Instructor: In this lesson,
we're going to talk about the different types
of networking hardware that's used to transmit data
from one place to another and from one device to another.
Whether that's carrying voice, video, or data,
all of this stuff needs to go across the network
so it can do its intended function.
So what comprises the network?
Well, network components can be things
like network interface cards, hubs,
unmanaged and managed switches, wireless access points,
routers, firewalls, patch panels,
Power over Ethernet devices, cable modems,
digital subscriber line modems, optical network terminals,
and software defined networks.
Now, some of these terms may probably look familiar,
but others may not.
So we're going to go briefly through each of these
as we go through this lesson.
First, we have NICs or network interface cards.
Now, most computers have a network interface card
that provides an ethernet connection to your network.
This can be integrated into your motherboard,
added as an expansion card,
or added as an external peripheral using a USB connection.
This network interface card is then going to be used
to connect the computer to the network.
And it can be wired using a copper NIC
that relies on a Cat 5 or above cabling.
Or you might have a wired fiber NIC.
And this relies on a fiber optic cable.
Or you might use a wireless NIC.
And this connects to a wireless access point
using radio frequency waves in the Wi-Fi ranges
of 2.4 gigahertz to 5 gigahertz.
Next, we have a hub.
Now, a hub is an older piece of networking technology,
but you may still come across it in the field.
Now, a hub has a number of different ports,
generally between 4 and 48 ports.
And this allows up to 48 computers
to all be connected to this hub.
Each computer is connected to a single port on the hub.
Now, the way a hub works is
it's going to be using a wired interface.
Most commonly, it's going to be a wired copper connection
relying on RJ45 connectors in each of those ports.
This can operate either at 10 megabits per second
or as fast as 100 megabits per second,
but typically, not any faster than that.
When you're dealing with a hub,
all of the computers that are attached to that hub
are going to be considered part of its collision domain.
This is because hubs operate
in what is known as broadcast mode.
I like to think about hubs as if I was sitting
in a classroom with 30 students.
If I was the hub,
and all of you were sitting in the class with me
and you wanted to ask a question,
you couldn't all do it at the same time
because I'm only one person,
and I can only hear one person talking at a time.
So with a hub, if two people talk at the same time,
we would have a collision.
Now, in the classroom environment,
I can control that collision by telling everybody
that they can't talk unless they raise their hand first.
And this would be a very controlled way
for us to be able to have our class
so nobody's talking over each other.
But hubs don't have that capability.
So instead, all of our network client devices,
if they detected a collision has occurred,
will stop talking.
They'll pick a random time to count up to,
and then, they'll try retransmitting again.
So going back to my classroom example,
if Mary and Joe both tried to talk at the same time,
they would stop.
One would pick a number, maybe three seconds.
And the other one would pick another number,
maybe two seconds.
And after their time relapsed, in this case, two seconds,
they would start speaking.
And that way there wouldn't be another collision
because the second person who was waiting three seconds
would hear that there's already somebody talking
and they wouldn't talk again until that person finishes.
So that's how a hub works in theory.
Now, the problem with this is
that this slows down the entire network connection,
because if I have four people on a hub,
that's only four people who are talking
at the same time for possible collisions.
But as I move to those larger hubs with 48 people,
that means there are a lot of collisions
happening all of the time.
Now, that's just one problem with the hub.
The second problem is that everybody can hear everything
that's being said because we're all in the same classroom,
or in this case, we're all in the same hub.
Whenever somebody sends something to the hub,
it's going to re-broadcast that out every port that it has.
And then, it's going to say, "I have a message for Jason."
And anybody who's not Jason is going to
basically cover their ears and pretend to not hear it.
But all these devices could,
if they wanted to, listen to that.
And the way these network clients know
who is being targeted to be spoken to
is by using what's known as a MAC address,
which is its own address on the local area network.
So Jason's computer has a MAC address.
And so does Joe's.
And so does Mary's.
And by having that, when the hub sends out a message,
it says, "This message is meant for Jason."
Everybody else will ignore it in theory
because they're not Jason.
So we now have two basic problems with hubs.
One is these collisions.
And the second is that people could uncover their ears
and listen to traffic that's not meant for them.
To overcome both of these issues,
there was something created known as a switch.
Now, switches are essentially smart hubs.
And what they do is they remember who is
on each port that's connected to them.
Just like a hub, you can have anywhere from 4 to 48,
even up to 96 people connected to a single switch
if there's enough ports on it.
Now, for each port,
the switch is going to remember who is on that port.
So when somebody says, "I have a message for Jason,"
the switch is going to switch that information
from the port that it received it on
over to the port that Jason is sitting on.
And that way, only Jason will get that message.
Now, in addition to the increased security this provides,
it also prevents any of those collisions from happening
because only Jason is receiving data on Jason's port,
and it's not broadcasting out
to every other port on the switch.
