For most of us, the foundation of our networking
is done over copper cabling.
If you want your network to run well,
then you want to be sure you're using the right kind of cabling
and that your cabling infrastructure is
working exactly as expected.
If you're building out a new area
and you're putting in fresh cabling,
then you want to be sure all of that
cabling installation is done exactly to specification.
Most of what we do on our networks
are going to be using these copper cables.
So we want to be sure that everything works perfectly.
If we look inside our cables, we'll
see that there are different pairs of cables that
are twisted around each other.
These are twisted pair cabling.
These are using balanced pair operation,
which means we're sending the same signal
over each one of those pairs.
But one of those signals will be positive
and one of those signals will be negative.
It's this twist that allows us to receive information
over this cable, even when there might be interference.
That's because this twist will be constantly
moving away from any interference
as the signal goes through the wires.
We can compare these opposite signals
on the other end of the wires to see exactly
what the value should be.
Additionally, you'll notice that the different pairs will also
have different twist rates.
This means we'll have a different set of values
across different pairs, even if they
are subject to the same interference
as the signal's going through.
One of the most popular types of twisted pair cabling
is the unshielded twisted pair, or UTP.
And you can see in this picture, this UTP
has no additional shielding around either all of the pairs
or any individual pairs.
You can also get cabling that is shielded twisted pair, or STP.
This additional shielding helps protect
against any additional interference.
There may be shielding on the overall cable,
and there could also be shielding on individual pairs
of the wires.
You'll find that shielded twisted pair also
includes some grounding wire, so you
can make sure that this cable's properly grounded.
If you were to look at the specifications of the cable--
or even the printing that's on the side of the cable--
there will be a number of abbreviations
that could be used.
If it's an unshielded cable, it will
have a U, specifying that this is unshielded.
One that has an S will mean that it is shielded,
but it will be a braided shield.
And a foil shield will be specified by placing
an F as part of the cable type.
You'll see this spelled out showing
the overall cable shielding.
There'll be a slash, then there will
be the shielding type for the individual pairs,
and then a TP to specify the twisted pairs.
So if a cable has a braided shield around the entire cable
and then a foil around each of the individual pairs,
you should see S/FTP on the side of the cable or the box
the cable comes with.
If the shielding is like the picture here,
where there's foil over the entire cable
but no shielding over the individual pairs,
then that will be F/UTP.
you can often look on the side of the cable
to understand how things might be configured on the inside
without having to strip any of the wires back.
For example, this cable has S/FTP
written on the cable itself, which
means there's a shielded braid around the entire cable,
and then each individual pairs of cables
has a foil shielding around those.
That's where we get the braided shield slash foil twisted pair.
There are a number of different groups
that set standards for these network cables that we use.
One of these is the EIA.
It's the Electronic Industries Alliance.
And they set a number of standards for the industry.
You can see their standards starting with an RS or EIA,
and you can see all of their standards on their website
at eia.org.
Another organization that sets standards
is the TIA, or the Telecommunications Industry
Association.
One of the larger sets of standards
that we use for cabling is the EIA TIA 568,
which is the commercial building telecommunications cabling
standard.
And international standards would come from the ISO IEC
11801 cabling standards that set standards
for everyone in the world.
Not all twisted pair cables are the same.
Some twisted pair cables use a different type of copper.
Some will use a different number of twists.
And a cable may be shielded or unshielded.
There is a set of standards that specify the minimum category
of cable that you need to be able to send
a certain type of signal.
For example, category 3 is one of the older types
of category cables that you may still
see in many organizations.
That's designed to support 10BASE-T, or 10 megabit
ethernet.
And it's supported that over a distance of 100 meters.
There is also category 5 cable that supports 100BASE-TX,
and 1,000BASE-T 100 and 1,000 megabit communication.
And it can support those over 100 meters.
Both category 3 and category 5 are no longer available.
Usually the minimum type of cable that you'd see available
is category 5e, and the E stands for enhanced.
There were minor changes between category 5 and category 5e.
And you'll notice that we support exactly
the same ethernet standards over both category 5 and category
5e.
And category 5e does support gigabit
ethernet up to 100 meters.
When we increase the speed of ethernet
to 10 gigabit over copper, we created the 10GBASE-T standard.
And category 6 cabling can support 10 gig over copper
from 37 to 55 meters in length.
If you're using category 6a, which
is an augmented version of category 6,
you can support this 10 gig over copper
up to distances of 100 meters.
And category 7 is a relatively new category
for twisted pair cabling.
It adds stricter specifications for cross-talk,
and the individual wire pairs are
shielded, along with the entire cabling being shielded.
It also supports 10 gig ethernet up to 100 meters in distance.
In our homes and businesses, there's usually a ceiling.
And above that ceiling, we might have air supplies.
And this is where we would also run our network cables.
If there are air docks that are providing the air for your air
conditioning and also air ducts that are returning the air,
that means there is a non-circulating air
space, or no-plenum above your ceiling.
But in many environments, there may
be air that is being supplied through air ducts.
But the return air space is going into a shared area where
you have all of your building air circulation
along with all of your cabling.
This area is called the plenum.
There are a number of fire regulations associated
with this plenum area.
That's because if there is a fire,
this open area will be providing air
to help feed any type of fire that may be in the plenum.
You also have to think about what you're
putting in the plenum and how it may react to fire, especially
giving off types of smoke and any type of toxic fumes.
So if you're running cabling inside of your plenum,
you have to make sure you're using
the right kind of cabling.
A traditional cable will have a jacket around it made
a polyvinyl chloride, or PVC.
If you're putting cable in a plenum,
you may want to use a fire rated cable jacket.
This is one that is made of fluorinated ethylene polymer,
or FEP.
Or it may be a low smoke version of PVC.
PVC is relatively flexible.
You may find that some of the fire rated or plenum rated
cable may not be quite as flexible as the other types
of cables that you're using.
If you're planning to put anything in an area
where there could be a concern with fire,
then you'll probably want to use a plenum rated cable.
Although twisted pair is a very common form of network cabling,
we also use coax cable for some of our copper cabling.
Coax has a wire conductor right in the middle of the cable.
This coax cable has insulation around that conductor, metal
shielding around that, and finally, a plastic jacket
to protect the entire cable.
If you're bringing in television or an internet modem,
then you'll probably be bringing in RG-6 coax cable.
If you're working in a smaller area,
you may be using RG-59 as coax cables.
These are not designed to be used over long distances,
but they do make very good patch cables.