WEBVTT 00:00:00.000 --> 00:00:18.959 Alright everyone, welcome to the fourth installment of our Encore wireless exam focus dive into 00:00:18.959 --> 00:00:21.879 all that is wireless in the Encore world. 00:00:21.879 --> 00:00:29.160 So now we're going to talk about the AP discovery and join process. 00:00:29.160 --> 00:00:31.559 Now there's been a lot that we've talked about. 00:00:31.559 --> 00:00:37.880 We've talked about frequencies, we've talked about antenna types, we talked about AP placement, 00:00:37.880 --> 00:00:40.000 and we're kind of going quickly through that. 00:00:40.000 --> 00:00:43.799 That's because this is focused on what you need to know for the exam. 00:00:43.799 --> 00:00:49.160 I do suggest that you guys, when you have time, take a wireless course to better understand 00:00:49.160 --> 00:00:52.919 some of the principles behind this and maybe some of the background information that we're 00:00:52.919 --> 00:00:57.439 kind of steamrolling over just to get you the information you need. 00:00:57.439 --> 00:01:02.480 So let's talk about the AP discovery and join process really quickly. 00:01:02.480 --> 00:01:08.120 Now when we're talking about this process, what you have to remember is when we are looking 00:01:08.120 --> 00:01:18.440 at the Cisco product, it's really meant to be an AP, let me roll back here, an AP and 00:01:18.440 --> 00:01:20.199 a wireless LAN controller. 00:01:20.199 --> 00:01:26.559 And really this is what's called a lightweight access AP or LWAP or one of the billions of 00:01:26.680 --> 00:01:35.199 acronyms we use in this industry, but a lightweight access point and a wireless LAN controller. 00:01:35.199 --> 00:01:40.559 Now what happens with a lightweight access point is it doesn't have everything it needs 00:01:40.559 --> 00:01:42.839 to run a wireless network. 00:01:42.839 --> 00:01:48.959 It relies on a manager or a controller and that is the wireless LAN controller. 00:01:48.959 --> 00:01:54.839 And we create what's called a CAPWAP tunnel that goes from a lightweight access point 00:01:54.839 --> 00:01:56.879 to a wireless LAN controller. 00:01:56.879 --> 00:02:00.599 And all the traffic in there is contained in this tunnel. 00:02:00.599 --> 00:02:08.960 Now this tunnel may traverse a switch, it may traverse a router, but you really don't 00:02:08.960 --> 00:02:09.960 see that. 00:02:09.960 --> 00:02:12.479 The traffic doesn't really have a way to escape. 00:02:12.479 --> 00:02:17.360 It is directly taken to the wireless LAN controller. 00:02:17.360 --> 00:02:23.679 You can study more on that later, but that's kind of outside the scope of our Encore course. 00:02:23.679 --> 00:02:26.639 Let's talk about this process specifically. 00:02:26.639 --> 00:02:34.039 So an AP sends a CAPWAP discovery request to a wireless LAN controller, basically asking, 00:02:34.039 --> 00:02:37.479 is there any wireless LAN controllers I can talk to? 00:02:37.479 --> 00:02:43.440 And what happens is any wireless LAN controller it can reach will respond, yeah, I'm here, 00:02:43.440 --> 00:02:44.520 go ahead. 00:02:44.520 --> 00:02:49.880 And in some environments that may be one, it may be two, it may be three, it may be 00:02:49.880 --> 00:02:50.880 four. 00:02:51.240 --> 00:02:58.639 It just depends on your environment and how far the lightweight access point can reach. 00:02:58.639 --> 00:03:04.639 So all the wireless LAN controllers respond that receive the discovery request. 00:03:04.639 --> 00:03:06.880 It's important you understand that. 00:03:06.880 --> 00:03:10.000 It sends the response that, hey, I'm here. 00:03:10.000 --> 00:03:16.360 Now the wireless LAN controller does not choose whether or not the AP joins. 