WEBVTT 0:00:02.800000 --> 0:00:08.220000 Hello and welcome to this video titled Network Topology Architectures. 0:00:08.220000 --> 0:00:12.400000 In this video we're going to cover several different types of network 0:00:12.400000 --> 0:00:15.840000 architectures. I'm going to introduce you to some concepts such as two 0:00:15.840000 --> 0:00:18.940000 -tier versus three-tier architectures. 0:00:18.940000 --> 0:00:21.420000 What is a spine leaf architecture? 0:00:21.420000 --> 0:00:24.700000 What type of WAN architectures exist? 0:00:24.700000 --> 0:00:29.380000 What about small office home office architectures and on premise versus 0:00:29.380000 --> 0:00:31.560000 cloud-based architectures? 0:00:31.560000 --> 0:00:34.040000 I'm going to introduce you to the differences in all these and what some 0:00:34.040000 --> 0:00:37.340000 of the characteristics are of each one of these. 0:00:37.340000 --> 0:00:42.600000 So let's start by answering the question, what is meant by a network architecture? 0:00:42.600000 --> 0:00:47.500000 What is that? Well, networks clearly, as you can probably guess by this 0:00:47.500000 --> 0:00:50.480000 point, can be designed in a variety of ways. 0:00:50.480000 --> 0:00:54.620000 Not only do you get to choose what devices you need for your networks, 0:00:54.620000 --> 0:00:58.260000 do I need a switch, do I need a router, do I need a wireless access point, 0:00:58.260000 --> 0:01:02.300000 do I need a controller, how many of these things do I need, but you also 0:01:02.300000 --> 0:01:06.200000 get to choose how these things are interconnected and where within your 0:01:06.200000 --> 0:01:09.580000 company or building are they going to be physically located. 0:01:09.580000 --> 0:01:13.760000 So all of those things will determine what type of network architecture 0:01:13.760000 --> 0:01:19.660000 you use. So depending on your positioning and placement of all these devices, 0:01:19.660000 --> 0:01:23.360000 it will dictate things such as what types of cables you need and where 0:01:23.360000 --> 0:01:26.340000 you need to place those cables and how long they need to be. 0:01:26.340000 --> 0:01:28.660000 Where will the data go? 0:01:28.660000 --> 0:01:33.080000 So when John's laptop is talking to the server that hosts all the files, 0:01:33.080000 --> 0:01:35.620000 what will the path of that data be? 0:01:35.620000 --> 0:01:39.460000 And if that path goes down, is there an alternate or redundant path that 0:01:39.460000 --> 0:01:43.180000 can be used? It will also talk about redundancy. 0:01:43.180000 --> 0:01:46.220000 All these different architectures somehow have more or less redundancy 0:01:46.220000 --> 0:01:50.280000 than others. And in case you're not familiar with that term, what that's 0:01:50.280000 --> 0:01:54.720000 simply referring to is if a path in a network goes down like a cable gets 0:01:54.720000 --> 0:01:58.340000 yanked out, someone accidentally spills coffee in a router or switch and 0:01:58.340000 --> 0:02:03.200000 it's short circuits, I want some alternative path available from my data 0:02:03.200000 --> 0:02:05.280000 to still reach its destination. 0:02:05.280000 --> 0:02:06.500000 That's redundancy. 0:02:06.500000 --> 0:02:11.180000 The more alternative paths you have, the more redundancy you have. 0:02:11.180000 --> 0:02:14.860000 Also, some of these architectures will dictate, do I need to use third 0:02:14.860000 --> 0:02:18.980000 -party services? In other words, can I make the architecture all on my 0:02:18.980000 --> 0:02:23.800000 own, all with my own cabling and my own networking devices? 0:02:23.800000 --> 0:02:27.940000 Or do I need to contract the services, some outside provider to help me 0:02:27.940000 --> 0:02:32.320000 build some or most of the architecture I want to use? 0:02:32.320000 --> 0:02:35.800000 So, let's start by looking at some of these architectures, starting with 0:02:35.800000 --> 0:02:39.400000 two tier versus three tier architectures. 0:02:39.400000 --> 0:02:44.340000 Now, these architectures here typically where you will find them is within 0:02:44.340000 --> 0:02:47.160000 your building. So, we're talking about architectures here that are not 0:02:47.160000 --> 0:02:51.040000 for your house, but for your company. 0:02:51.040000 --> 0:02:55.920000 So, a company's network and these are typically mid to larger size companies 0:02:55.920000 --> 0:02:58.880000 that will implement these type of architectures I'm going to show you 0:02:58.880000 --> 0:03:02.780000 right here. So, these are implemented in your local area network, in your 0:03:02.780000 --> 0:03:05.580000 LAN. Let's start with three tier. 0:03:05.580000 --> 0:03:08.420000 Historically, three tier first came out. 0:03:08.420000 --> 0:03:12.940000 This was the first design methodology for local area networks. 0:03:12.940000 --> 0:03:14.620000 And here's how it worked. 0:03:14.620000 --> 0:03:18.540000 The idea was that we're going to take our network and divide up into three 0:03:18.540000 --> 0:03:19.840000 different tiers. 0:03:19.840000 --> 0:03:23.660000 Each tier is going to have a different name and a different responsibility. 0:03:23.660000 --> 0:03:26.900000 So, the lowest tier is what we call the axis layer. 0:03:26.900000 --> 0:03:32.320000 These are the network devices that are giving my hosts such as my laptops, 0:03:32.320000 --> 0:03:38.460000 my PCs, my servers, my tablets, physical connectivity to the network. 