CompTIA Network+ N10-008 – Media and Cabling Distribution

1. Media (Copper)

Now, in this lesson, we’re going to talk about the different types of media. There are three categories of media: copper, fibre optics, and wireless. In this lesson, we’re going to talk specifically about copper media, though. Each of these categories is divided into subcategories and each of them has different specifications and uses.

So sometimes I’m going to use copper media. Sometimes I’ll choose to use fibre optics because each one has its own benefits and drawbacks. Now, when we talk about copper media, the first and oldest one is coaxial cable, or coax. This has an inner insulated conductor or centre wire that’s going to pass all of the data, as you can see there on the screen labelled as the centre core. We also have an outer shell on this that has a braided metal shield to help shield it from data transmission leakage and provide electromagnetic interference resistance because of this shielding. So on the outside, we have this plastic jacket, followed by a metallic shield, and then some sort of insulator.

And inside is that wire, where the data passes. Now, where would you find coaxial cables? There are two main types that we’ve seen over the years: the RG-6, which is commonly used by local cable companies to connect your homes, and the CAT-5, which is used by telephone companies. It’s a very thick version. And then inside your home, you use RG 59. And this is what’s going to carry composite video between two nearby devices. So if you have cable TV or satellite TV in your house, you probably have RG-59 cables running from your cable or satellite box to your TV. That’s the most common one. And as you can see here on the screen, they do have that screw-type connector to connect it to, but we’ll talk more about those in a second.

Now, what kind of connectors can you have? Well, there are two main types of coaxial cables. BNC, which was once widely used in networking, is now referred to as a bayonet neil concealment or British naval connector for BNC. Now, most of the time, we’re just going to refer to this as BNC. It was used for the old 10-base-2 networks in the early days of Ethernet. Back in, it would work by pushing and twisting on to lock into place. And it was just a simple half-twist maneuver. not the screw type that we use in our cable TVs. The cable TV screw type is what’s called an “f” connector. This is what we typically see in cable modem TVs for video applications. And it was visible at the bottom of the screen. The next one we have is what’s called a twisted-pair cable, which is another type of copper cable. Now, this is the most popular land media type there is. So if you’re plugging in a network cable to your laptop or desktop, this is what you’re using. Inside of this cable, there are eight individually insulated wires that are going to be inside.

And each of those is twisted into a pair, as you can see here on the bottom of the screen, which is why we call them twisted pair cables. So we have four pairs of two wires each. Each pair is twisted, and the more twists you have, the less prone it is to EMI because that twist is actually going to counter the electromagnetic interference. So there are two types of twisted-pair cables. There are two types of UTP: STP and UTP. UTP stands for unshielded twisted pair. STP stands for shielded twisted pair. Now on this screen you can see unshielded twisted pair. And I have a big blown-up diagram here for you to see it. Notice it’s just the wires that are twisted, and they’re covered in this plastic jacket that’s shown by that grey jacket. The number of twists is going to determine how much EMI can be blocked. And as you look at it, a cat six or a cat seven is going to have more twists per inch than a cat five. UTP is much cheaper than STP because there’s no metal being used. It’s all plastic materials except for the copper wire on the inside.

This is the medium of choice for most countries, and it is very easy to work with and very easy to use. It will bend very easily as you’re pushing it through ceilings and walls. As a result, UTP is almost exclusively used in many, many networks. STP stands for shielded twisted pair. Now, if you notice on the diagram here, it looks just like UTP, with the exception of that metal foil wrapping each pair of wires and then this braided metallic shield wrapping around that as well. Now the wires are twisted in pairs just like before, but they have this metal shielding that helps minimize EMI even further. The outer shielding is going to minimize EMI, but because of all the extra metal put in, it’s going to cost more than an unshielded twisted pair. Other than that, they operate the same. They will have the same amount of distance limitations, they will have the same amount of type of connectors being used.

And the wires on the inside are the same, with the exception of that shielding. Twisted-pair connectors There are three main ones that we’re going to talk about. RJ-45 is the most commonly used in networks. It is an eight-pin connector and really looks like a fat phone jack. You can see it here on the screen with that blue cable. This is what Ethernet uses. Now, Ethernet only uses four of the eight pins. The other four are just reserved for future use, but they can be used for other applications and on the same cable. And we’ll talk about that later on when we get into things like power over Ethernet. Now the second type of connector we have is what’s called an RJ eleven.

Now RJ-11 is the one we see with the white cable; it’s a six-pin connector, and usually only two or four pins are used. And this is commonly found in phone systems that only use two phones—one for ringing and one for signaling. Now DB9 or DB25, which is what we use for RS-232 cables, is shown on the bottom of the screen. And it’s called a DB-9 because it has a nine-pin D subminiature connector. Now, these are used for asynchronous serial communications, usually connecting an external modem. And that’s what you’ll use those for. As previously stated, RJ 45 will be used in the majority of networks. Now you may be wondering, “What does RJ stand for?” It actually stands for Registered Jack. Not that you’ll be tested on it, but it’s an interesting side note. When we talk about twisted-pair cable throughput, we’re referring to how much bandwidth can pass through this thing.

So, we’ll have a chart here on the screen that will range from Cat 3 to Cat 7. Cat 3 operates at ten megabits per second. Cat 5 goes from one to 100 megabits per second. Cat 5, E, goes up another one to 1000 megabits per second, or one gigabit per second. Cat Six remains at one gigabit per second. Cat six, A, goes up to ten gigabits per second, and cat seven remains at ten gigabits per second. Now, do you have to memorise this chart?