So with switches,
we can have multiple people talking at one time
because the switch is smart enough
to put those people together and prevent those collisions.
This increases the speed of your network,
and increases the security of your network as well.
When it comes to switches,
we categorize these into two categories.
These are known as unmanaged and managed switches.
Now, an unmanaged switch performs its functions
without requiring any sort of configuration.
Essentially, you pull it out of the box, you plug it in,
you connect people into it, and then, it can just operate.
This is really great because it's really easy to set up.
And generally, this is going to be used in small office
and home office environments when you're dealing
with a very small network,
such as four-port or eight-port switches.
Now, if you start dealing with larger networks,
you're going to want to move up
to something a little bit more powerful.
And this is where you're going to move into a managed switch.
Now, a managed switch out of the box is going to work the same
as an unmanaged switch until you configure it.
Now, once you configure it,
you can configure a lot of different settings,
including increased security such as enabling 802.1X.
Being able to do things like MAC filtering.
Or being able to configure things
into virtual local area networks on the same switch.
Typically, if you're working in a larger office environment
that has a 24 or 48-port switch,
these are going to be managed switches.
And you're going to be able to configure these to do
a lot of different things based on your security
or operational requirements.
The next thing we want to talk about is known
as a wireless access point.
Now, a wireless access point is a device
that's going to allow wireless devices to connect
into your wired network, and effectively,
they work as a media converter,
converting the radio frequency signals
that are going through the airwaves
into that copper electrical signal
going in through a Cat 5 or a Cat 6 cable connection
into one of your switches.
This will allow you to extend your wired network
into the wireless realm.
Most of us to this point in our life have used Wi-Fi before.
And that's exactly what we're talking about.
With a wireless access point,
you can extend your wired network into the wireless realm
and allow wireless clients to connect to your network
to be able to access the services on that network
or access your internet connection
to get out to the internet.
Next, we're going to talk about a router.
Now, a router is used to connect
two different networks together.
And they're typically going to be used to make
intelligent forwarding decisions
from one network to the next based on its logical address,
which we call an IP address.
Now, this IP address or Internet Protocol address
is either going to be an IP version 4 or IP version six address
based on the network you're using, or it may use both.
Now, most modern routers are going to rely on IP,
although there are other routing protocols out there.
But these days,
almost every network relies on IP or Internet Protocol.
So that's really what we're going to be focused on.
Now, when you're dealing with a router,
you're connecting multiple different networks together.
And the most common of these is
in your small office, home office environment
when you're connecting your local area network
and your computers out to the internet,
which is going to connect through
your internet service provider.
So you're going to place your router
between your internet service provider
and your local area network.
In general, in a small office, home office environment,
you're going to get a single combination device
from your internet service provider
that includes your DSL, cable, or fiber modem,
as well as a wireless access point, a four-port switch,
and a router and firewall built into it.
This brings us to our next device,
which is known as a firewall.
And in an enterprise network,
you're going to have a firewall as a separate device.
But again, in a small office, home office environment,
often that firewall is going to be combined
into the device your ISP gives you.
Now, when it comes to a firewall,
what we're talking about is a device
that is going to be configured with different rules,
known as access control lists,
that provide us a way to scan and block traffic
as it tries to enter or leave our network.
This is the role of a firewall.
It's essentially a security guard
that sits at the border of your network.
And anything that's going to go in or out of your network
goes through the firewall and can be inspected.
And then, based on the rules you've set up,
you can either block, allow,
or drop that traffic as it tries
to enter or leave your network.
Now, firewalls are a great thing for security.
And over time, they've gotten better and better.
These days, in addition to firewalls,
we also have something known as a UTM
or a unified threat management appliance.
And this contains a firewall
as well as other features in it as well,
such as spam guards and antivirus solutions
that are combined into this single device.
But at their heart, they are still a firewall too,
and they perform those functions.
The next device we're going to talk about
is known as a patch panel.
Now, a patch panel is a device that allows you to cable
your network jacks from your wall into a central area.
And the back of this thing is known as a patch panel.
Now, a patch panel allows the cables that are running
through your walls going from your network jacks
to be able to be terminated into a single place
on a punch-down block at the back of a panel.
On the other side of that panel,
we have pre-wired RJ45 ports that we can then connect
with patch cables that are running Cat 5,
Cat 6, Cat 7, or Cat 8,
and then, connect those into our switch.
Now, you may be wondering, "Why do I need a patch panel?
"Why can't I just run these directly into my switch?"
Well, this comes down to network supportability long-term
and lowering your costs.
You see, a switch is going to cost you anywhere
between 500 and $1,000 for a decent switch
in a small office, home office environment,
or a small enterprise.
But a patch panel is only about $50.
