WEBVTT 1 00:00.000 --> 00:05.100 At this point, we understand how we can communicate between two-fabric edge 2 00:05.100 --> 00:06.340 nodes and between 3 00:06.340 --> 00:09.540 the hosts that are attached to them. 4 00:09.540 --> 00:13.360 But in most of our networks, we're not doing as much East and West traffic, 5 00:13.360 --> 00:14.100 even though 6 00:14.100 --> 00:16.860 that could be very important at the access layer, especially if we're 7 00:16.860 --> 00:18.380 communicating to 8 00:18.380 --> 00:22.330 maybe wireless printers or file servers or even just peer-to-peer 9 00:22.330 --> 00:23.540 communications in 10 00:23.540 --> 00:24.940 certain environments. 11 00:24.940 --> 00:30.130 However, what about if we have North-South traffic, meaning that I'm trying to WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 11 00:24.940 --> 00:30.130 However, what about if we have North-South traffic, meaning that I'm trying to 12 00:30.130 --> 00:30.760 connect 13 00:30.760 --> 00:36.610 up to the internet, which is possible, or I'm simply trying to connect to the 14 00:36.610 --> 00:37.160 rest of 15 00:37.160 --> 00:40.060 my corporate network. 16 00:40.060 --> 00:43.980 Usually I have a lot of corporate network resources that are out there, so 17 00:43.980 --> 00:44.540 trying to 18 00:44.540 --> 00:48.600 communicate maybe to the data center or communicate to other locations. 19 00:48.600 --> 00:51.460 So maybe I'm trying to connect through the WAN. 20 00:51.460 --> 00:58.220 Or for that matter, maybe I'm just trying to connect to other distribution 21 00:58.220 --> 00:58.880 sites and 22 00:58.880 --> 01:01.940 communicate out to those locations. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 22 00:58.880 --> 01:01.940 communicate out to those locations. 23 01:01.940 --> 01:07.750 And so the question is now, how do I handle traffic coming in that's destined 24 01:07.750 --> 01:08.380 for one 25 01:08.380 --> 01:10.380 of these types of locations? 26 01:10.380 --> 01:16.080 We're talking about subnets that do not exist inside of the SDA fabric. 27 01:16.080 --> 01:21.260 So these are non-SDA subnets. 28 01:21.260 --> 01:24.640 Either we're talking about the internet or we're talking about our own networks 29 01:24.640 --> 01:24.820 that 30 01:24.820 --> 01:27.940 just don't exist at this site. 31 01:27.940 --> 01:33.050 When we may recall that this is the responsibility of the border nodes, we're WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 31 01:27.940 --> 01:33.050 When we may recall that this is the responsibility of the border nodes, we're 32 01:33.050 --> 01:34.060 going to deploy 33 01:34.060 --> 01:39.860 border nodes into our environment to connect us out to these different types of 34 01:39.860 --> 01:40.980 networks. 35 01:40.980 --> 01:44.060 And there are actually three different types of border nodes. 36 01:44.060 --> 01:50.930 We have internal border nodes, external border nodes, as well as, well we've 37 01:50.930 --> 01:52.100 got a couple 38 01:52.100 --> 01:54.760 of different words for this in our ways of describing it. 39 01:54.760 --> 01:58.980 We could call it an anywhere border node. 40 01:58.980 --> 02:01.300 This term has become popular. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 40 01:58.980 --> 02:01.300 This term has become popular. 41 02:01.300 --> 02:06.500 Or we could just call it an internal plus external. 42 02:06.500 --> 02:10.150 And occasionally you might hear referred to as a hybrid, but either way we see 43 02:10.150 --> 02:10.580 we have 44 02:10.580 --> 02:14.180 three different types of border nodes. 45 02:14.180 --> 02:16.420 So what are these different types? 46 02:16.420 --> 02:19.060 Well let's start with internal border nodes. 47 02:19.060 --> 02:23.940 The idea of an internal border node would be to connect us to networks such as 48 02:23.940 --> 02:24.460 those 49 02:24.460 --> 02:25.900 on the left. 50 02:25.900 --> 02:30.180 So we have this border node here that is part of the fabric. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 50 02:25.900 --> 02:30.180 So we have this border node here that is part of the fabric. 51 02:30.180 --> 02:36.820 So we're building our VX land tunnels among all of our different edge devices. 52 02:36.820 --> 02:41.300 But the internal border node, just like any other border node, is going to be 53 02:41.300 --> 02:41.740 part of 54 02:41.740 --> 02:43.780 that fabric topology. 55 02:43.780 --> 02:48.050 And so we're communicating with the control plane node and all of these 56 02:48.050 --> 02:50.020 different situations, 57 02:50.020 --> 02:53.740 except now we're no longer trying to register endpoints. 58 02:53.740 --> 03:01.100 I don't have endpoints connecting off of this so much as I have networks. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 58 02:53.740 --> 03:01.100 I don't have endpoints connecting off of this so much as I have networks. 59 03:01.100 --> 03:02.100 And that's what's key. 60 03:02.100 --> 03:08.570 I am not only connecting us to other networks that live within the corporate 61 03:08.570 --> 03:09.660 world, so not 62 03:09.660 --> 03:16.170 out on the internet, but because of this, I'm actually going to register these 63 03:16.170 --> 03:16.620 subnets 64 03:16.620 --> 03:18.140 with the fabric. 65 03:18.140 --> 03:19.740 Well how do we do that? 66 03:19.740 --> 03:24.530 Well we are going to do the onboarding concept, except rather than onboarding 67 03:24.530 --> 03:25.340 one of these 68 03:25.340 --> 03:32.060 endpoints as /32 routes, I'm going to onboard by sending my register message WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 68 03:25.340 --> 03:32.060 endpoints as /32 routes, I'm going to onboard by sending my register message 69 03:32.060 --> 03:33.340 for the actual 70 03:33.340 --> 03:36.820 subnets that I'm learning. 71 03:36.820 --> 03:38.060 Why are we doing this? 72 03:38.060 --> 03:42.870 Well the reason for this is because if I get a packet that is destined for an 73 03:42.870 --> 03:43.580 internal 74 03:43.580 --> 03:49.220 subnet, let's just say it's something in the data center. 75 03:49.220 --> 03:53.410 We're trying to communicate with an application that it lives in one of our 76 03:53.410 --> 03:54.460 data centers. 77 03:54.460 --> 03:57.460 Well at that point, I need to know where to send it. 78 03:57.460 --> 04:01.560 So I'm going to do my check-in with the control plane node, and the control WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 78 03:57.460 --> 04:01.560 So I'm going to do my check-in with the control plane node, and the control 79 04:01.560 --> 04:02.620 plane node needs 80 04:02.620 --> 04:05.940 to check its EID to our locked mappings. 81 04:05.940 --> 04:10.440 Well in this case, it's going to find that the longest prefix match, when we're 82 04:10.440 --> 04:11.100 looking 83 04:11.100 --> 04:16.150 at our endpoint identifiers, we're going to find, maybe this is a /24 subnet up 84 04:16.150 --> 04:18.220 here, 85 04:18.220 --> 04:26.980 so we're going to find that the /24 subnet maps to that internal border node. 86 04:26.980 --> 04:30.410 Because it's mapping to the internal border node, I know that I can send it out WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 86 04:26.980 --> 04:30.410 Because it's mapping to the internal border node, I know that I can send it out 87 04:30.410 --> 04:31.300 the appropriate 88 04:31.300 --> 04:35.580 VXLAN tunnel to get it to where it needs to go. 89 04:35.580 --> 04:40.380 Now the border node, as the name implies, sort of draws this dividing line here 90 04:40.380 --> 04:40.660 . 91 04:40.660 --> 04:47.160 I have the fabric communications internally here, and then I have the rest of 92 04:47.160 --> 04:48.620 the traditional 93 04:48.620 --> 04:51.380 networking world north of here. 94 04:51.380 --> 04:55.340 So we have a dividing line, and yet the internal border node needs to handle 95 04:55.340 --> 04:55.900 both. 96 04:55.900 --> 04:59.630 We need to be registering subnets internally, we need to be encapsulating and 97 04:59.630 --> 05:00.500 de-capsulating WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 97 04:59.630 --> 05:00.500 de-capsulating 98 05:00.500 --> 05:07.550 VXLAN, but we also need to be advertising our fabric routes to the rest of the 99 05:07.550 --> 05:08.820 network, 100 05:08.820 --> 05:13.560 because these routers, these devices up here, they need to know how to get to 101 05:13.560 --> 05:14.620 these hosts. 