let me show you what that looks like so daisy-chaining, our switches together. Bad, don't do that.

So what do we do? How can we make this better? Well, we could do this watch, let's put the router right here and instead of daisy-chaining, we just connect our switches to the router each one done that was easy, come on chuck you're, making it sound so hard. Well, we're not quite done now. This will work, but it's not ideal. So, for example, my computers, this works great for when they want to get to the internet, because that's what the router is great for layer three, but my computers and my servers aren't just talking to the internet they're talking to each other they're talking on the same network and that's where the router becomes less ideal, and he's not the best guy for the job. So what we want is another switch, but not just any switch.

Oh, you're going to love this. This is something when I found this out. I'm like mind blown, so we're gonna Scotch the router up here for a moment he's still in play, but we're gonna talk about something else here. We're going to bring in this guy right here. What is that? It's a switch, but it's not just any switch.

This. My friends are a multi-layer switch, often referred to as a layer, 3 switch which might sound weird. If you've watched my previous videos, we know that switches they deal with layer, 2, mac addresses and routers deal with layer, 3 IP addresses. What's a layer, 3 switch doing here, that's sci-fi, that's weird! I can't deal with that. No, it's amazing.

It's literally a switch that can deal wit hip addresses and mac addresses. It can do it all, and it's blazing fast and then our multi-layer switch will connect to our router, and we're looking a bit better right now. Aren't we I mean it's really beautiful? If this connection goes down- or this switch goes down, then these two are still up this computer's still up this server's still up it's better right, and I'm sure you're thinking well chuck. We still have this right here. This single point of failure, yeah we'll get to that we're taking baby steps, and you'll encounter this a lot when you design networks for businesses, because designing a network with limited single points of failure can be crazy, expensive.

The more devices you add, the more the bill goes up. So I'll show you how we can fix this single point of failure here in a moment, but just know the more we add, the more it costs you'll have to work with the business and what their budget is now this architecture, this model here, the way we designed our network is called a two-tier architecture. Let me show you the tiers right now. Here's tier number one and tier number, two. The switches in this tier one, are called our access switches, and we'll, we'll call this layer, our access layer, because they give our devices the things we connect to our switches.

You know my cables go hold on things like Raspberry Pi's, giving them access ooh that sound. Let me add a pie in there. Real quick can't have a pie, raspberry pie in my network here. What am I crazy? There we go much better and then our tier two layer, this guy is called our distribution layer and, of course this would be our distribution switch. Why is he called that? Well, because his job is to distribute all the packets all the frames throughout the network.

Like he's it, everything goes through him. If the computer wants to talk to my server, the computer goes access, switch distribution switch down to access switch down to server if he wants to access the internet access switch distribution switch router. Now because everything goes through him, he's got to be pretty bulky. He's gotta, be he's gotta be big. Now.

What do I mean by that? Well think about computers, this Raspberry Pi, while he's awesome, he's not like a computing powerhouse. He's tiny you're, not gonna, be playing Call of Duty on this guy. Well, not yet. We, you never know he's not powerful enough, and the same goes with switches. If he got a tiny little eight port switches, he can only handle so much traffic before he's like I need help, so don't put a tiny little.

Eight port switches and your distribution layer he'll die so in the distribution layer. You'll want a massive switch with a lot of horsepower and just like a computer it'll have more components more expensive hardware to make it faster. Now I've shown you access layer, switches, it's something like this, but distribution layer switches are a whole other beast emphasis on beast. Let me show you one. Real quick here are a list of Cisco switches that could be considered distribution, layer, switches and you've got options and all depends on what you need and really how much you can spend so like right.

Here we have the Cisco catalyst 3850s. They have a very similar form factor to the axis layer switches, but they can handle a lot more. Like look here, 480 gigabits per second on their back plane, which means they can handle that much traffic going through them at once, which is a lot, but of course, if you need more, you can get more. You go to the Cisco catalyst 6500. You got 11.4 terabytes per second or terabits per second, and look at that thing. That's crazy! Look! Look at that guy, and we'll cover more about these guys here in a moment because they can go bigger, and they have a different role.

We'll touch on that here. In a moment now we haven't gone too deep down the Cisco rabbit hole just, yet we will don't worry, so I kind of glossed over what the distribution layer is responsible for it does more than just distribute like. Let's take a field trip over to the boson courseware real quick you'll want to get this stuff. I've got their courseware open. Now, let's learn about the distribution here, real quick! If you want to get this, I got a link below now.

