Welcome back, and in this lesson,
I want to talk in a little bit of detail
about fiber optic cables.
If you're involved with networking in any way,
then you need to be comfortable
with how they work, their characteristics,
and the differences between the various types.
Now, this matters for the real world
and if you need to work
with any physical networking services,
including AWS Direct Connect.
Now let's just jump in and get started.
Fiber optic cables are an alternative way to transmit data
versus copper cables.
Where copper cables use changes in electrical signals
to transmit data over a copper medium,
fiber optic cables use a thin glass or plastic core
surrounded by various protective layers.
The core is about the diameter of a human hair.
The cable that you can see and touch
is that core surrounded by a lot of protection.
If you just handled the core on its own,
it would be pretty susceptible to damage.
Now, fiber optic cables, as the name suggests,
transmit light over the glass or plastic medium.
So light over glass or plastic
versus electrical signals over copper.
These unique elements mean that the cable
can cover much larger distances
and achieve much higher speeds versus copper.
At the time of creating this lesson,
this can be in the regions of terabytes per second.
Now, fiber is also resistant
to electromagnetic interference known as EMI,
and it's less prone to being impacted by water ingress
into a space where the cables are being used.
In general, fiber offers a more consistent experience
versus copper cable.
And so in modern networks,
specifically those which require higher speeds
and/or larger distances,
fiber is often preferred versus copper.
You're going to see over time
fiber will gradually overtake copper
in almost all wired networking situations
as it becomes cheaper and easier to install.
It's already used
for many global networking, metro networking,
and even many local area networking applications.
So that's important to understand.
It's going to be used more and more in the future.
Now, in terms of physical makeup,
this is what a typical fiber cable looks like externally.
There are two different things that you need to think about,
and this is common with any form of networking cable
or any form of cable in general.
There's the cable choice,
which will influence the physical characteristics,
so how fast data can be transferred and over what distances.
Then you have the cable connectors,
and these generally affect
what the cable can be connected to.
So we're linked to physical ports
on the networking equipment,
but they can also influence
some of the physical characteristics
in terms of distance, ability, and speeds.
Now, I'm not going to detail
all of the different fiber cable types in this lesson.
Instead, I've included a link attached to this lesson,
which gives you a good overview
of the common cable and connector types within the industry.
Now, I want to spend a few minutes
talking about the physical construction of fiber cables.
I've talked about how the connectors are different,
but it's important that you understand
the different physical makeups at the cable itself.
Now, when we're talking about fiber cable,
you'll see it referred to using an X/Y notation.
For example, 9/125.
This defines two parts of the cable.
The first part is the diameter of the core in microns,
and the second part is the diameter of the cladding,
and that's the bit that surrounds the core.
Both of these are in microns,
and there are 1,000 microns in a millimeter.
Now let's talk about the different components
of a fiber cable,
and I'm mainly going to be covering the fiber core,
the fiber cladding, and the buffer.
And don't worry,
the functions of each of these will make sense in a second.
Now we're going to start with the core,
and this is the part of the cable
where the light is carried,
which allows for the transfer of data.
This part on 9/125 cable is tiny.
It's only nine microns across.
So if you look at the right of the screen,
you have the core,
then you have the transmit and receive optics at each side,
and the light flows through the core
along the length of the cable.
I'll talk more about this in a moment,
but the light doesn't flow in a straight line;
it's actually bouncing off the inside edges of the core,
which is why the size of the core matters.
Now, surrounding the core is the cladding,
and this is a material which has a lower refractive index
versus the core.
And this means that it acts as a container
to keep the light bouncing around inside the core.
Different types of fiber
have different sizes of core and cladding.
And both of them radically impact
the physical characteristics of the cable.
And this is where we move on
to the less important parts of the cable.
The core and cladding were directly responsible
for their physical transmission of data,
but now we're moving onto the protective elements.
So next we have the buffer,
and the buffer is the thing
which adds strength to the cable.
The core and cladding
are generally really good at helping to carry data
but really bad withstanding any physical shocks.
The buffer is a combination of coating
and strengthening materials,
such as fibers made out of other materials.
Now, don't confuse this type of fiber with fiber optic.
This is just lengths of all the material,
which is designed to absorb shocks
and give physical protection.
And this buffer is surrounded by the cable jacket,
which is the physical thing that you see
when looking at a fiber cable.