0:03:38.460000 --> 0:03:42.860000 So, whatever the very first networking device is that my laptop, tablet 0:03:42.860000 --> 0:03:48.160000 or PC touches, that device is at the axis layer. 0:03:48.160000 --> 0:03:50.580000 Typically, that's going to be one of two things. 0:03:50.580000 --> 0:03:55.760000 It's either going to be network based switches or it's going to be wireless 0:03:55.760000 --> 0:04:00.300000 access. That's what you would typically see at the axis layer. 0:04:00.300000 --> 0:04:05.980000 So, the primary job of the axis layer is, like it sounds, to provide network 0:04:05.980000 --> 0:04:10.820000 access to whatever devices want to connect, and also, possibly to implement 0:04:10.820000 --> 0:04:15.480000 authentication. Make sure that unauthorized devices are not allowed to 0:04:15.480000 --> 0:04:18.020000 connect and gain access to our network. 0:04:18.020000 --> 0:04:24.080000 Now, after that, the next layer up is called the distribution layer. 0:04:24.080000 --> 0:04:28.500000 This would also be composed of either routers or switches that can do 0:04:28.500000 --> 0:04:34.160000 routing. The main idea here is that the axis layer, we may have grouped 0:04:34.160000 --> 0:04:38.060000 together our hosts into different groups, such as maybe this group of 0:04:38.060000 --> 0:04:40.300000 hosts here is in the HR department. 0:04:40.300000 --> 0:04:46.960000 This guy over here is in marketing. 0:04:46.960000 --> 0:04:53.340000 If HR wants to send data to this marketing server, the access layer devices 0:04:53.340000 --> 0:04:55.480000 might not know what that grouping looks like. 0:04:55.480000 --> 0:04:59.260000 They might not know how to get data from one group to the other, but the 0:04:59.260000 --> 0:05:01.440000 distribution layer will. 0:05:01.440000 --> 0:05:05.900000 So, data that needs to go from one segment or one group of the network 0:05:05.900000 --> 0:05:11.120000 to another will pass through the distribution layer and then go back down 0:05:11.120000 --> 0:05:15.480000 again. So, the distribution layer is in charge of routing. 0:05:15.480000 --> 0:05:19.180000 It might also be in charge of security. 0:05:19.180000 --> 0:05:24.180000 For example, if we say, okay, well, HR is allowed to go to marketing, 0:05:24.180000 --> 0:05:27.860000 but HR is not allowed to send data to payroll. 0:05:27.860000 --> 0:05:32.600000 Well, whatever networking security features we implement would be implemented 0:05:32.600000 --> 0:05:36.340000 at the distribution layer to contain that or control that. 0:05:36.340000 --> 0:05:39.780000 And then lastly, in the three layer architecture, we have what's called 0:05:39.780000 --> 0:05:44.660000 the core layer. The idea behind the core layer is that this is a super, 0:05:44.660000 --> 0:05:49.380000 super fast layer that's meant just to get data from like major sections 0:05:49.380000 --> 0:05:52.700000 of our network to other major sections of our network. 0:05:52.700000 --> 0:05:59.040000 So, for example, you might have two buildings, two separate buildings. 0:05:59.040000 --> 0:06:02.680000 Each building has a bunch of access layer devices like switches and wireless 0:06:02.680000 --> 0:06:07.360000 access points. Each building has some stuff at the distribution layer. 0:06:07.360000 --> 0:06:11.340000 So, in building A, any information that has to be routed or sent from 0:06:11.340000 --> 0:06:15.560000 corporate payroll to corporate marketing, both of which is in building 0:06:15.560000 --> 0:06:19.020000 A, would just stay in the distribution and access layer. 0:06:19.020000 --> 0:06:20.460000 It would just stay there. 0:06:20.460000 --> 0:06:25.020000 However, if anybody in building A needs to send data to another group 0:06:25.020000 --> 0:06:28.960000 that's in building B, now we send it all the way to the core layer and 0:06:28.960000 --> 0:06:32.800000 the core layer is responsible for super fast switching of data from one 0:06:32.800000 --> 0:06:33.500000 major section of data. 0:06:33.500000 --> 0:06:36.200000 So, in the other section of the network, like a building to another major 0:06:36.200000 --> 0:06:38.900000 section of the network, like another building. 0:06:38.900000 --> 0:06:43.640000 So, the data should not be slowed down at all in the core layer. 0:06:43.640000 --> 0:06:47.500000 The idea here behind this three layer or three tier model is that there's 0:06:47.500000 --> 0:06:49.200000 going to be any delay in the data. 0:06:49.200000 --> 0:06:51.700000 If there's anything that's going to be slowing it down, it's going to 0:06:51.700000 --> 0:06:54.280000 happen right here at the distribution layer. 0:06:54.280000 --> 0:06:57.600000 Any routing or security features or anything that could potentially slow 0:06:57.600000 --> 0:07:01.300000 the data down where we have to look at the data, inspect the data, make 0:07:01.300000 --> 0:07:05.500000 a decision on the data, would happen right there at the distribution layer. 0:07:05.500000 --> 0:07:09.060000 If data makes its way all the way up to the core layer, these things here 0:07:09.060000 --> 0:07:12.700000 are super, super fast networking devices. 0:07:12.700000 --> 0:07:16.500000 Their job is just to whip stuff across really quickly so that it can go 0:07:16.500000 --> 0:07:19.320000 down again. That's the core layer. 