I didn't mention this before, but the distribution layer is sometimes referred to as the aggregation layer. Let me highlight that that's the worst highlighter ever better, okay, but it does things like route filtering, enter, VLAN, routing management, ACLs, IPS security policies, routing because remember they are layer, 3 and then summarization and next hop redundancy. I said a lot of words that we have not covered, yet we will just know that those are the roles that the distribution layer typically has or the ones we give it give to it. Now there is something I skipped over. You may have noticed this, because the distribution layer is the intermediary between the axis layer and the core layer.

What's the core layer, I didn't talk about the core layer. Well, hmm, if I scroll up just a little look at this there's another layer. What is that we'll talk about that right now, we're only looking at the distribution layer and axis layer, which is called the two-tier architecture, and we'll again we'll touch on it here in a moment. Now, let's talk about these other single points of failure, how can we fix things? Well, we can add more devices right like check this out. I can add one more distribution layer switch.

Let me do that scoot him over right here, and we'll connect our switches. So it might look like this. We'll add one more connection, one more connection, one more connection, then, of course we'll connect our switch to the router, and then we even connect our two switches to each other. This is what I'm talking about. We've got two distribution layer switches, no longer a single point of failure.

We've got two links to each switch, that's amazing, and then we have two connections to our router but wait hold on. Furthermore, we still have one router. Furthermore, we can solve that. Let's solve that right now, let's put in one more router, and we'll connect both switches to them. Man look at all that redundancy, it's beautiful, but it's expensive.

This is ideal. A lot of companies aren't willing to pay that much for stuff, because these I mean oh, my gosh, these layer, three switches. They could be like hundreds of thousands of dollars same for the routers. Depending on how big you go. No one said networking is cheap, which is why we make the big bucks.

Now this two-tier architecture isn't the only kid on the block, and let me show you where a three-tier architecture might come into play. Let's say: network shut coffee really just starts booming, like oh, my gosh, and we have to add more buildings just to hold all our people. We have so many people now we have three buildings. Things are booming, it's amazing, but we need to connect our buildings together. So we can, all you know, have a network, that's what we're doing here right all right, let's connect them, so I'll connect.

My multi-layer switch to my multi-layer switch down here. My distribution layer, same thing: let's go over here and let's do it right here, just random, but hey we got connectivity right, but, let's make sure we add in some redundancy we'll also add redundant links, make sure each switch has a connection to each switch and each location has a connection each location. Okay, we did if it's kind of a mess, but we did it. Ah, we have another building coming in okay, get ready guys. I have to hire some more network engineers all right, so let's connect them here.

We go okay. This is getting a little crazy as big as our distribution switches are they're under fire right now. They can't handle all this stuff too many connections they're running out of ports, we're maxing out the bandwidth. What do we do? Let's go with a three-tier architecture. You saw that coming right.

Let's do it get all those connections out of there. Whew stressing me out we're going to add one more layer here. So let's get our routers out of here or scoot it up we're not going to get rid of them, and we'll put our next layer in and this layer will have a beast of a switch. It will also be a layer, 3 switch, but this will be the big, father, he'll, be so powerful, so awesome he can handle all that traffic. This switch is our core switch, and this is our core layer.

Tier 3. , our distribution layer switches will connect up to him in a perfect world. We'd have two of our core because he's the's the main guy, and we connect them up and our cores will be connected to each other, and then we'll connect. Our routers to our core switches- this is a beautiful, lovely campus network design, oh so good, expensive, but good. Okay, now, what's this core layer doing besides just being awesome and powerful and huge, let me show you: let's go look at boson, so the access layer we know he's connecting our devices are: our phones, our computers, everything he's the access layer, distribution.

We just talked about him now, the core layer. What is he doing? Look how short his paragraph is. That is truly sums it up here, he's like that massive guy at the gym. Just over there. Oh, there's grunting.

That's all he does is grunt and lift that's what this guy does he's just fast, he and he's associated with low latency and high reliability. So the core switch is expensive, reliable and beefy, because he is the network backbone and a ton of traffic goes through him. He has to be able to handle a lot the weight of the network's on his shoulders. So this is our Cisco three-tier network design model core distribution access. Now I want to talk real quick about the two tier, the two tier had the core layer gone but no no hold on.

He wasn't gone, he was still there or his role was still there. That just became the job of the distribution layer. Let me show you real, quick scroll down through boson's, amazing courseware and get to the Cisco two-tier network design model notice, what they call it. The collapsed core layer. This model is often referred to as the collapsed core model.

