WEBVTT

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 Hello and welcome to this video, which
 I'm going to give you a demonstration

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 of RF channel implementations.

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 That is our topic for this video.

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 So whether you're working on a Mac or
 a tablet or a Windows laptop, there's

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 a variety of tools that you can download,
 software tools to actually give

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 you visibility into the RF environment
 around you, tools in which you

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 can see how many access points are advertising,
 what the names or SSIDs

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 are, those access points are advertising,
 and you can even see what channels

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 are advertising in the width or size
 of those access point channels.

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 Let's start. So I'm doing this
 demonstration on a Mac.

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 So let me just show you some of the
 common tools available to you in a

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 Mac, and then you can find something similar
 if you're in a Windows environment.

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 So I'm going to minimize
 this for a second.

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 So within a Mac, if you click up here
 in the upper right corner that's

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 at the Wi-Fi symbol, and there it is,
 so the thing that looks like radio

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 frequency is spreading out there, if
 you just click on that once, if you

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 left click on it, you will see a listing
 of all the BSSs that are being

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 advertised to you, and you'll see the
 names of them, the SSIDs, like cable

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 Wi-Fi and rego private,
 so on and so forth.

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 Now keep in mind that the only time you're
 going to see something in this

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 list is if an access point has been intentionally
 configured to advertise

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 or what's called broadcast,
 its SSID.

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 Sometimes, as like a crude form of
 security, someone will configure an

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 SSID and then they'll deselect the box
 saying, do not advertise it, which

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 means that that access point is sending
 out its special messages saying,

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 hey, here I am, here I am.

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 I've got a BSS you could use,
 but it's hiding the name.

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 And so it does not show up here.

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 So in that type of environment, if you
 knew what that name was in advance,

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 you could go into your Wi-Fi settings,
 type in that name, say this is

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 what I want to connect to, and then
 you could connect to that SSID, even

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 though it would not show
 up in this list.

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 So whether you're on a Mac or a ThinkPad
 or a Tabo or whatever, just because

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 you see a listing of SSIDs doesn't
 mean that's all that's available.

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 There could very well be some that
 you're not seeing because the SSID

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 name has been hidden.

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 Now, furthermore, here's an example
 of a tool that you can download for

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 free, which is called
 Wi-Fi Explorer Lite.

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 Now this is on a Mac, I'm sure they
 have something similar in a Windows

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 or tablet version, but this tool does
 exactly what your laptop's doing.

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 It's scanning, it's actually using the
 same knit card that's built into

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 your laptop or tablet or notebook.


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 And it's actually graphically displaying
 to you all those same Wi-Fi networks,

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 but you're getting a
 lot more information.

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 So for example, if I sort here on channel
 width, we can see a lot of Wi

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-Fi networks in the 2.4 gigahertz space
 are being advertised as your basic

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 20 megahertz channel.

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 And if you click on each
 one, it highlights it.

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 So for example, look at this one here,
 it actually says hidden network.

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 This is one that did not show up in
 my drop down list for just a second,

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 because it's SSID is hidden.

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 And yet this is picking it
 up right here in this tool.

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 So we can see this is a
 20 megahertz network.

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 It's operating across
 channel seven.

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 So we can see right here, channel seven
 is right in the midpoint of this.

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 And so this is 20 megahertz wide.

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 We can go up a little bit further.


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 Oh, do we have any 40
 megahertz networks?

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 And we can see, yes, there are.

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 So for example, here is
 another hidden network.

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 Notice it's much wider
 now twice as wide.

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 That's a 40 megahertz network operating
 on channel number one.

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 There's actually a couple of them
 operating on channel number one.

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 So for example, look at these two networks
 here that are called pirates.

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 Both of them are 40
 megahertz wide.

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 One is operating on channel one.

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 One is operating on channel two.

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 That is a lot of overlap
 between those networks.

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 So there is, if you were actually connected
 to either one of those, if

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 those access points are really close
 together and you've got a lot of

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 clients associated to both access points,
 there is a significant risk

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 of interference between
 those two networks.

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 We have several here that
 are 40 megahertz wide.

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 And now we're going up into the UNII
 space, the five gigahertz range.

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 And we can see there are 40
 megahertz networks up there.

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 And we can even see some
 80 megahertz networks.

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 No 80 megahertz in the 2.4 space.

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 There's just not enough
 room for that.

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 But we can see several of them
 in this space right here.

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 And when 802.11aX comes out, you might
 even start seeing some 160 megahertz

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 wide networks, which will consume
 a significant amount of bandwidth.

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 Also, you can notice here, notice the
 names of some of these networks,

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 how they're, I should say
 the generation, Y54, Y55.

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 So these are names that the Wi-Fi
 Alliance has appended to networks.

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 So currently the last
 generation is Y55.

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 That's the same as 802.11ac.

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 Notice how it says AC here?

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 So whenever you see something, it's 802
.11ac, the Wi-Fi Alliance has called

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 that Wi-Fi 5. If we go down to Wi-Fi
 4, that means that it's only doing

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 a maximum of 802.11n, which
 came out in 2009.

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 Probably not going to say anything
 much less than that between 4 or 5.

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 When 802.11aX comes out, that'll show
 up in a tool like this as Wi-Fi

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 6. That's what that will show.

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 So I just want to demonstrate this tool
 as an example of many tools you

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 can download to get really good visibility
 into what Wi-Fi networks are

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 around you, their relative strength or
 power, and how much bandwidth each

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 Wi-Fi network is using.

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 So that concludes this video.

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 I hope you found it useful
 and thank you for watching.