0:07:19.320000 --> 0:07:23.620000 Now, this three layer model, this is how Cisco recommended that networks 0:07:23.620000 --> 0:07:26.420000 be built for a long, long time. 0:07:26.420000 --> 0:07:32.360000 And this is because 20, 30 years ago, there were very distinct, there 0:07:32.360000 --> 0:07:33.680000 were different devices. 0:07:33.680000 --> 0:07:36.660000 You actually had to buy a different type of device to do a core layer 0:07:36.660000 --> 0:07:42.140000 responsibility versus a distribution layer responsibility versus an access 0:07:42.140000 --> 0:07:43.180000 layer responsibility. 0:07:43.180000 --> 0:07:45.480000 You had to buy different devices to do this. 0:07:45.480000 --> 0:07:49.860000 Well, over time, more and more functionality has been built into devices 0:07:49.860000 --> 0:07:54.200000 to where these days, customers say, you know what, I don't need to buy 0:07:54.200000 --> 0:07:59.480000 all this stuff to do the same types of things, the types of operations 0:07:59.480000 --> 0:08:03.560000 that are done at core, distribution or access. 0:08:03.560000 --> 0:08:09.000000 I can actually shrink this down to less layers and accomplish the exact 0:08:09.000000 --> 0:08:13.940000 same thing. And that brings us over to the two tier architecture. 0:08:13.940000 --> 0:08:19.300000 This is also sometimes called the collapsed core architecture. 0:08:19.300000 --> 0:08:23.480000 We don't really necessarily have a name for each layer at this point. 0:08:23.480000 --> 0:08:27.060000 I guess technically you could still say this could still be referred to 0:08:27.060000 --> 0:08:31.740000 as the access layer, possibly because after all, it is giving access to 0:08:31.740000 --> 0:08:33.880000 the network to our hosts. 0:08:33.880000 --> 0:08:38.120000 But the devices right here in layer two, these are actually doing what 0:08:38.120000 --> 0:08:39.400000 this used to do. 0:08:39.400000 --> 0:08:43.860000 So my distribution and core layer are now being handled in just one tier 0:08:43.860000 --> 0:08:50.140000 instead of two. Hence, this is why they call it a two tier architecture. 0:08:50.140000 --> 0:08:54.580000 Now, what are some of the characteristics, regardless of what hardware 0:08:54.580000 --> 0:08:58.680000 you buy or what software you use, what are some of the common characteristics 0:08:58.680000 --> 0:09:02.200000 of two tier or three tier architectures? 0:09:02.200000 --> 0:09:04.460000 Well, there's three things I could think of. 0:09:04.460000 --> 0:09:10.940000 Number one, this type of architecture allows for lots of different types 0:09:10.940000 --> 0:09:13.260000 of things at the access layer. 0:09:13.260000 --> 0:09:18.100000 Because host devices have a variety of ways of connecting to the network. 0:09:18.100000 --> 0:09:21.680000 They might use wired ethernet, in which case a network based switch would 0:09:21.680000 --> 0:09:26.060000 be appropriate. They might use Wi-Fi, in which an access layer switches 0:09:26.060000 --> 0:09:29.660000 appropriate. Hey, they might even use Bluetooth or something else, in 0:09:29.660000 --> 0:09:32.020000 which another device might be appropriate. 0:09:32.020000 --> 0:09:36.080000 So the access layer utilizes several different types of devices, or I 0:09:36.080000 --> 0:09:39.460000 should say could utilize several different types of devices. 0:09:39.460000 --> 0:09:44.820000 In order to accommodate a wide variety of host devices. 0:09:44.820000 --> 0:09:46.440000 Okay, what else? 0:09:46.440000 --> 0:09:49.220000 What else is a common characteristic of this? 0:09:49.220000 --> 0:09:54.760000 Well, a lot of times you will find security implemented here. 0:09:54.760000 --> 0:09:58.820000 At the access layer we might have security protocols that differentiate 0:09:58.820000 --> 0:10:02.020000 who's allowed onto the network and who's not. 0:10:02.020000 --> 0:10:04.560000 That would be a very big concern of these networks. 0:10:04.560000 --> 0:10:09.580000 So in your LANs, a lot of times authentication is done on your access 0:10:09.580000 --> 0:10:14.800000 layer devices. And also another characteristic of this is we want quick 0:10:14.800000 --> 0:10:18.520000 and easy connection to these devices. 0:10:18.520000 --> 0:10:21.400000 So we want to provide very common ports. 0:10:21.400000 --> 0:10:25.200000 We want to make the users connection to the network very easy so they 0:10:25.200000 --> 0:10:27.960000 don't have to jump through a lot of hoops to get onto the network. 0:10:27.960000 --> 0:10:32.580000 So however that's done to make it easy and streamlined would be done at 0:10:32.580000 --> 0:10:34.040000 the access layer. 0:10:34.040000 --> 0:10:41.200000 Alright, so this is for your campus or your enterprise network where your 0:10:41.200000 --> 0:10:42.760000 hosts are going to connect. 0:10:42.760000 --> 0:10:47.320000 Your laptops, your PCs, your wireless devices like your cell phone, your 0:10:47.320000 --> 0:10:50.960000 smart phones and your tablets. 0:10:50.960000 --> 0:10:55.920000 But we also know that a network has another section where all of our file 0:10:55.920000 --> 0:10:59.260000 servers live. And this is what we call our data center. 0:10:59.260000 --> 0:11:01.920000 Our data centers where all our file servers live that have all of our 0:11:01.920000 --> 0:11:03.460000 mission critical data. 0:11:03.460000 --> 0:11:06.620000 So you can sort of think of your network within your company as subdivided 0:11:06.620000 --> 0:11:09.040000 into two main categories. 