I don't know what happened to my ID there just ignore him, but the functions of the core were collapsed into the distribution layer. So the distribution switches have all the responsibilities of the distribution switches right. They have to do a bunch of the routing, the inter VLAN routing, access, control, lists and such like did. They do a lot, and then they have to also be the backbone of the network. Furthermore, they have to be powerful and crazy, which in most cases is a-okay and fine.

I've seen more collapse core or two-tier models than I've. Seen three-tier is fantastic for what I'm about to show you right now, looking back at our four buildings here, here's our new design with a tier three notice that only one of the buildings has the core layer, the tier three layer and that's the design right. The core layer is the core for the entire campus. So now you can imagine how this might simplify things. Our distribution layers will connect back to our core layers, but just to the core layers, not to each other, with that full nasty mesh like we had before this allows us to scale a lot easier if we have a massive campus.

So this is a bit better. My drawings are horrible. Let me show you a better uh view from Cisco's perspective. Cisco has great documentation, here's how buildings will connect without a core. We.

We just saw this just a mess. It's so not scalable right, it's too complex, but if you scroll down just a little, here's our core, and it solves a problem. It's beautiful a lot more clean. We have our one core, then we have all our tier one and tier twos and our buildings. Now you want to see a core switch and how big it might be.

Looking back at uh, Cisco's, available distribution, and course, which is what this is called, find the best core and distribution switch for you um. If you are on the far right, it's the smaller stuff, you go to the very far left you get bigger and bigger and bigger until you get to the big daddy, the Cisco catalyst 9600 series, this thing's a beast, they're modular, so you can just slide in extra little features and awesomeness they've got redundant everything and look at the available, back plane or bandwidth. It has 25.6 terabits per second, it's pretty crazy. If you want to see one of these actually David bumble and I went to Cisco headquarters in San Jose, and we got to talk with the guys who designed it, they walked us through it. So I got a video below if you want to check that out, actually I'll play a clip right now, dude, and so that's also another future-proof for delivering power.

They had just released it. They, let us take a look at it and play with it crazy. Now, as I mentioned before this model right here, is the one I've seen the most of it's. What I've worked with the most the collapse core, where you have your access layer doing its thing on both sets of uh designs. But then you have your collapse core, the distribution switches, also being the core switches, and then these switches will connect up to your routers when we're looking at tier three, I love looking back at that Cisco example.

This is why you want to have a tier three when you have a bunch of buildings in a campus that all need crazy, high-speed connection to each other, like they're, all in the same building, so we call it a campus and really where we got the term from is like a college campus, a school campus. I went to Cisco's campus, and they have like a bazillion buildings. I got lost multiple times, and they have stuff like this. Furthermore, I mean they invented it right, so they invented it because they probably needed it. But what I found as most companies, I've worked for.

We have one main corporate office, and we had our core distribution switches connecting to our access switches and that's all we needed now. That's just the campus, that's connecting our people and our users in the same building. We have more than that, though. We also have data centers and how we design our data centers. Furthermore, we have cloud and how we design our connections to the cloud.

Furthermore, we have our wan. Furthermore, we have our small office home office. Furthermore, we have our users all kinds of different things. Furthermore, we're going to talk about all those here in the next few episodes. Now I've got some homework for you.

Here's what I want you to do most of you work for a company right. You may be in their it department. You may not be in their it department doesn't matter. What I want you to do is find out what design they have. Is it two-tier? Is it three-tier? Is it some weird tier? I don't know find that out and let us know in the comments below I think they'd be really fun to see everyone's uh design and their network, and that was episode.

Six. Let me know what you think comments below. If you have any questions or just suggestions, let me know or if you need help, let me know as well and by the way did you know, I have a discord community discord's, a place where you can go and get help. I've got about 14 000 people in there right now willing to help you out with whatever you're doing looking for a job need help with CCNA. We got you link below to join that, and did you know I'm on social media? Are you following me on Instagram, Twitter, Facebook LinkedIn everywhere? Well, I am so gone follow um everything is network chuck at network chuck.

I post there sometimes so go follow me sometimes, and if you want to help me, do more of this: creating free training on YouTube, creating low cost courses and other places you can join my membership become part of the team. You can either join through YouTube with the join button below or go sign up, but this is it. Io. I got links below for everything or my Patreon. I got a Patreon as well, oh and don't forget to enter the boron contest, I'm giving away three copies of their net sim for CCNA and their new courseware for CCNA, and it's its amazing.

So uh contest is ending like soon, so you better hurry if you're too late, and you didn't win- no worries, I got a special link below you, get 15 off, so check that out tell them. I sent you. It does help out a lot when you buy their stuff through my links. Okay, yeah! That's all I got I'll catch you guys later.

Source : NetworkChuck