00:03:16.360 --> 00:03:22.279 It's not the one that's going to decide which wireless LAN controller takes on this access 00:03:22.279 --> 00:03:23.279 point. 00:03:23.279 --> 00:03:29.600 It's the access point itself that chooses the wireless LAN controller it wants to join. 00:03:29.600 --> 00:03:34.600 Now a wireless LAN controller can deny that request based on traffic, or maybe it's already 00:03:34.600 --> 00:03:39.360 overloaded, or maybe there's something happening that it's not doing well and it just doesn't 00:03:39.360 --> 00:03:40.919 want the traffic. 00:03:40.919 --> 00:03:46.800 So the AP chooses who they want, then the wireless LAN controller sends the join response, 00:03:46.800 --> 00:03:52.199 okay, fine, I will manage your AP. 00:03:52.199 --> 00:03:58.880 This is important to understand that we are using CAPWAP, LWAP is old or legacy, but we 00:03:58.880 --> 00:04:03.440 are using the CAPWAP protocol and that's why we call them CAPWAP tunnels. 00:04:03.440 --> 00:04:07.559 These are the control and provision of wireless access points. 00:04:07.559 --> 00:04:11.679 That's what we're doing with that protocol. 00:04:11.679 --> 00:04:16.160 Now the discovery phase is more than just a broadcast, that's the first try. 00:04:16.160 --> 00:04:21.440 I'm going to try and broadcast a message on a local network and see if any wireless LAN 00:04:21.440 --> 00:04:22.440 controller responds. 00:04:22.440 --> 00:04:27.160 It can also check previously joined wireless LAN controllers. 00:04:27.160 --> 00:04:33.119 Let's say I have an AP and for some reason I remove the AP and add it later. 00:04:33.119 --> 00:04:40.519 By adding it later, back to the network, what I'm saying is, oh, I'm back. 00:04:40.519 --> 00:04:46.679 And what the AP is going to do is it's going to look at its list of older wireless LAN 00:04:46.679 --> 00:04:50.640 controllers it's joined previously and it's going to attempt to join them. 00:04:50.640 --> 00:04:55.720 And it can keep up to a list of eight and that just depends on the model you're using. 00:04:55.720 --> 00:05:01.079 Next up, we can also use DHCP option 43. 00:05:01.079 --> 00:05:07.880 Now many of you know DHCP as the way we hand out IP addresses, the default gateway, subnet 00:05:07.880 --> 00:05:11.559 masks, that kind of networking information. 00:05:11.559 --> 00:05:20.200 Option 43 is additional vendor information, additional vendor. 00:05:20.200 --> 00:05:24.920 That means I can put additional information in there, extra information. 00:05:24.920 --> 00:05:33.559 In this case, I can put my wireless LAN controller location, its vendor, who it is, what it's 00:05:33.559 --> 00:05:40.200 trying to do, like you can actually add in information so that when that AP boots up 00:05:40.200 --> 00:05:46.480 on the network and pulls DHCP, boom, it already has the information for the wireless LAN controller 00:05:46.480 --> 00:05:49.799 or controllers on the network. 00:05:49.799 --> 00:05:52.480 I can also set up a DNS record. 00:05:52.480 --> 00:06:02.799 Now, this DNS record has to be mapped so that here, this ciscocapwapcontroller.localdomain 00:06:02.799 --> 00:06:07.040 is mapped to the wireless LAN controller IP address. 00:06:07.040 --> 00:06:08.279 Know this, please. 00:06:08.279 --> 00:06:11.760 Know this DNS record. 00:06:11.760 --> 00:06:13.480 Know that. 00:06:13.480 --> 00:06:14.519 Yeah, I said it. 00:06:14.519 --> 00:06:16.359 You should probably know that. 00:06:16.359 --> 00:06:20.279 And then lastly, we have the AP configuration manually. 