0:11:09.040000 --> 0:11:13.140000 You've got the campus or enterprise LAN which is all of your hosts live 0:11:13.140000 --> 0:11:16.620000 and the networks used to get data back and forth to them. 0:11:16.620000 --> 0:11:20.520000 But most of the time they're trying to access data in your servers. 0:11:20.520000 --> 0:11:24.700000 And your servers are all over here in a much more secure part of your 0:11:24.700000 --> 0:11:27.180000 network called the data center. 0:11:27.180000 --> 0:11:30.780000 Well the architecture for a data center is not necessarily going to use 0:11:30.780000 --> 0:11:34.420000 this. A data center will use a different type of architecture which we 0:11:34.420000 --> 0:11:37.300000 call a spine leaf architecture. 0:11:37.300000 --> 0:11:43.900000 So when you hear this term spine leaf architecture think data center. 0:11:43.900000 --> 0:11:48.800000 Okay so in a spine leaf architecture interconnections between switches 0:11:48.800000 --> 0:11:51.140000 can be layer two or layer three. 0:11:51.140000 --> 0:11:53.920000 Alright so let's dig into this a little bit more. 0:11:53.920000 --> 0:12:00.660000 First of all what makes this different than what we just saw? 0:12:00.660000 --> 0:12:07.360000 Well number one while of course our ultimate objective is that no part 0:12:07.360000 --> 0:12:09.140000 of the network should ever go down. 0:12:09.140000 --> 0:12:11.820000 We don't want any part of the network to ever go down. 0:12:11.820000 --> 0:12:15.240000 But if you think about it if I'm dividing my network into the data center 0:12:15.240000 --> 0:12:19.500000 which has my mission critical stuff, my data that's stored here and everything 0:12:19.500000 --> 0:12:24.560000 else. If I have to decide between those two my data center is much more 0:12:24.560000 --> 0:12:28.880000 valuable to me. That really can't ever go down. 0:12:28.880000 --> 0:12:31.420000 Yeah I don't want this section over the network over here that's holding 0:12:31.420000 --> 0:12:33.480000 my hosts. I don't want that to go down either. 0:12:33.480000 --> 0:12:37.700000 But if I have to pick between the two I'll spend the bigger bucks, get 0:12:37.700000 --> 0:12:42.820000 the better faster more resilient equipment and put it over here in the 0:12:42.820000 --> 0:12:47.240000 data center. So one characteristic here of spine leaf is that these switches 0:12:47.240000 --> 0:12:51.700000 that you see, these aren't the same switches that your laptops and PCs 0:12:51.700000 --> 0:12:53.080000 are connecting to. 0:12:53.080000 --> 0:12:56.900000 Those are pretty pricey, these are super pricey. 0:12:56.900000 --> 0:13:01.040000 So the switches here in the spine leaf architecture are designed with 0:13:01.040000 --> 0:13:06.280000 the intent and mind of number one providing maximum resiliency and redundancy. 0:13:06.280000 --> 0:13:09.540000 These things are advertised as these will never go down. 0:13:09.540000 --> 0:13:13.020000 You buy one of these things, you can walk away, never have to worry about 0:13:13.020000 --> 0:13:15.700000 it going down. Of course you're going to pay a premium for that because 0:13:15.700000 --> 0:13:19.720000 their power supplies are going to be super expensive to support that. 0:13:19.720000 --> 0:13:23.300000 They'll probably have multiple power supplies in case one goes down, another 0:13:23.300000 --> 0:13:24.860000 one can take up the job. 0:13:24.860000 --> 0:13:27.920000 So they'll have a whole bunch of resiliency and redundancy features built 0:13:27.920000 --> 0:13:31.100000 into them. So that's one thing that makes this architecture different. 0:13:31.100000 --> 0:13:34.760000 Another thing is that because this is where our mission critical data 0:13:34.760000 --> 0:13:38.780000 is, there's a lot of data coming to this spine leaf. 0:13:38.780000 --> 0:13:43.060000 There's a lot of hosts spread throughout our company and all their requests, 0:13:43.060000 --> 0:13:46.240000 all their data is funneling into this. 0:13:46.240000 --> 0:13:50.920000 So these connections have to be super, super fast. 0:13:50.920000 --> 0:13:54.620000 So that's another difference, is in a spine leaf architecture these interconnections 0:13:54.620000 --> 0:13:58.260000 between the switches and the connections leading down to the servers down 0:13:58.260000 --> 0:14:02.640000 below are typically going to be much faster connections than what you 0:14:02.640000 --> 0:14:06.080000 would find in the two tier or three tier, which is also going to drive 0:14:06.080000 --> 0:14:10.240000 up your price. The faster the connections, the more you pay for those 0:14:10.240000 --> 0:14:13.860000 types of ports and interfaces on routers and switches. 0:14:13.860000 --> 0:14:19.840000 So, and then lastly, notice multiple redundant connections here. 0:14:19.840000 --> 0:14:24.420000 Every switch on the bottom has a connection to every switch on the top. 0:14:24.420000 --> 0:14:28.560000 And the idea here is that this type of spine leaf architecture is best 0:14:28.560000 --> 0:14:32.740000 suited for what they call East West traffic. 0:14:32.740000 --> 0:14:37.680000 In other words, traffic that's going like this or going like this or going 0:14:37.680000 --> 0:14:40.460000 like this. This is considered East West traffic. 0:14:40.460000 --> 0:14:43.900000 The idea being that there's not going to be a lot of traffic going north 0:14:43.900000 --> 0:14:48.220000 south. There will be some, but more the traffic is going back and forth 0:14:48.220000 --> 0:14:49.780000 than up and down. 0:14:49.780000 --> 0:14:54.460000 So that's why we have all these redundant connections here between our 0:14:54.460000 --> 0:14:59.260000 spine switches. So these ones here are called our spine switches and these 0:14:59.260000 --> 0:15:02.840000 here are called our leaf switches. 