102 05:14.620 --> 05:18.820 We need to know how to send the return traffic back to the fabric, and so that 103 05:18.820 --> 05:19.500 has to land 104 05:19.500 --> 05:22.820 with our internal border node. 105 05:22.820 --> 05:26.740 So the internal border node is importantly going to be performing the 106 05:26.740 --> 05:27.660 advertisement of 107 05:27.660 --> 05:32.820 routes and the registration of subnets, handling both environments. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 107 05:27.660 --> 05:32.820 routes and the registration of subnets, handling both environments. 108 05:32.820 --> 05:38.500 Now we need to talk about the external border node. 109 05:38.500 --> 05:42.190 The external border node is also going to connect into the fabric, and we're 110 05:42.190 --> 05:42.620 going to 111 05:42.620 --> 05:49.050 have our VXLAN tunnels all established, but the external border node is going 112 05:49.050 --> 05:49.980 to connect 113 05:49.980 --> 05:52.020 to unknown subnets. 114 05:52.020 --> 05:55.580 Basically, it's intended to connect to the internet. 115 05:55.580 --> 05:59.950 Because we're connecting to the internet, we aren't going to be trying to 116 05:59.950 --> 06:00.660 advertise WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 116 05:59.950 --> 06:00.660 advertise 117 06:00.660 --> 06:02.300 any kind of subnets here. 118 06:02.300 --> 06:06.500 We're not registering anything whatsoever. 119 06:06.500 --> 06:10.770 That's a pretty fascinating part about this, because if I think about things 120 06:10.770 --> 06:11.940 from a traditional 121 06:11.940 --> 06:17.020 perspective, and I have a device that sits at my network edge that communicates 122 06:17.020 --> 06:17.500 to the 123 06:17.500 --> 06:19.820 internet, how do I get out to the internet? 124 06:19.820 --> 06:23.810 Well, I'm not asking that device to advertise internet routes and the full 125 06:23.810 --> 06:24.540 internet routing 126 06:24.540 --> 06:27.300 table into the network. 127 06:27.300 --> 06:30.460 Instead, it's going to advertise a default route. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 127 06:27.300 --> 06:30.460 Instead, it's going to advertise a default route. 128 06:30.460 --> 06:35.300 So if I have a specific network internally I need to go to, then I get 129 06:35.300 --> 06:36.580 forwarded to those 130 06:36.580 --> 06:38.060 internal networks. 131 06:38.060 --> 06:41.610 But if I am going out to the internet, well, the routers, the layer three 132 06:41.610 --> 06:42.540 devices, they 133 06:42.540 --> 06:45.700 have to check their routing tables, say, okay, do I know where that route is? 134 06:45.700 --> 06:49.770 And if I don't, well, that's when it's going to use the default route and get 135 06:49.770 --> 06:50.340 forwarded 136 06:50.340 --> 06:52.300 out to the internet. 137 06:52.300 --> 06:55.980 So that's the same concept here that we're going to use. 138 06:55.980 --> 06:59.970 The difference is it doesn't actually involve registering or advertising any 139 06:59.970 --> 07:00.820 kind of default WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 139 06:59.970 --> 07:00.820 kind of default 140 07:00.820 --> 07:01.980 route. 141 07:01.980 --> 07:07.960 So if I have a packet that's destined for the internet, well, how do I know 142 07:07.960 --> 07:08.780 what to do 143 07:08.780 --> 07:09.780 with this? 144 07:09.780 --> 07:14.690 If the control plane node doesn't know any routes that are attached to the 145 07:14.690 --> 07:16.260 external border 146 07:16.260 --> 07:19.020 node, well, here's what happens. 147 07:19.020 --> 07:27.120 We perform our map request and we get that negative map reply, which is a type 148 07:27.120 --> 07:28.100 of reply 149 07:28.100 --> 07:31.460 that says, I don't have an entry. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 149 07:28.100 --> 07:31.460 that says, I don't have an entry. 150 07:31.460 --> 07:37.730 As soon as I get this official response back that says there is no entry for 151 07:37.730 --> 07:39.460 your request, 152 07:39.460 --> 07:44.410 if well, that that implies that I need to follow the default route, so to speak 153 07:44.410 --> 07:44.980 , which 154 07:44.980 --> 07:48.780 is to go to the external border node. 155 07:48.780 --> 07:52.740 So this fabric edge node number one is going to take this packet in and it's 156 07:52.740 --> 07:53.860 going to forward 157 07:53.860 --> 07:58.650 it to its nearest external border node and allow the external border node to 158 07:58.650 --> 07:59.460 forward that 159 07:59.460 --> 08:00.900 packet on. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 159 07:59.460 --> 08:00.900 packet on. 160 08:00.900 --> 08:06.060 So very importantly, the external border node is doing no registration of 161 08:06.060 --> 08:07.220 routes into the 162 08:07.220 --> 08:11.220 fabric, whereas the internal border node is doing so. 163 08:11.220 --> 08:13.020 Now what about this last type? 164 08:13.020 --> 08:15.460 We're talking about this anywhere node. 165 08:15.460 --> 08:16.580 What is that about? 166 08:16.580 --> 08:22.100 Well, for smaller networks, we might find that the internet and all the 167 08:22.100 --> 08:23.740 external connections 168 08:23.740 --> 08:27.660 are all coming in through maybe one single node. 169 08:27.660 --> 08:29.980 And it might also not just be a matter of size. 170 08:29.980 --> 08:34.190 We might just find that there is no internal internet circuit with this WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 170 08:29.980 --> 08:34.190 We might just find that there is no internal internet circuit with this 171 08:34.190 --> 08:35.620 particular location. 172 08:35.620 --> 08:39.940 Instead, the internet is just another one of those connections that hangs off 173 08:39.940 --> 08:40.340 of the 174 08:40.340 --> 08:41.500 network core. 175 08:41.500 --> 08:45.860 Well, in this situation, this is no longer an internal border node. 176 08:45.860 --> 08:50.900 This would be an internal plus external or otherwise an anywhere border node. 177 08:50.900 --> 08:55.460 The anywhere border node simply performs both roles at the exact same time. 178 08:55.460 --> 08:59.220 And so it is going to register subnets that it learns internally. 179 08:59.220 --> 09:04.210 But also if we have a packet coming into a fabric edge node and we get this WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 179 08:59.220 --> 09:04.210 But also if we have a packet coming into a fabric edge node and we get this 180 09:04.210 --> 09:05.320 negative map 181 09:05.320 --> 09:09.580 reply saying the fabric isn't aware of where that subnet is, well, at that 182 09:09.580 --> 09:10.700 point, we would 183 09:10.700 --> 09:17.280 send it to the anywhere border node because it's our closest external border 184 09:17.280 --> 09:18.940 node function. 185 09:18.940 --> 09:22.830 It just happens to be on a border node that's also doing internal border node 186 09:22.830 --> 09:23.700 functionality 187 09:23.700 --> 09:24.900 as well. 188 09:24.900 --> 09:32.070 And so if our connection to the internet is and ultimately the default route is WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 188 09:24.900 --> 09:32.070 And so if our connection to the internet is and ultimately the default route is 189 09:32.070 --> 09:33.020 pointing 190 09:33.020 --> 09:37.970 in the same direction as the rest of the subnets that we're aware of, then we 191 09:37.970 --> 09:39.300 are going to 192 09:39.300 --> 09:41.340 refer to this as an anywhere node. 193 09:41.340 --> 09:46.070 However, if the internet is coming into a dedicated connection, then we will 194 09:46.070 --> 09:47.020 have distinct 195 09:47.020 --> 09:49.300 external and internal border nodes.