00:06:21.160 --> 00:06:23.320 Usually, you can use an Ethernet. 00:06:23.320 --> 00:06:29.720 If your AP has it, you can use an Ethernet cord or a rollover cord, depending on the model, or even a USB, 00:06:29.720 --> 00:06:38.359 depending, again, on the model, to log in directly to the AP and manually configure through GUI or CLI, 00:06:38.359 --> 00:06:40.559 again, depending on the model. 00:06:40.559 --> 00:06:47.600 You can actually enter this information in so it can contact the wireless LAN controller directly. 00:06:47.600 --> 00:06:52.239 Now, we are going to dive very deep into this. 00:06:52.239 --> 00:06:59.679 And we're going to dive very deep into it, not because you're going to have to do this in the real world, 00:06:59.679 --> 00:07:05.440 but because it's something you might need to understand if you were going to take the exam. 00:07:05.440 --> 00:07:08.600 Okay, I'm going to take myself off the screen. 00:07:08.600 --> 00:07:11.440 Warning, this is a little complicated. 00:07:11.440 --> 00:07:15.600 This is something that I personally would never do without a calculator, 00:07:15.600 --> 00:07:23.839 but this is something that I want you to be able to do if you were using a dry erase marker and a dry erase board. 00:07:23.839 --> 00:07:28.119 Okay, so let's talk about actually configuring option 43. 00:07:28.119 --> 00:07:33.440 Here, this is a Windows Server implementation of DHCP. 00:07:33.440 --> 00:07:36.760 And you can see here, we have our available options. 00:07:36.760 --> 00:07:40.320 We're going with option 43, vendor-specific info. 00:07:40.320 --> 00:07:41.559 That's checked. 00:07:41.559 --> 00:07:47.040 And you can see here where it says under binary, we have this hexadecimal value. 00:07:47.040 --> 00:07:50.480 Believe it or not, this hexadecimal value tells me things. 00:07:50.480 --> 00:07:57.920 I can see right now that we're dealing with a Cisco wireless LAN controller. 00:07:57.920 --> 00:08:05.959 I can see that I'm dealing with a specific one IP address, so one wireless LAN controller. 00:08:05.959 --> 00:08:13.799 And here, believe it or not, I can see the actual IP address there. 00:08:13.799 --> 00:08:21.440 Yeah, so let's dive into how I know these things and how you can get to know these things as well. 00:08:21.440 --> 00:08:26.839 So figuring out this value, the TLV value. 00:08:26.839 --> 00:08:30.399 Okay, F1 is always. 00:08:30.399 --> 00:08:34.479 This means Cisco wireless LAN controller. 00:08:34.479 --> 00:08:38.919 So F1 is what we're always going to see right here at the beginning. 00:08:38.919 --> 00:08:40.599 That part's easy. 00:08:40.599 --> 00:08:44.559 Now, the number of wireless LAN controllers, how did I know that? 00:08:44.559 --> 00:08:48.679 Well, this type value, this is pretty easy. 00:08:48.679 --> 00:08:52.840 The number of controllers times four. 00:08:52.840 --> 00:09:00.559 So if I have one controller times four, the value here is going to be 04. 00:09:00.559 --> 00:09:02.960 We're talking about hexadecimal. 00:09:02.960 --> 00:09:12.599 If my value of two IPV would be eight, we would be looking at a value of what? 00:09:12.599 --> 00:09:18.359 If I have two wireless LAN controllers, we multiply that by four, we get a value of eight. 00:09:18.359 --> 00:09:22.640 This would then be eight. 00:09:22.640 --> 00:09:28.880 Okay, so the number of wireless LAN controllers multiplied by four. 00:09:28.880 --> 00:09:31.159 Next up is the hard one. 00:09:31.159 --> 00:09:40.719 We have to do a translation from an IP address into binary and then from binary into hexadecimal. 