The foundation of your network is the cabling on which everything runs. In this video, you’ll learn about different cabling types and how UTP, STP, plenum-rated, and coaxial cable is used in our modern networks.
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If you don’t have a good wiring infrastructure, then you’re not going to have a good network. It is an incredibly important part of this building block that’s used for building a network that’s going to be reliable and provide you with the highest amount of throughput.
Usually you only get one opportunity when you’re putting in the wiring in a brand new building because it’s so difficult to go back and put it in after the fact. And you’re also usually running it underneath everyone’s desk or in the ceilings. So once everybody is in and working, it becomes difficult now to work around them if you need to run new wire.
Even if you’re implementing a very large wireless network, you’re still going to need wiring to connect from your access points back to the wired network. So put a lot of thought into how you’re planning to wire your network and the type of cables that you’re going to use. You’re going to have them in place for a very, very long time.
The vast majority of our networks today are using twisted pair copper cabling. And these twisted pair cables work in something called a balanced pair operation, where we’re sending the same signal down two wires but we’re sending it at a different polarity. That’s why you’ll sometimes see the two transmit wires, but they’re marked as transmit plus and transmit minus. The same thing with the receive side.
It’s this twist in the wire that allows us to reliably get signal from one end of the cable to the other, even if something in the middle is creating some interference. We have a pair of wires, and since they’re twisted, one of those wires is always going to be moving away from the interference. And because we have them at different polarities, we can examine the two wires at the end of the run and we know that exactly the same signals across both. We can piece together what we may have lost with some of the interference and able to maintain that signal from one end to the other.
One other interesting part about this, and you can almost see in this picture, is different wires, different pairs, in that same group are twisted at different rates. That’s another way to make sure that we’re able to get data all the way through the wire and be able to piece it together at the other end.
The twisted pair wiring that’s in your wall or under your floors may be either unshielded or it might shielded. Unshielded twisted pair is UTP. There’s no special shielding on the wire at all. It’s a simple copper wire with a plastic insulator over the wire. And this is generally the most common wiring. If you look at what you’ve got connected to your computer, it’s probably going to be a UTP connection.
There’s also STP. That stands for Shielded Twisted Pair. STP adds an additional shield here. And you can see the shield right here on my STP cable. There’s even also a ground wire here so that you can ground the wire on one end as well.
These are commonly used when your in an environment where there is a lot of interference. Maybe it’s a manufacturing facility. Or maybe there’s a lot of fluorescent lights that you have to pull this wire over. So you’ll use a Shielded Twisted Pair instead. STP cables, because of the shielding, are generally more expensive. So you’ll commonly see those just used in cases where you need that extra shielding to protect against interference.
When it comes to cabling and connector standards, there’s generally two organizations that you’ll see referenced. One of them is the Electronic Industries Alliance. This is a group of trade organizations that create standards for the industry. It’s been around for a very long time.
So some of the standards that you hear like RS-232, which stands for Recommended Standard 232. Or the wiring that is in EIA Standard comes from the Electronic Industries Alliance. You can find out more about the EIA at www.eia.org.
Another common standards organization is the Telecommunications Industry Association, or TIA. This is generally a group that creates standards. You can see them creating market analysis. They have trade shows that you could attend.
And you’ll see this referred to when you start looking at the way cable might be wired. We commonly refer to the EIA TIA-568 Standard for example. You can find out more about these standards at www.tiaonline.org.
The standards are important because when you connect up wiring into your infrastructure, you want to be assured that that wiring will be able to transmit what you need across the link. If you’re planning to put in gigabit connections, you need wiring that can support a gigabit link. If you’re doing 10 gig, you’ll need probably different kind of wiring that can support 10 gig.
And so these standards have been created so that you can buy one based on a standard category of cable. This is a chart that shows Category 3, Category 5, 5e, 6, and 6A. Those are the cable categories that you’ll need to know for your Network+ certification.
Category 3 and Category 5 are deprecated, which means that we don’t use them. It’s difficult to find them. You probably can’t buy those standards anymore. Category 3 was used for 10BASE-T and it had a maximum distance of 100 meters that you could run.
Category 5 was commonly used for both 100 and 1,000 megabit connections over 100BASE-TX and 1000BASE-T. And again, it had a maximum distance of 100 meters.
These days, the standard we tend to see near the bottom of the list– and this is one that works for most of our ethernet connections– is Category 5e. That E stands for enhanced. And that is what we use today for our 100BASE-TX and 1000BASE-T. It was slightly updated from the Category 5 to be able to support those very long 100 meter distances when we were using this gigabit type of connection.
Category 6 is used for 10 gig connections and below. That is something that will support 10 gig, but only in distances from 37 to 55 meters. If you need to go the full 100 meters that we commonly see with ethernet standards, you’ll need Category 6A. And the A stands for augmented. That supports that 10 gig capability and can extend to all the way out to 100 meters.
With our cables, we have to think about a lot more than just the type of speeds that can be supported over those links. There are often health and safety concerns associated with those. For example, is there a special kind of cable you might need if you’re extending it up into the ceiling where you may be working.
In this ceiling above our heads for example, in many workplaces, there is a drop ceiling and above that there may be some duct work where air is being provided into the room for cooling and heating. And then air is being returned back to the system to be recycled through there. This duct work maybe use both for the supply and for the return.
In that case, there’s no plenum to speak of. This plenum is an area where you have air that is intermixed with the other parts of the airspace up top. So you might, for instance, have some duct work providing the air but the return air is going into a shared area where there is not only airflow, but you might have your networking cables up there as well.
If you are putting your network cables into the plenum, you may be required because of fire codes and other requirements in your area to use a plenum rated cable. This is a cable that is specifically designed around fire concerns. Our cables generally have these protectors on the outside. These covers are a PVC, or a Polyvinyl Chloride.
Well, a plenum rated cable is going to have a specialized low-smoke PVC around the outside cable jacket. It will also have a Fluorinated Ethylene Polymer, or FEP. You want to make sure that your cables are not putting out more smoke or any type of hazardous materials. And you want to be sure that they’re not going to burn very quickly if there is a fire in the building.
Because these plenum rated cables have the special jacket around the outside, they’re not quite as bendable as one that is a non-plenum rated cable. So you may not be able to bend it quite is easily or work with it as well, especially if you’re pulling a lot of plenum rated cables up above the ceiling. These plenum rated cables are important for not only the requirements that we have in our fire codes, but if there is the worst case scenario and there is a fire, you can be assured that your network cabling is not going to be creating any additional problems and you can get everyone out of the building safely.
A coaxial cable is one where there is a single wire or multiple wires down the middle. And these are straight wires, they’re not twisted like we have with our twisted pairs. They have a common axis so they are absolutely straight and next to each other.
You can see the wire conductors right in the middle of a coax cable. You’ve got this insulator around the conductor. There’s usually a metal shielding around that. And finally, the plastic jacket that helps protect it from the elements.
We commonly see this in things like RG-6 that’s used in television cables, our digital wires that are coming in for our cable modems. We also see it used in RG-59. That’s used in patch cables that we might use to patch between a link coming out of the wall into our cable modem. And if you’re doing anything with a cable modem type scenario, you’re probably going to be using a coaxial cable in your data center.