- [Instructor] Okay let's talk wireless channels real quick,
Wi-Fi networks that operate on the 2.4 gigahertz
and five gigahertz frequencies
use different ranges of channels.
And so let's talk about both of those
the 802.11n that runs on 2.4 gigahertz
and also g and b have three different ranges,
channels one through five,
six through 10 and 11.
And at least that's the United States channels.
It might go beyond that
in other countries for the COPT Exam,
you are interested in the United States channels
that are used.
The frequency ranges are listed here,
channel one is actually 2412 megahertz
or 2.412 gigahertz.
Channel two is 2417 megahertz and so on.
And it goes on that way through to channel 11
which is 2462 megahertz.
So your range is between 2412,
and it's really 2467 I believe,
or 66 total for the range you can use.
Now what's important here,
you wanna select the channel
first of all that doesn't conflict with other devices.
Other devices might be using
the same 2.4 gigahertz frequency,
but most importantly check wireless access points.
So let's say you already have a wireless network
running on channel one
and you need to install a second wireless network.
Well, you don't want that to be
within one through five
because those channels overlap,
and you'll get some interference.
So you wanna put that second wireless network
that second wireless access point
on either six through 10 or on 11.
If you have three access points,
put say one on the first one on channel one,
the second one on channel six,
and the third one on channel 11.
I like to use the later channel quite often,
like channel 11
or channel 10,
because most organizations will usually opt
for a lower number.
They'll opt for one or two or three.
So I'll go with a higher number to stay farther away
frequency wise and lower the interference altogether.
So that is the 2.4 gigahertz range,
but more and more
you're gonna be dealing with the five gigahertz ranges
especially with 802.11ac.
And so we have various ranges here,
We have 36, 40, 44, and 48,
which equate to frequency ranges
5180 through 5240 megahertz.
And then you have another whole group here:
52, 56 through 116,
then 132 through 144
and then 149 through 165.
Now there's a lot of gaps in here
and that's because there's military
and there's government applications using various
frequencies within five gigahertz.
And really most of the typical wireless access
points are only gonna give you this set of frequencies
and this set of frequencies.
One of the good things about five gigahertz
is all these frequencies run individually,
they don't overlap the way that say
channel one and channel two
on a 2.4 gigahertz wireless network would overlap.
You don't have to worry about that,
you could run one wireless access point
on 36 and one on 40 and one on 48.
But once again, as a tech,
I like to kind of go
with the later ones like 157, 161, 165
because chances are neighboring companies
and organizations will be using lower numbers.
And so I'll go with the higher numbers
to just to stay away as far as possible frequency wise
and reduce that possibility of interference.
So we'll take a quick look at our device here.
This is our wireless access point.
Here is the 2.4 network.
And you can see the channel used is 11.
You could set it to auto,
but generally again I'd recommend selecting a channel
and then you have to have all your wireless clients
connect on that channel.
And again, I like to use 11
but if you're on 2.4,
make sure it's you know
your first wireless access point will be
between one and five,
the second one between six and 10
and the third on 11.
And if you go beyond that many,
well then you have to start getting creative
or you could use five gigahertz networks if possible.
Now you also see channel width,
that's set to auto,
but you could increase that to 40 megahertz.
If you double the channel width,
you're gonna increase the entire wireless range.
So the overlap actually gets bigger.
So you have to watch out for that as well.
In that case,
you might want to just run one access point on the one
and the second access point on 11 if possible,
keep them as far apart as you can frequency wise.
On the five gigahertz portion of the wireless access point,
you see I'm using the last channel available,
at least in the US,
and that's 165.
And you'll see that we have options for 36, 40, 44, 48.
And that was that first range of channels.
And then 149 through 165,
that was that last range of channels that we showed.
And so we're using 165 for this,
the last one on the list,
again to keep it as far away from the typical organization
that's using the lower frequency,
like 36 or 40.
And so again,
keep in mind on the five gigahertz side,
this group and this group are gonna be the most common
for usage on 802.11ac networks,
but also n networks that operate in five gigahertz
and a networks that operate at five gigahertz.
So there's a little bit about wireless channels
make sure you know the three ranges
for 2.4 and understand that you can in the United States
at least you can use the five gigahertz channels starting
at 36 going all the way up to 165.
But again, the standards that you'll use are this group
36 through 48,
and this group 149 through 165,
and keep in mind there's gaps,
every four channels.
So you'd use 149, 153, 157, 161;
and then there's other gaps you know
between say 116 and 132,
you can't use any of those channels ever
because those are used by government, military applications,
that kind of thing.
And again the most common for SOHO Routers
and wireless access points is this group,
and this group as far as the channels go.