0:15:02.840000 --> 0:15:06.180000 Hence where we get the term spine leaf. 0:15:06.180000 --> 0:15:11.080000 One other thing about this architecture I want you to be aware of, there's 0:15:11.080000 --> 0:15:15.720000 another term for this which is called the fabric. 0:15:15.720000 --> 0:15:18.740000 So if you ever hear somebody saying, oh yeah, my data center, my fabric 0:15:18.740000 --> 0:15:21.280000 is made up of blah, blah, blah, blah, blah. 0:15:21.280000 --> 0:15:25.360000 Well, the fabric, that means they're in a spine leaf architecture. 0:15:25.360000 --> 0:15:30.560000 And the fabric is all these switches, super fast, super redundant, super 0:15:30.560000 --> 0:15:34.320000 expensive switches, which are interconnected in the most redundant way 0:15:34.320000 --> 0:15:41.300000 possible. All right, so that's what you're going to find within your company. 0:15:41.300000 --> 0:15:45.220000 You're going to find a combination of these last three, three tier, two 0:15:45.220000 --> 0:15:48.880000 tier, and spine leaf architectures. 0:15:48.880000 --> 0:15:52.560000 Now chances are though, the data at some point is going to have to leave 0:15:52.560000 --> 0:15:55.820000 your company. You're going to want some data going out to the internet, 0:15:55.820000 --> 0:15:58.740000 or maybe going to a partner's organization that's across the street or 0:15:58.740000 --> 0:16:01.860000 across the city or in another different state or country. 0:16:01.860000 --> 0:16:04.640000 So for that, we need WAN networks. 0:16:04.640000 --> 0:16:08.440000 And just like those different architectures that we can build within our 0:16:08.440000 --> 0:16:12.400000 company, like two tier, three tier, or spine leaf, there are different 0:16:12.400000 --> 0:16:14.560000 WAN architectures as well. 0:16:14.560000 --> 0:16:19.320000 So there's a variety of connection methods, and these basically break 0:16:19.320000 --> 0:16:23.600000 down into three different architectures. 0:16:23.600000 --> 0:16:28.260000 One architecture is point to point, which means that when you select this 0:16:28.260000 --> 0:16:34.460000 architecture, that means you've got, for example, an office maybe in Boston. 0:16:34.460000 --> 0:16:38.300000 And maybe another office in New York City. 0:16:38.300000 --> 0:16:43.980000 If you want a point to point WAN connection between those two, then that 0:16:43.980000 --> 0:16:47.920000 means that your telephone company or whoever sets up the point to point 0:16:47.920000 --> 0:16:51.080000 connection is going to set it up in such a way that when you put data 0:16:51.080000 --> 0:16:56.920000 on this wire right here, there's only one place it could possibly go over 0:16:56.920000 --> 0:16:58.120000 to New York City. 0:16:58.120000 --> 0:17:01.640000 And when he puts data on his wire, there's only one place it could go 0:17:01.640000 --> 0:17:06.900000 over to Boston. There's only two points at the end of this WAN. 0:17:06.900000 --> 0:17:08.060000 Boston, New York City. 0:17:08.060000 --> 0:17:10.280000 That's why they call it point to point. 0:17:10.280000 --> 0:17:13.940000 You say, well, Keith, what other options are there for me for WANs? 0:17:13.940000 --> 0:17:19.960000 Well, you see, the downside to this architecture is if I call it. 0:17:19.960000 --> 0:17:24.320000 So once again, let's say I had Boston here, and I had New York City here. 0:17:24.320000 --> 0:17:28.000000 And if I call up my WAN provider and say, hey, I want another point to 0:17:28.000000 --> 0:17:34.720000 point connection because I got another office coming online in Raleigh, 0:17:34.720000 --> 0:17:39.780000 North Carolina. And I want to connect that up. 0:17:39.780000 --> 0:17:43.180000 Okay, well, point to point means that's going to have to connect up to, 0:17:43.180000 --> 0:17:47.440000 for example, to here to Boston, which means on Boston, I'm going to have 0:17:47.440000 --> 0:17:54.360000 to have two physical cables coming in, and then, that's going to require 0:17:54.360000 --> 0:17:56.280000 another interface on that router. 0:17:56.280000 --> 0:17:59.100000 My Boston router is going to have another available interface with another 0:17:59.100000 --> 0:18:00.580000 cable sticking out of it. 0:18:00.580000 --> 0:18:03.460000 And both these cables are going to terminate like in a wall jack or something 0:18:03.460000 --> 0:18:06.720000 at my office. Point to point. 0:18:06.720000 --> 0:18:10.060000 So more cables, more connections. 0:18:10.060000 --> 0:18:12.020000 Well, what other alternatives do we have? 0:18:12.020000 --> 0:18:16.660000 We also have what's called a broadcast-based WAN. 0:18:16.660000 --> 0:18:20.120000 For example, Metro Ethernet is like this. 0:18:20.120000 --> 0:18:25.520000 With Metro Ethernet, we have a situation where you connect to the WAN 0:18:25.520000 --> 0:18:28.460000 with some sort of a cable. 0:18:28.460000 --> 0:18:31.720000 Okay, it's most likely going to be a fiber optic cable. 0:18:31.720000 --> 0:18:35.280000 So this is a type of cable that's made out of like glass or plastic that's 0:18:35.280000 --> 0:18:38.620000 carrying light. So instead of carrying electrical energy to represent 0:18:38.620000 --> 0:18:43.580000 your data, light, like laser light, is going across that cable to represent 0:18:43.580000 --> 0:18:46.180000 your data. Now, here's the big difference. 