CWNP CWNA – WLAN Deployment

1. WLAN Deployment

This module is going to be about the wireless lan deployment. So we’re going to take a look at some of the common considerations that we should look at for the types of different wireless lan networks. And one of the big things we always have to ask in network engineering is what applications are we trying to support? So we’re going to talk about the different applications, the different devices, talk about data access, voice access, network extension to remote areas, which might include building to building connectivity through bridging. We’ll also look at the wireless isp and this thing they call Last mile delivery and how it can now be cheaper for us. We’ll even look at connecting your small office, home office, talking about mobile office networking and how to deal with the robos, the remote office and the branch offices.

2. Deployment Considerations for Commonly Supported WLAN Applications and Devices

So one of the first things that we always ask, as I just said, is that we want to look at what applications are being supported. Whenever you design a network, you have to remember business needs are first. So one of the big things with every network is data. Now, data has some resiliency. It doesn’t care how long and latency it takes for something to get from one point to the other as long as a transfer happens. And of course, some people might complain about the speed, but that’s a little bit different in trying to work that out compared to other types of applications like voice and video.

So when you have a data oriented applications, things like email, web browsing, getting the server farm, those that are most common, those are what come to people’s minds when they’re building wireless. And they forget that there are different types of traffic that need at least a faster not a speed or throughput, but a faster connection.

So when you’re planning for network traffic over any type of network, wireless or wired, you have to look at the protocols that are being implemented. Now, some protocols are those that are in common and open standards, and we use them everywhere. But some companies might develop their own applications that have their own protocols for communications, which is fine, because the switches and the routers, they care about things like your Mac address and the IP address.

They really don’t care what’s happening at layer four. It’s the two hosts that are talking to each other that really care about layer four. So you could have open standards or you could have some that were customized specifically for an application. I mean, as an example, back in the early ninety s I know that sounds like a lot of history. Unfortunately. I know some of you watching me are probably going to say, hey, I was born in the early 90s. Well, don’t tell me about that then. I’ll feel old. But back then, novell was the biggest one of the network operating systems.

And they had their own network address called spx or ipx. Excuse me? They had their own transport protocol called spx, but the devices didn’t care as long as they knew how to be able to forward the traffic. So like I said, they can be well designed, they can be based on documented standards, they can be proprietary. But we have to know what the applications are and what they’re using for the communications to be able to effectively build either a wireless or a wired network.

3. Real-Time Location Services Part1

Now, voice traffic is a little bit different, especially when we talk about voice over IP all the time. When you’re designing your wireless, even your wired networks, to support voice traffic, you have to remember that, unlike data, voice communications are not tolerant of network delays. They don’t support drop packets very well or sporadic connections. In other words, the sound quality of the voice voice will be bad if it takes more than 150 milliseconds to get from one phone to the other phone across your network, wireless or wired. If you drop packets, you’re dropping the quality of the sound, meaning that I’m not going to hear all the voice.

And by the way, these packets are not retransmitted, so once it’s dropped, it’s gone. If you drop too many, you’re going to have a problem with understanding the communications. So we’ve also have to consider how to design the wireless lan to support voice communication if you’re going to do voice communications over the wireless network. And that can be a challenge, because not only do we have to worry about latency or other things we call jitter, but we have to also worry about how the different vendors implement voice over IP in their products as they connect to our network.

4. Real-Time Location Services Part2

Now, video transmissions are a little bit different than voice. Usually video is going to be a streaming type of media, like going to companies like Netflix or hulu and watching the video. And if there’s a little pause or a little glitch, we can get over that. And by the way, video is much more complex than voice when they send voice traffic, at least like with cisco Networks, each packet is only 20 milliseconds of your voice. Video is a little different because depending on how much action there is in the video, the packets will be small or big. The more action, the bigger the packets. So they don’t have that fixed size, but at the same time, they’re also just doing screen refreshes with each frame that comes in. But anyway, in addition to the multiple streams of data for video and voice, video often has streams for setting up and tearing down the connection. So unless you’re going to use the wireless network for a realtime video conference, that would be like a realtime phone call, then video can usually take a backseat to the importance we place on audio.

5. Real-Time Location Services Part3

Now, most manufacturers of your wireless lan, wireless lan controllers, have some sort of location capability with their products. And what that means is that we have something like this map that shows us where we place the access points. And I don’t quite see where all the access points are, but let’s say we have one here, one here, one here. So what happens is that if if we actually wanted to locate somebody, imagine, if you would, somebody lost their cell phone, lost their tablet in the office. They don’t remember where they put it, but it’s still on and it’s still connected through triangulation. With these access points, we can come in close to a few feet about where that object is. Or if you’re tracking a person and you like to stalk those people, you could watch them as they’re walking down the hallway and moving to other parts of the building. But either way, that location capability is kind of cool. As I said, it really works well. And trust me, there are people who forget where they leave things. It really works well in trying to find out where those different devices are.

6. Mobile Devices

So mobile devices seem to be the primary thing that people are using now for their entire life, whether it’s their phone, their smartphone or their tablet. And when they come to work, they expect that they want to be able to connect to your wifi network, to be able to use your network services instead of their cellular capability, which is fine. And so we now have to deal with what we’ll talk about much later called BYOD or bringing your own device.

But almost all of them have the ability to connect to an 800 and 211 radio. Now, there are some concerns that we should think about when you integrate those devices into the network. Number one is to make sure that the devices are actually capable of connecting to the network using the right kinds of authentication. authentication security should not change just because somebody is using their phone instead of their workstation. The security is about the data in your network. So we want to make sure that that device is capable of using the encryption protocols that we want to use along with them to be able to smoothly roam throughout the network.

And originally when we were designing these wireless networks, we never thought about roaming. I mean, if you go back historically we had a bunch of basic service sets where we’d put in the access point, give it full power, try to cover as much area as we could and we didn’t think about somebody roaming. We’re going to address those issues a little bit later as we go through this module. But anyway, that’s something else we now have to worry about.

So we have to not only provide the network access and do that based hopefully on the identity of the user or of the device, or both, but also we have to look at the type of device or other devices and what their characteristics are for connections. And I say that because we have some high end encryption that we like to use for the regular workstation, the regular laptop. But most of your smart devices don’t have as much processing power to support some of those different types of encryption. So we have to make sure we understand what those characteristics are and whether or not it’s suitable to support that in your network.

7. Corporate Data Access and End-User Mobility

Now, we have seen an increase in throughput from the early days when we look at technologies like Eight or 211 N, or eight or 211 C or AC. Excuse me. And many companies have been transitioning to these higher speeds networks and also at the same time reducing the number of devices that are connecting to the network through a wired connection. I mean, if you think about it, on average it might cost you you $200 or more just to supply a wired connection in an office where with wireless, after you buy the actual access point, there’s no extra cost to you for somebody to be able to connect to your network. So it really is cheaper. And so that’s why we’re seeing fewer and fewer wired networks now. The other thing we have to do is be able to provide continuous access and availability. And the other benefit is we can do it now throughout the facility, which is something that has become almost a must in wireless networks in these past few years.