It generally has a defined color such as green,
orange, or blue,
and this generally gives some indication
on the overall capabilities of the cable.
Now, I've included a link attached to this lesson,
which details the common colors and what they mean
in terms of the fiber optic cables' capabilities.
Now, one more thing that I want to cover
before we finish this lesson,
and that's the difference between single mode
and multi-mode fiber.
The difference might seem pretty nuanced,
but it's really important to understand.
Let's start with single-mode.
single-mode generally has a really small core
and it's often eight to nine microns in size,
and it generally uses a yellow jacket,
but this isn't always the case.
Now, because of this tiny core,
light generally follows a fairly single and straight path
down the core.
There's generally very little bounce,
and so very little distortion.
single-mode fiber generally uses lasers,
and so it's more expensive
in terms of the optics versus multi-mode.
single-mode, because of this lack of distortion,
is great for long distances
and it can achieve excellent speeds
over these long distances.
Now, it's not the fastest type of fiber cable,
but if you need a combination of high speeds
and long distances, then it's by far the best.
Single mode fiber can reach kilometers
with no repeating or amplication
and can do really high speeds at those distances.
Generally, in production usage, this is 10 gig and above.
single-mode fiber cable itself
is generally cheaper than multi-mode fiber,
but the transceivers,
so the things which send and receive light,
are more expensive versus multi-mode,
but this is changing over time,
and this will probably mean more and more single-mode usage
within most business applications.
Now multi-mode cable generally has a much bigger core
and often uses either an orange, an aqua,
or other-colored jackets.
Now, the bigger core means that it can be used
with a wider range of wavelengths of light,
generally at the same time.
For simplicity, think of this as different colors of light
traveling down the same fiber cable.
So these different colors can be sent at the same time
and don't interfere with each other.
More light means more data.
So multi-mode tends to be faster,
but that comes with a trade off
because this leads to more distortion
over the light over longer distances.
For that reason, multi-mode, historically,
has been used for shorter cable runs
where speed and cost effectiveness is required.
Now, multi-mode generally has cheaper LED-based optics
rather than the more expensive laser optics
used within single-mode fiber.
multi-mode fiber cable will generally use the prefix OM,
so OM2, OM3, OM4, and so on,
each improving the previous one's capabilities.
A multi-mode, as I mentioned before, has a larger core.
At a high level,
the type of cable you decide on
is determined by the distances
that you need to transmit data and the speed.
So single mode is just more sturdy.
There's less distortion,
and it can do better speeds over higher distances.
And as the optics price has come down,
I suspect more people will use single-mode
even for shorter distances.
Now, one final thing I want to cover
before we finish up with this lesson,
and that's fiber optic transceivers.
Now, these are generally the things
which you plug into networking equipment
which allows the networking equipment
to connect to fiber optic cables.
They're known as SFP transceiver modules,
also known as SFP or MINI GBICs.
And this stands for single form-factor pluggable.
Now, these are the things
which generate and send or receives light
to and from the fiber optic cable.
So these plug into networking equipment.
These have optics inside which generate the light
or can detect the light.
And these are used to translate from data to light
and from light to data that networking equipment can use.
Now, transceivers are either multi-mode or single-mode,
and they're optimized for a specific cable type.
So you generally buy a transceiver
that's designed to be used with a certain type of cable.
And the transceivers will need to be the same type
on both sides or both ends of the fiber optic cable.
Now, when you're talking
about the connector type and the cable,
you're generally going to see terms such as 1000BASE-LX,
10GBASE-LR, or 100GBASE-LR4.
And these are often specified by vendors, such as AWS,
to give you an idea on the type of cable
and the connector that you need to use
to plug into their equipment.
So in the case of AWS Direct Connect,
the supported types are 1000BASE-LX, 10GBASE-LR,
and 100GBASE-LR4.
Now, unless you're doing
the advanced networking specialty level of study,
you don't need to remember these from memory.
If you are doing the advanced networking,
I would recommend that you try to commit these to memory
because it might help you gain an exam mark within the exam.
Now, at this point,
that's everything I wanted to cover at a high level
about fiber optic cables and transceivers.
And once again, I've included some links
attached to this lesson,
which go into a little bit more detail
if you're interested.
At this point, though, that's everything I wanted to cover.
So go ahead and complete the video.
And when you're ready,
I'll look forward to your joining me in the next.