00:09:40.719 --> 00:09:42.520 I'm very sorry. 00:09:42.520 --> 00:09:47.119 If I was doing this in the real world, I would 100% use a calculator. 00:09:47.119 --> 00:09:53.080 And I would 100% tell any junior administrator who asked me to use a calculator. 00:09:53.080 --> 00:09:57.320 But for this exam, I want you to know how to do this, okay? 00:09:57.400 --> 00:10:01.320 So you go ahead and convert 172 into binary. 00:10:01.320 --> 00:10:08.359 If you do not remember how to do this, it's time to do some brushing up. 00:10:08.359 --> 00:10:12.640 If you do the math, we're going to take 172 and dot a decimal. 00:10:12.640 --> 00:10:18.359 That's the first octet right here of the IP address of the wireless LAN controller. 00:10:18.359 --> 00:10:25.479 And then we're going to turn that into binary, 10101100. 00:10:25.599 --> 00:10:27.080 Hmm, okay. 00:10:27.080 --> 00:10:28.599 That makes sense. 00:10:28.599 --> 00:10:30.960 Remember your place values. 00:10:30.960 --> 00:10:32.159 What is that value? 00:10:32.159 --> 00:10:36.679 That's 01, that's 20. 00:10:36.679 --> 00:10:37.640 What's that? 00:10:37.640 --> 00:10:43.520 40, remember we're doing our values here. 00:10:43.520 --> 00:10:53.440 So, now we need to break it out into nibbles or four bits. 00:10:53.440 --> 00:11:01.919 So we take the 1010 and we break that from the 1100. 00:11:01.919 --> 00:11:05.000 All right, we've broken that apart. 00:11:05.000 --> 00:11:10.679 Now we can convert this back into a hexadecimal number. 00:11:10.679 --> 00:11:15.760 All right, so if we take the 1010, what's the value here? 00:11:15.760 --> 00:11:21.039 Well, if this is 1 and that's 2 and that's 4 and that's 8, 00:11:21.039 --> 00:11:24.479 if we add the 2 bit and the 8 bit, we get how much? 00:11:24.479 --> 00:11:25.880 What's our value? 00:11:25.880 --> 00:11:27.760 Our value is 10. 00:11:27.760 --> 00:11:31.919 Well, 0 through 9, hexadecimal, what comes after 9? 00:11:31.919 --> 00:11:37.760 10, 10 is represented as A. There we go, A. 00:11:37.760 --> 00:11:39.960 Let's take our values again. 00:11:39.960 --> 00:11:44.640 This is 1, this is 2, this is 4, this is 8. 00:11:45.400 --> 00:11:52.320 Remember, our binary dotted decimal places, their value, 00:11:52.320 --> 00:11:55.159 the 1 bit is set to 0, so that's 0. 00:11:55.159 --> 00:11:58.359 The 2 bit is set to 0, so it's 8 plus 4 here. 00:11:58.359 --> 00:11:59.520 Those are the values I have. 00:11:59.520 --> 00:12:01.119 What's 8 plus 4? 00:12:01.119 --> 00:12:02.640 12. 00:12:02.640 --> 00:12:07.400 Well, we know A is 10, B is 11, C is 12. 00:12:07.400 --> 00:12:12.919 All right, so we know it's C. So 1010 00:12:12.919 --> 00:12:16.239 is A1100C. 00:12:16.239 --> 00:12:18.799 All I do is I keep going through those numbers 00:12:18.799 --> 00:12:22.400 and I plug it in here. 00:12:22.400 --> 00:12:28.320 Notice the A gets plugged in right there. 00:12:28.320 --> 00:12:31.080 The C gets plugged in right there. 00:12:31.080 --> 00:12:33.520 And as I continue through this calculation, 00:12:33.520 --> 00:12:35.039 I keep adding numbers. 00:12:35.039 --> 00:12:37.919 Now, luckily, if I was going to test you on this, 00:12:37.919 --> 00:12:40.559 I wouldn't test you past here. 00:12:40.559 --> 00:12:43.320 So you don't have to do this a ton. 00:12:43.320 --> 00:12:46.320 But be aware of how to do it. 00:12:46.320 --> 00:12:47.840 It's really important. 00:12:47.840 --> 00:12:50.400 Know your place values in binary. 00:12:50.400 --> 00:12:54.280 Know how to do a conversion from binary into hex, 00:12:54.280 --> 00:12:57.080 from dotted decimal into binary. 