0:18:46.180000 --> 0:18:51.600000 In this one right here, once your data gets put onto the fiber ring, everybody 0:18:51.600000 --> 0:18:53.880000 connected to that ring will see it. 0:18:53.880000 --> 0:19:00.020000 So let's say, for example, that in this particular case, customer A was 0:19:00.020000 --> 0:19:02.380000 trying to send data to the ISP. 0:19:02.380000 --> 0:19:05.040000 Well, once customer A puts the data on there and starts going around this 0:19:05.040000 --> 0:19:14.320000 ring, broadcast-based WANs, or even broadcast-based LANs, we'll go to 0:19:14.320000 --> 0:19:20.940000 customer C. That data will also go to customer B as well as going to the 0:19:20.940000 --> 0:19:24.800000 ISP. It'll even circle all around again, and it'll be the job of customer 0:19:24.800000 --> 0:19:28.520000 A to strip that data off the ring, to take it off of there. 0:19:28.520000 --> 0:19:31.180000 That's a broadcast-based WAN. 0:19:31.180000 --> 0:19:33.240000 Now, you might look at that and say, wait a second. 0:19:33.240000 --> 0:19:35.200000 Why would I ever want to use that? 0:19:35.200000 --> 0:19:39.960000 I mean, if I'm customer A, I don't want customer B and C to see my data. 0:19:39.960000 --> 0:19:41.260000 Well, here's the nice thing. 0:19:41.260000 --> 0:19:46.720000 In this type of WAN, these switches that you see connected here, you don't 0:19:46.720000 --> 0:19:48.040000 actually own them. 0:19:48.040000 --> 0:19:50.160000 The ISP owns them. 0:19:50.160000 --> 0:19:53.620000 So all these switches are owned by the ISP, so whoever the building manager 0:19:53.620000 --> 0:19:58.760000 is of this building and this building and this building, they will go 0:19:58.760000 --> 0:20:01.580000 to the ISP and they'll say, hey, we want to connect to your broadcast 0:20:01.580000 --> 0:20:05.160000 -based WAN, your Metro Ethernet ring, for example. 0:20:05.160000 --> 0:20:10.460000 And so the ISP will walk in and put a switch in each one of these locations 0:20:10.460000 --> 0:20:15.400000 that connects up to this WAN, and then you, as the customer, you will 0:20:15.400000 --> 0:20:18.460000 actually be in charge of taking your own network equipment, like maybe 0:20:18.460000 --> 0:20:23.500000 you've got your own switch right here, and you'll connect it to this switch. 0:20:23.500000 --> 0:20:25.260000 Now, I might say, well, how does that help me? 0:20:25.260000 --> 0:20:26.940000 Here's how it helps you. 0:20:26.940000 --> 0:20:32.380000 When your data goes right here and goes onto the WAN, yes, this switch 0:20:32.380000 --> 0:20:34.520000 will see it. So let's just put another switch right here. 0:20:34.520000 --> 0:20:36.740000 So this is actually owned by customer C. 0:20:36.740000 --> 0:20:39.280000 This switch right here is owned by customer B. 0:20:39.280000 --> 0:20:42.180000 This switch right here is owned by customer A. 0:20:42.180000 --> 0:20:44.360000 And here's what's the difference. 0:20:44.360000 --> 0:20:51.280000 Even though this, I'll just say right here, ISP, even though the ISP switch 0:20:51.280000 --> 0:20:56.480000 in this building sees the data, it will recognize, oh, this data is not 0:20:56.480000 --> 0:20:58.720000 actually meant for customer C. 0:20:58.720000 --> 0:21:01.380000 So that data will stop right here. 0:21:01.380000 --> 0:21:07.020000 So whoever, the actual customer who owns customer C switch won't see it. 0:21:07.020000 --> 0:21:09.720000 Only the ISP switch will see it. 0:21:09.720000 --> 0:21:13.240000 And the same thing, when it gets right here, yes, this ISP switch will 0:21:13.240000 --> 0:21:17.020000 see it. But it will say, hey, it's not meant for this building. 0:21:17.020000 --> 0:21:19.440000 So he'll sort of block it right there. 0:21:19.440000 --> 0:21:21.680000 So customer B switch won't see it. 0:21:21.680000 --> 0:21:25.400000 Once it gets over here, this ISP switch will say, oh, yeah, that's for 0:21:25.400000 --> 0:21:28.360000 us. He'll pass it along through. 0:21:28.360000 --> 0:21:32.460000 But it's still called a broadcast based WAN because every device that's 0:21:32.460000 --> 0:21:36.120000 physically connected to it is seeing everything. 0:21:36.120000 --> 0:21:39.880000 It just so happens that in most cases, the device is connected to this 0:21:39.880000 --> 0:21:42.820000 type of WAN are owned by a service provider. 0:21:42.820000 --> 0:21:46.160000 They're just placed in different buildings and sort of leased out or rented 0:21:46.160000 --> 0:21:49.180000 out to different customers. 0:21:49.180000 --> 0:21:53.920000 And then we have another type of WAN called a non-broadcast multi-access 0:21:53.920000 --> 0:22:04.620000 WAN. This is a type of WAN where when you put your data onto it, you actually 0:22:04.620000 --> 0:22:07.540000 address your data in a certain way. 0:22:07.540000 --> 0:22:14.080000 And as that data enters the WAN, it will be kept separate from other people's 0:22:14.080000 --> 0:22:16.700000 data and then go across. 0:22:16.700000 --> 0:22:23.040000 So this is kind of like point to point in that if I had something like 0:22:23.040000 --> 0:22:27.960000 this in point to point, well, any data going across here was never going 0:22:27.960000 --> 0:22:30.080000 to be seen right here. 0:22:30.080000 --> 0:22:31.920000 This guy was never going to see that. 0:22:31.920000 --> 0:22:34.600000 Well, here's the difference. 