Now, if you are plugging and unplugging things
directly into your switch all the time,
this can actually wear out those ports and break them.
And when you break one of those ports,
you can't replace them.
Instead, you need a whole new switch.
But with a patch panel, if you break one of those ports,
you can replace either that portion of the patch panel
or the entire patch panel for under $50.
This means you have a lot of savings being able to use
patch panels instead of plugging directly to your switches.
And it gives you more supportability for the long term.
In most offices and enterprise networks,
you're going to find that the wall jacks
are going to a patch panel,
and the patch panel will then be cabled to your switch.
And this helps reduce your cost
and increase your supportability.
The next set of devices we're going to talk about involve
Power over Ethernet, also known as PoE.
Now, Power over Ethernet is a feature of some switches
and other devices that allows you to supply
electrical power from a switch port
over an ordinary data cable to a power device.
Now, these PDs or power devices can be things like cameras,
voiceover IP handsets, or wireless access points.
It really doesn't matter, but the point is,
you can use that single cable to provide
both your data and your power to that device.
And this eliminates the need to have
an electrical outlet next to that device.
Now, when you're dealing with PoE,
it comes in three different varieties.
There is 8025.3af, 802.3at,
and 802.3bt.
Now, when you're dealing with 802.3af,
this is the oldest version of Power over Ethernet.
And this means it is actually going to allow
the least amount of power to be drawn.
When dealing with 802.3af,
your power devices can only draw about 13 watts of power.
So this works well for things like voiceover IP handsets,
but not so well for other higher power devices
like a wireless access point.
Now, when you're dealing with 802.3at,
this is also known as PoE Plus.
And this allows power devices to draw up to 25 watts
instead of that 13 watts with 802.3af.
Now, the third one we have is 802.3bt.
And this is known as PoE Plus Plus, or 4P PoE.
And this can be used to supply power of up to 51 watts
for a Type 3 device or 73 watts for a Type 4 device.
This is a lot of power that's being able
to be supplied over Power over Ethernet.
Now, in all of these,
you need to have three different things
to be able to use them.
First. you need to have a switch that supports
Power over Ethernet at one of these three levels.
Second, you need the proper cabling in place
that will support this.
Generally, you want to use Cat 6 or above
to be able to support higher powers of Power over Ethernet.
And third, you need a power device.
That's the device that's going to use this data and power
coming over that ethernet cable, such as your VoIP handset,
your camera, or your wireless access point.
Now, some devices do require PoE,
and you may not have a PoE switch.
In this case, you can use an aftermarket device
known as a power injector.
Now, a power injector basically plugs
directly into a wall outlet to get its own power.
You then connect the ethernet cable
from your non-powered switch into this power injector.
And then, that injects the power onto that line
as you go out the other side
and power your device from that.
So what this looks like is a cable going from your switch,
which is a non-PoE switch, to the power injector.
And then, from the power injector to your power devices.
And that power injector is injecting that power
in the middle part of this cable run,
because you're now plugging that into an outlet
that's giving you the proper power.
The next device we have is known as a cable modem.
Now, a cable modem is going to be a device
that translates a coaxial cable signal
that's coming in as a radio frequency wave
on that coaxial cable into something
that can be used by the rest of your network.
This cable modem is going to act as a converter,
taking the signal coming in off the coaxial cable,
converting it into the electrical impulses
that can then be sent out over a normal ethernet network
using copper unshielded twisted pair cabling
that can then go into your router or gateway.
Next, we have a digital subscriber line or DSL modem.
Similar to a cable modem,
a DSL modem will also do this conversion technique,
but instead of going from a radio frequency
over a coaxial cable,
it's going to convert a signal coming in
over a typical phone line into something
that can be used by the rest of your network
over a typical copper unshielded twisted pair cable.
The next one we have is what's known as an ONT
or optical network terminal.
If you're using a fiber connection to the outside world,
then you're going to be using an ONT
or optical network terminal to terminate that cable.
When that fiber connection comes into the ONT,
it's then going to act as a media converter
and translate that from light signals coming in
off the fiber into electrical signals that can go
out a copper unshielded twisted pair cable that goes back
into your router or your gateway for your network.
And the final device we have is not really a device at all,
but more of a concept.
And it's known as SDN or software defined networking.
Now, software defined networking
or software defined networks is really a way of virtualizing
the underlying network hardware that we just talked about.
All of these routers, and switches, and firewalls,
and all these devices can be converted
into these cloud-based equivalents
that we can then interact with using software.
And this is where software defined networking
comes into play.
When you're dealing with software defined networking,
we actually break down the different layers
that a device works at,
which is the infrastructure control
and application layer into those separate layers,
and we interact with them programmatically
using software to be able to do different functions
across multiple physical devices in our networking world,
but doing it all from a software perspective.