[Instructor] In this lesson,
we're going to discuss fiber media.
Now, fiber media is used
to transmit data using light instead of electrical impulses.
And this type of fiber optic technology represents
a significant leap in data transmission capabilities
compared to our more traditional,
copper media based networks.
Fiber optic cables use light typically from LEDs
or lasers to transmit data over glass or plastic cables.
Fiber media has several key advantages over copper media,
including an immunity to electromagnetic interference
or EMI, the capability
to transmit data over much longer distances
without significant signal loss
and the ability to reach much higher data transfer speeds.
Fiber media is great
because it is fully immune to the effects of EMI,
because EMI can only be generated by electrical signals
and it can only affect other electrical signals.
Since fiber media relies on light to send its data,
that light is not going to be affected
by any outside electromagnetic interference,
and it doesn't require a shielded cable
to overcome the effects of EMI
like a twisted pair cable might.
When it comes to data transmission over longer distances,
fiber optic cables are also superior to copper media.
With twisted pair of copper cables,
you're limited to about a hundred meters
due to the signal degradating over time
based on the resistance of the cable.
If you're using coaxial copper cables,
you can extend that to about 300 meters in length,
but it will still degradate over time
and the signal be reduced
and no longer function after 300 meters.
Now, when you're using fiber optic cables,
on the other hand though, you can span not just hundreds
of meters, but you can also span hundreds of miles
with a single fiber optic cable.
This makes fiber optic cables ideal for a wide range
of applications from your local area network connections
to transcontinental data transmission
using underwater fiber optic cables.
Now in terms of speed,
fiber optic cables can reach blazingly fast speeds
as compared to our copper cables.
Most copper media is going to reach a maximum speed
of around 10 gigabits per second
and covering up to about a hundred meters in distance,
but a fiber optic cable can reach
much higher data transfer speeds
even when crossing tens or hundreds of miles.
In fact, all the way back in 2012,
the Japanese telecommunications company NTT was able
to send data at one petabit per second.
Fiber is used in extremely fast networks,
and it's usually not the fiber cable
that becomes the bottleneck
or limitation in our networks anymore.
But instead, it's going to be our networking equipment
such as our routers, our switches, and our end user devices.
For this reason,
most business class networks are going to use fiber
that are operating at around 10 gigabits per second,
but that is more of a cost benefit decision
than an actual technical limitation
of the fiber cables themself.
You're going to find that most fiber optic networks
are operating in this range of 10 gigabits per second,
or maybe these days,
up to about a hundred gigabits per second
due to those networking hardware limitations
and trying to manage the business' overall cost
to deploy their networks.
So if fiber is so great,
why aren't we all using it in every single network?
Well, there's really two main drawbacks when it comes
to fiber, and these are cost and complexity.
Now, fiber optic media is actually pretty expensive,
especially when compared to copper media.
For example, a 25 foot fiber optic cable costs around 15
to $20, where an equivalent 25 foot,
copper twisted pair cable would cost us only around $5.
But the network equipment to support the fiber instead
of using copper is also going to be much more expensive too.
The other consideration is that the complexity involved
in using fiber optic cables is much higher.
Fiber optic cables are actually much more difficult
to work with than using a twisted pair
or coaxial copper cable.
In fact, when I used
to teach this course in a classroom environment,
I would actually give my students their own kit
to create a CAT5e or CAT6a twisted pair of cable.
These kits included a crimper, connectors, a cable tester,
and about a hundred feet of cable for them to use,
and the entire kit cost me around 10 to $15 per student.
Then within about 10 minutes of me teaching my students
how to create their own cables, they could effectively build
their own copper patch cables themself
and take it home with them after class.
Now, fiber though is much more difficult to work with.
It's going to require special tools
and training to learn how to make fiber cables
or to repair broken fiber cables.
In my experience, it actually costs between five
and 10 times more to run a fiber cable
within an office building as it does to run a copper cable
across a similar distance.
In fact, even the tools are more expensive.
As I said, I can buy an entire copper cable kit
for about 10 to $15,
but a fiber kit will cost me about 150 to $250.
So it is much, much more expensive.
Now, even with these drawbacks of the higher costs
and fiber being more difficult to work with, though,
fiber optic cables definitely have a place in most
of our enterprise networks.
So we're going to have to spend a little bit
of time going over the two main types
of fiber optic cables that you need to be aware of.
These are single-mode fiber and multi-mode fiber.
Now, first we have single-mode fiber,
single-mode fiber, also known as SMF, is designed
for long distance communication.