0:22:34.600000 --> 0:22:39.920000 In point to point WANs, I had to select which interface I wanted. 0:22:39.920000 --> 0:22:43.080000 Did I want to put the data on this interface, which could only go over 0:22:43.080000 --> 0:22:47.280000 here, or do I want to put the data on this interface, which would go right 0:22:47.280000 --> 0:22:52.180000 here? Depending on which interface I selected, that's where the data went. 0:22:52.180000 --> 0:22:59.020000 In a non-broadcast multi-access WAN, I only have one physical connection 0:22:59.020000 --> 0:23:05.520000 to put my data on, but that data is addressed in a certain way that when 0:23:05.520000 --> 0:23:11.580000 it hits the WAN provider, and here's our WAN provider right here, when 0:23:11.580000 --> 0:23:15.980000 it hits the WAN provider, they have some super secret sauce to keep it 0:23:15.980000 --> 0:23:20.280000 separated, so it will only go out to where it needs to go. 0:23:20.280000 --> 0:23:25.780000 My data will never be seen by any other customers because non-broadcast 0:23:25.780000 --> 0:23:30.200000 multi-access will prevent it. 0:23:30.200000 --> 0:23:35.320000 So it's called multi-access because, let's just look at this here for 0:23:35.320000 --> 0:23:42.220000 a second. So if this is the WAN here, this is probably a better picture. 0:23:42.220000 --> 0:23:49.220000 Let's say this is customer A, let's say A has site 1, A has site 2, and 0:23:49.220000 --> 0:23:55.940000 A has site 3. And let's say connected the same WAN is a totally different 0:23:55.940000 --> 0:24:03.000000 company. It's got B1 and B2 connected. 0:24:03.000000 --> 0:24:11.640000 Well, when A1 sends the data, let's say he says, okay, I want this data 0:24:11.640000 --> 0:24:14.340000 to go over to my other site, A2. 0:24:14.340000 --> 0:24:15.860000 That's where I want this to be. 0:24:15.860000 --> 0:24:24.440000 So this data will have a certain address on it, like let's say 101, and 0:24:24.440000 --> 0:24:30.460000 these boxes here represent WAN switches owned by the service provider. 0:24:30.460000 --> 0:24:36.760000 Now, once it hits the WAN switch, that WAN switch will say, oh, 101, that 0:24:36.760000 --> 0:24:41.440000 means I need to switch it out like this way and send it to A2. 0:24:41.440000 --> 0:24:46.880000 So first of all, that data will never pop out here at A3 because that 0:24:46.880000 --> 0:24:48.660000 address didn't send it there. 0:24:48.660000 --> 0:24:54.520000 It'll certainly not pop out here to B2, and it won't pop out here to B1. 0:24:54.520000 --> 0:24:58.000000 The addressing will make sure it goes exactly where it needs to go. 0:24:58.000000 --> 0:25:03.860000 Now, this particular cable right here could be used by other customers 0:25:03.860000 --> 0:25:06.120000 as well, but you don't have to worry about that. 0:25:06.120000 --> 0:25:10.480000 Even though this cable is transporting data from multiple customers, the 0:25:10.480000 --> 0:25:16.240000 addresses in the data itself will keep the data separate and make sure 0:25:16.240000 --> 0:25:19.660000 it never pops out where it's not supposed to go. 0:25:19.660000 --> 0:25:25.400000 So the reason we call this multi-access is because this WAN cloud here 0:25:25.400000 --> 0:25:30.860000 that I've drawn, this thing right here, is a multi-access cloud. 0:25:30.860000 --> 0:25:34.560000 Lots of different devices can connect to it and use it to transport their 0:25:34.560000 --> 0:25:40.120000 data. A1 can use this one connection right here to send data to location 0:25:40.120000 --> 0:25:42.800000 A2 or location A3. 0:25:42.800000 --> 0:25:46.880000 It's not like point-to-point where A1 would need to have two cables, one 0:25:46.880000 --> 0:25:49.820000 cable going to A2, another cable going to A3. 0:25:49.820000 --> 0:25:50.840000 It's not like that. 0:25:50.840000 --> 0:25:55.760000 With multi-access, we've got one cable that we can use to reach multiple 0:25:55.760000 --> 0:25:57.980000 remote locations. 0:25:57.980000 --> 0:26:04.500000 But this is non-broadcast multi-access, meaning there is no way we could 0:26:04.500000 --> 0:26:09.880000 put data on this cable, one piece of data, and have it go out to A2 and 0:26:09.880000 --> 0:26:11.840000 A3 simultaneously. 0:26:11.840000 --> 0:26:15.560000 Can't do that, because when the data puts on this cable, we have to give 0:26:15.560000 --> 0:26:17.440000 it some sort of an address. 0:26:17.440000 --> 0:26:20.200000 The WAN provider will tell you what that address is. 0:26:20.200000 --> 0:26:23.460000 And based on what address you put in that cable, in that data, it's going 0:26:23.460000 --> 0:26:25.820000 to go to one location or another. 0:26:25.820000 --> 0:26:28.800000 Maybe right behind this, I put another piece of data on the exact same 0:26:28.800000 --> 0:26:32.420000 cable, maybe the address for this one is 301. 0:26:32.420000 --> 0:26:36.180000 And when the WAN provider sees that, he knows, oh, okay, that needs to 0:26:36.180000 --> 0:26:38.540000 go to location A3. 0:26:38.540000 --> 0:26:42.780000 So this is non-broadcast multi-access. 0:26:42.780000 --> 0:26:52.640000 Another type of an architecture is a small office, home office. 0:26:52.640000 --> 0:26:54.360000 That's what SoHo stands for. 0:26:54.360000 --> 0:26:56.980000 Here you can see on the left, you've got a small office. 0:26:56.980000 --> 0:26:58.980000 On the right, you've got a home office. 