00:12:57.080 --> 00:13:01.320 And know that F1 is always what we start with. 00:13:01.320 --> 00:13:05.039 And then we multiply the number of controllers by 4 00:13:05.039 --> 00:13:06.840 to get this value here. 00:13:11.559 --> 00:13:12.559 I know. 00:13:12.559 --> 00:13:13.840 It's a pretty tough one. 00:13:13.840 --> 00:13:17.080 But I believe you guys will do OK. 00:13:17.080 --> 00:13:20.320 If you need to, study that more than once. 00:13:20.320 --> 00:13:22.919 Go through that portion more than once. 00:13:22.919 --> 00:13:25.280 Next, let's talk about discovery outside 00:13:25.280 --> 00:13:26.359 of a local area network. 00:13:26.359 --> 00:13:28.640 I'm going to have to take myself off the slides again. 00:13:28.640 --> 00:13:30.320 I'm right in the middle of it. 00:13:30.320 --> 00:13:32.719 So let's say if I have a local area network, 00:13:32.719 --> 00:13:35.559 but my wireless LAN controller is outside of that, 00:13:35.559 --> 00:13:38.280 I'm going to need to configure an IP helper address. 00:13:38.280 --> 00:13:40.880 Many of you have done this already or have done this. 00:13:40.880 --> 00:13:43.919 If you haven't, this is the configuration below. 00:13:43.919 --> 00:13:47.080 You can see I have a distribution switch. 00:13:47.080 --> 00:13:49.440 This is a layer 3 switch. 00:13:49.440 --> 00:13:53.119 I have config, interface, VLAN, then the number, 00:13:53.119 --> 00:13:57.320 let's say 100 in this case, and then IP helper address 00:13:57.320 --> 00:13:59.200 and where I'm going. 00:13:59.200 --> 00:14:00.400 That's all. 00:14:00.400 --> 00:14:03.799 This is very similar to a DHCP relay agent 00:14:03.799 --> 00:14:04.799 that you might set up. 00:14:04.799 --> 00:14:07.479 But this time, we're just using it as a helper address. 00:14:07.479 --> 00:14:10.679 What we're telling this lightweight access protocol to do 00:14:10.679 --> 00:14:14.679 is, hey, I know you're in this VLAN right here, 00:14:14.679 --> 00:14:17.359 but if you need to get to this wireless LAN controller, 00:14:17.359 --> 00:14:19.159 we're going to actually help you 00:14:19.159 --> 00:14:21.799 and push you out into the right space. 00:14:21.799 --> 00:14:23.760 That's what this configuration does. 00:14:25.400 --> 00:14:27.119 All right, just make sure you understand 00:14:27.119 --> 00:14:28.719 how that configuration works. 00:14:28.719 --> 00:14:33.400 Interface, VLAN, the VLAN number, IP helper address, 00:14:33.400 --> 00:14:35.520 and then the IP address where we're going. 00:14:37.880 --> 00:14:39.640 Again, this is the join phase. 00:14:39.640 --> 00:14:42.960 We use the encrypted between AP manager and AP. 00:14:42.960 --> 00:14:44.719 It's wireless LAN controller. 00:14:44.719 --> 00:14:47.760 AP decisions process priority. 00:14:47.760 --> 00:14:51.280 This is the priority for that join phase. 00:14:51.280 --> 00:14:53.640 Wireless LAN controller, it's used in the past. 00:14:53.640 --> 00:14:56.520 So the history, it's going to rely on that first. 00:14:56.520 --> 00:14:59.200 It's going to look at the primary controller, 00:14:59.200 --> 00:15:02.440 and then it's going to choose the wireless LAN controller 00:15:02.440 --> 00:15:04.039 with the lowest number of APs. 00:15:04.039 --> 00:15:06.280 This is the AP's decision process. 00:15:06.320 --> 00:15:08.559 Remember, if I rolled all the way back, 00:15:08.559 --> 00:15:10.039 if I kept rolling the slides back, 00:15:10.039 --> 00:15:11.760 remember that process where I said, 00:15:11.760 --> 00:15:15.440 the AP decides what wireless LAN controller to join? 00:15:15.440 --> 00:15:16.280 This is that. 00:15:16.280 --> 00:15:18.880 This is what it uses to make that decision. 