It features a small glass core
and is typically around 8.3 to 10 microns in diameter.
Now, to put that in perspective for you,
the diameter of a human hair is only 17
to 180 microns in diameter depending on the person.
So even at its smallest and thinnest,
a human hair is still about two times larger
than the fiber core of a single-mode fiber.
And at its thickest type of hair,
we're actually talking about 18 to 20 times as large
as a single fiber inside of our fiber optic cables.
Now, due to this very tiny fiber core,
the light can only travel down a single path
without causing much dispersion of that light,
which is why we call this type of fiber a single-mode fiber.
Because the light travel down a single path.
This type pathway for the light beam enables
the single-mode fiber to carry signals over longer distance
of up to tens or even hundreds of miles.
This makes single-mode fiber the preferred way
for backbone installations in large networks,
as well as for connections
between different network segments
that are spread over vast areas of land.
If you need support for high bandwidth over long distances,
you really should be considering the use
of a single-mode fiber for your network's application.
Second, we have multi-mode fiber.
Now, multi-mode fiber
or MMF is tailored for shorter distances
because there's a larger fiber core size
that ranges from 50 to a hundred microns.
So again, this is a very small core,
but it is still five times larger
than a single-mode fiber core was.
Now, because of this larger fiber core,
it's going to allow light to travel in multiple paths
or modes, which can be beneficial
for transmitting data over shorter distances.
But this larger core size does mean that there is more room
for dispersion of the light signal to occur,
and this will then effectively limit
the transmission distance that you're going to be able
to achieve over a multi-mode fiber cable.
Now, the reason people use multi-mode over a single-mode is
really cost because they have a larger core, they're cheaper
to manufacture than those with a smaller core
because it uses less precise equipment.
Now, multi-mode fiber cables are commonly going to be used
within buildings or across smaller campuses
or business parks because they're suitable
for connecting servers and switches
or interconnecting network equipment
within a single data center.
If you need higher data rates over shorter distances,
then a multi-mode fiber is a good choice
to consider over using a copper media cable.
Now, when I refer to a shorter distance in terms
of fiber optic cables,
what I'm really talking about is anything under
about 2000 meters in length, which is about two kilometers
or about one mile.
So this is still much longer
than our traditional copper cables,
but not up to the several hundred miles
that could be covered by a single-mode fiber cable.
So I usually consider multi-mode fibers for use
in the same places where you would
normally use a copper patch cable.
For example, you may use multi-mode fiber to connect routers
and switches, switches to switches, or switches to servers.
Any place you'd normally use a patch cable
or even a cable run between your patch panel
and your wall jack could be a good place
to use a multi-mode fiber instead.
That way, you can get higher speed
and you won't be subject
to any electromagnetic interference.
So you may be wondering,
how can I tell a multi-mode fiber
from a single-mode fiber apart
when I'm working as a network technician?
Well, the easiest way for you to identify each of them is
by the color of the cable itself.
Now, if you see a cable that has a yellow plastic wrap
or sheath around it, this is going to be considered
a single-mode fiber or an SMF cable.
If the cable has an aqua blue
or orange color sheath around it,
then it's going to be a multi-mode fiber or MMF cable.
Now, this is a standard
that almost every cable manufacturer is going to follow,
because otherwise it becomes pretty impossible
to tell the difference with your own eyes because the size
and the diameter is still so much smaller than a human hair,
and so we can't really see that difference
between those two cables
by just looking at them if we don't have that color scheme.
So remember, there are two main types
of fiber optic cables out there, single-mode fiber,
and multi-mode fiber.
single-mode fiber, also known as SMF,
has a smaller fiber core, which makes it highly efficient
for long range transmissions
by offering higher bandwidth over those longer distances,
the smaller fiber core does force the light
to travel down a single-mode fiber's core using
a singular path that prevents diffusion
of the light being transmitted down that cable.
Multi-mode fiber on the other hand, which we also call MMF,
has a larger fiber core that will limit the distance
that your data can be transmitted
since that light signal can bounce
around the inner fiber core more
and becomes subject to that light diffusion.
Because of this, multi-mode fiber does tend
to be less expensive to buy
and install than a single-mode fiber would.
So a lot of network designers try to implement solutions
that allow them to use multi-mode over single-mode
whenever it's possible because it's easier to work with
than a single-mode fiber
and a lot cheaper to install.
Multi-mode fiber is considered ideal
for internal network infrastructures
such as within an office building or data center,
or as a replacement for copper patch cables
in a high security environment or any environment
that may be subject to higher levels
of electromagnetic interference.