0:26:58.980000 --> 0:27:03.560000 These are typically smaller networks, so we have less equipment demands, 0:27:03.560000 --> 0:27:07.320000 maybe just a single router or a single switch. 0:27:07.320000 --> 0:27:10.540000 And less need for authentication and security, because you're in your 0:27:10.540000 --> 0:27:13.940000 house, you're in your small office, you designed all this. 0:27:13.940000 --> 0:27:16.900000 Very few people or devices are connecting to this. 0:27:16.900000 --> 0:27:21.200000 The downside of this is it's difficult to manage and enforce a policy 0:27:21.200000 --> 0:27:24.100000 from headquarters. 0:27:24.100000 --> 0:27:27.860000 In other words, if I'm at corporate headquarters, I'm the network admin, 0:27:27.860000 --> 0:27:32.660000 and I know that there's like 100 people that are working from home. 0:27:32.660000 --> 0:27:37.360000 So there's 100 home office networks out there connecting back to my corporate 0:27:37.360000 --> 0:27:43.000000 office. And there's like three or four small offices, like maybe branch 0:27:43.000000 --> 0:27:45.020000 offices that are connecting back to me. 0:27:45.020000 --> 0:27:48.240000 It's hard for me to say, okay, here's going to be our policy. 0:27:48.240000 --> 0:27:52.240000 Everybody has to use this kind of authentication, this type of security. 0:27:52.240000 --> 0:27:55.660000 Well, I can say that, but it's hard for me to enforce that, because those 0:27:55.660000 --> 0:28:00.420000 100 people that are working from home, what mechanism do I have to ensure 0:28:00.420000 --> 0:28:04.180000 that they've set up their little tiny network of like maybe one router, 0:28:04.180000 --> 0:28:08.980000 and that's it, with the policy that I've told them they should set up. 0:28:08.980000 --> 0:28:12.600000 Kind of difficult to enforce that. 0:28:12.600000 --> 0:28:17.000000 And the last two architectures I want to talk about are sort of supersets 0:28:17.000000 --> 0:28:22.100000 of the previous architectures we just looked at, on-premises versus cloud 0:28:22.100000 --> 0:28:24.120000 -based architecture. 0:28:24.120000 --> 0:28:29.760000 So an on-premise network, that just simply means that your network and 0:28:29.760000 --> 0:28:34.460000 all the devices, all the resources are right there at your building. 0:28:34.460000 --> 0:28:38.180000 It's on your premises, all the cables, all the switches, all the routers, 0:28:38.180000 --> 0:28:41.120000 all the servers, all the hosts, they're right there. 0:28:41.120000 --> 0:28:43.440000 So you can see everything, you can touch everything, you're in control 0:28:43.440000 --> 0:28:49.280000 of everything. Cloud-based network is a typical type of architecture where 0:28:49.280000 --> 0:28:51.300000 a company might say, you know what? 0:28:51.300000 --> 0:28:58.820000 What we need is like 25 different servers, because we have 25 different 0:28:58.820000 --> 0:29:01.820000 kinds of data that people are needing access in my company. 0:29:01.820000 --> 0:29:08.460000 Well, I could buy the 25 servers myself, then I would be responsible for 0:29:08.460000 --> 0:29:13.220000 finding a place, a physical place in my building to put those things, 0:29:13.220000 --> 0:29:16.140000 making sure I've got enough air conditioning in that room so they don't 0:29:16.140000 --> 0:29:20.360000 overheat, determining the correct cabling to connect them out, then I 0:29:20.360000 --> 0:29:22.580000 got to put the software on there. 0:29:22.580000 --> 0:29:26.620000 If they ever crash, I got to troubleshoot that and fix that, that would 0:29:26.620000 --> 0:29:29.860000 be on-premises. That would all be my responsibility. 0:29:29.860000 --> 0:29:31.560000 Or I could say, you know what? 0:29:31.560000 --> 0:29:36.820000 There's a company out there called Amazon AWS, and they've got servers 0:29:36.820000 --> 0:29:41.400000 I can use. As long as I can get to the internet, I can rent servers from 0:29:41.400000 --> 0:29:46.020000 them. So why don't I take my 25 servers and put them in the cloud instead, 0:29:46.020000 --> 0:29:47.900000 have them reachable via the internet? 0:29:47.900000 --> 0:29:51.580000 Then I don't have to worry about the physical server, AWS, they figure 0:29:51.580000 --> 0:29:55.520000 that out. Amazon, they're responsible for if that server goes down fixing 0:29:55.520000 --> 0:29:58.900000 it, they're responsible for patching it, they're responsible for figuring 0:29:58.900000 --> 0:30:01.440000 out how that server is going to be able to get back to the internet so 0:30:01.440000 --> 0:30:02.720000 I can get to it. 0:30:02.720000 --> 0:30:05.300000 That's a cloud-based network. 0:30:05.300000 --> 0:30:10.200000 So in a cloud-based network, the benefits of that are I could have multiple 0:30:10.200000 --> 0:30:14.420000 offices, each office doesn't have to have their own set of servers, there's 0:30:14.420000 --> 0:30:18.360000 just one common set of servers in the internet hosted by a company like 0:30:18.360000 --> 0:30:22.800000 Amazon, and all my companies can get to those servers as long as they 0:30:22.800000 --> 0:30:24.060000 have internet connectivity. 0:30:24.060000 --> 0:30:27.940000 And it removes a lot of the responsibility from my shoulders and puts 0:30:27.940000 --> 0:30:31.680000 it on the shoulders of the cloud service provider. 0:30:31.680000 --> 0:30:37.020000 So that concludes this video on different network architectures. 0:30:37.020000 --> 0:30:37.940000 I hope you found it useful.