00:15:18.880 --> 00:15:21.359 It goes with its history, what it's joined before, 00:15:21.359 --> 00:15:23.400 what it knows works. 00:15:23.400 --> 00:15:26.400 Then it goes to who's the primary controller, 00:15:26.400 --> 00:15:28.000 and then if it doesn't know that, 00:15:28.000 --> 00:15:29.640 then it goes with the wireless LAN controller 00:15:29.640 --> 00:15:31.799 with the lowest number of APs. 00:15:31.799 --> 00:15:34.119 That does not necessarily mean 00:15:34.119 --> 00:15:35.799 that the wireless LAN controller 00:15:35.799 --> 00:15:38.440 is absolutely going to accept the AP, 00:15:38.440 --> 00:15:40.559 but that's who the AP is going to choose 00:15:40.559 --> 00:15:43.200 and is going to send that join request to. 00:15:45.960 --> 00:15:49.760 So what happens after we're completely done with all that? 00:15:49.760 --> 00:15:52.479 Let me throw myself back on screen here real quick. 00:15:52.479 --> 00:15:54.080 Well, when we're done with all that, 00:15:54.080 --> 00:15:57.119 there needs to be a few things to wrap things up. 00:15:57.119 --> 00:15:59.840 We have to make sure that the image, 00:15:59.840 --> 00:16:03.840 the iOS, the operating system of the AP 00:16:04.520 --> 00:16:07.599 matches the wireless LAN controller in compatibility. 00:16:07.599 --> 00:16:11.320 And if not, you're going to have to look for updates. 00:16:11.320 --> 00:16:12.960 We're going to have to do a configuration check 00:16:12.960 --> 00:16:16.719 to make sure that that AP has an OS 00:16:16.719 --> 00:16:19.000 that can work with that wireless LAN controller. 00:16:19.000 --> 00:16:21.679 Otherwise, you got to start over, right? 00:16:21.679 --> 00:16:22.760 It makes sense. 00:16:22.760 --> 00:16:24.119 It needs to be compatible. 00:16:25.200 --> 00:16:27.200 Configuration check, do you need to do updates? 00:16:27.200 --> 00:16:29.440 And in this day and age, 00:16:29.440 --> 00:16:33.559 you absolutely, if you're bringing an older wireless AP, 00:16:34.239 --> 00:16:36.320 any AP on your network, make sure it's up to date, 00:16:36.320 --> 00:16:38.760 especially with all the security patches 00:16:38.760 --> 00:16:40.640 and everything else that's going on, 00:16:40.640 --> 00:16:42.239 make sure you're fully up to date. 00:16:42.239 --> 00:16:44.960 And then last but not least, register your device. 00:16:46.320 --> 00:16:49.440 I don't know how many environments have I been in in my life 00:16:49.440 --> 00:16:51.359 where people just don't register things. 00:16:51.359 --> 00:16:52.599 Register your device. 00:16:52.599 --> 00:16:54.320 It gives you warranty access. 00:16:54.320 --> 00:16:57.239 It allows you to call up tax support. 00:16:57.239 --> 00:16:59.599 It's an important step in the process. 00:16:59.599 --> 00:17:02.599 So that was our discovery and join process. 00:17:02.599 --> 00:17:05.880 I know there was some difficult stuff in there. 00:17:05.880 --> 00:17:09.000 Please review that until you get an understanding 00:17:09.000 --> 00:17:10.040 of how that works. 00:17:10.880 --> 00:17:12.280 It's a difficult process, 00:17:12.280 --> 00:17:16.199 but very important to not only your Cisco certification path 00:17:16.199 --> 00:17:18.040 but just understanding in general how it works 00:17:18.040 --> 00:17:21.199 and maybe it's a cool party trick. 00:17:21.199 --> 00:17:22.479 I'm not sure. 00:17:22.479 --> 00:17:25.359 Anyways, thanks for watching. 00:17:25.359 --> 00:17:27.319 I'll see you in the next video. 00:17:27.319 --> 00:17:28.160 Bye for now.