Yes, you do. Here’s an easy trick to it, though. Notice that all of these cats, from three to seven, have the same maximum distance. They are all at 100 meters. So, when it comes to throughput, remember that cat three equals ten. Cat Five goes up by adding a zero to 100. Cat Five E climbs another rung by reaching 1000. And then you can go from there, right? And you can see this pattern that’s going to evolve. But you will have to memorise what speed you have for each type of category table because you will get questions on that in the exam on that. Now, we’ve talked about these cables and we’ve talked about the way the ends are wired, but we need to talk about the way the ends are wired, the pin, just a little bit more in depth because there are test questions on it.

So when we talk about a straight-through patch cable, it means that both ends and both pinouts are exactly the same. The five, six, eight B standard is the preferred standard for wiring buildings and using that in all cables and jacks inside of a building.

And what that will look like is, as you can see here on the screen, pins one through eight will have the color scheme of white, orange, orange, white, green, blue, blue, white, green, white, brown, brown. And by having that on both sides of the cable, this is called a straight-through patch cable. Now this is going to connect something called a DTE to a DCE. Now what is that? Well, a DTE is data-terminating equipment, like laptops and desktops. They’re going to connect to DC data communications equipment, which includes things like switches, routers, and modems. And so anytime you have these communication devices, you would have to connect them straight through a cable to a terminating device. If I wanted to connect a switch to another switch, since they are both data communications equipment, I would have to use a different type of cable called a crossover cable. And a crossover cable is going to take the send and receive pins of the cable and swap those pin outs. So, as you can see here on the screen, we’ve changed the colour scheme from one side to the other.

And we have five, six, and eight B on one end and five, six, and eight A on the other. This is used to connect a workstation to another workstation. And if you’re connecting a switch to another switch, you would also use a crossover cable, with one caveat. Modern switches support something called MDIX, which is an automated way to electronically simulate a crossover cable connector. So with modern switches that support MDIX, you can still use a straight-through cable or a patch cable, and it will work just fine. We’ll talk about this more when we get to troubleshooting way towards the end of the class, because it is something that is going to be covered in your troubleshooting section where there are two switches and they’re not communicating, and it’s because somebody’s using an Ethernet cable or a straight-through cable and the switch doesn’t support MDIX. If your switch doesn’t support MDIX, you have to use a crossover cable to make them talk. Now, when we look at the pinouts, we’re going to look at five, six, and eight A and five, six, and eight B.

Remember, five, six, eight B is the standard that we use in all interior wiring and both ends of a straight through cable. But if we want to do a crossover cable, we’ll have B on one side and A on the other. And you can see here on the screen where we change out pins 1, 2, 3, and 6 and swap them so that we have our transmit and our receive in a different place so that we can talk over that crossover cable. Essentially, your orange and your green pairs are going to swap places. Now, do you have to memorise this? Yes, unfortunately, you do. In the real world, if you don’t have it memorised, I know a lot of network technicians who will carry this chart in their pocket and pull it out whenever they’re making a cable. But for the exam, you are going to be required to know this. They might ask you to “spin out a 5, 6, or 8 B connector” as a test question. for me, and you’ll have to drag and drop the colour of wire to the right pin. So if you can remember this chart, where you have the pin number and the colour for each of the A and B standards, you’re going to do great on those questions. Now, the next piece of cabling we have to talk about is Plenum versus non-Plenum.

Now, what does that mean? Well, plenum cable is a special coating that is put on a UTP or STP cable that has this fire-retardant outer insulator. As a result, if the cable catches fire, it will emit fewer dangerous fumes. If you plan to run cables in areas where you can’t see them, such as ceilings, walls, raised floors, or air ducts, you must use Plenum cableper laws and county requirements in your state and county of residence on the exam. This is a safety issue. So keep Plenumis in mind for things you can’t see. Now, if I’m running a cable from my computer to the wall outlet, I can see that cable the whole time. I can use a non-Plenum cable. Non-plenum cable is known as PVC. It is a normal UTP or STP-rated cable, and it can be used anywhere that you can physically see it. But again, you cannot put non-Plenum cables in ceilings, walls, raised floors, or air ducts. That is a big, big no-no and a dangerous thing for the safety of your networks and your people.

2. Media (Fiber)

fibre optic cables So the second type of cable we’re going to talk about is fibre optic cable. Now, fibre optic cables are going to use light from an LED, a light-emitting diode, or a laser to transmit information through a glass fiber. This is great because it’s immune to EMI, and because you’re using light versus electricity, it can go an extremely long distance distance.

Whereas our copper cables (Cat 3 through Cat 7) could only travel 100 meters, fiber optic cables could travel hundreds of metres or even hundreds of miles. Now, the benefit to this is that it has a greater range, and we can cover vast distances. But in addition to that, because we can turn lights on and off so quickly, we can actually carry a large amount of data. So instead of talking about things in terms of ten megabits per second or ten gigabits per second, we can talk about things in terms of ten and 20 terabytes per second on extremely fast networks. Now, what are some drawbacks to fiber? It’s really expensive, and it’s hard to work with, but we’ll talk about that more in this lesson.

Now, there are two types of fiber. There are two types of MMF and SMF. MMF is multimode fiber, and SMF is single-mode fiber. We’ll talk about those more in this lesson, too. Now, the first one we have is multimode fiber, or MMF. This one is used for shorter distances than single-mode fiber. It has a larger core size than glasses, and it allows for multiple modes of travel for the light signal. So the core size is 62.5 microns, which I know sounds really, really small. And as you can see in the upper right corner of the screen, it’s a very small diameter, but it’s actually large compared to single-mode fibers. The common use of multimode fibres is where you’d normally use a patch cable. So things like connecting routers to switches, switches to switches, or switches to servers—any place that you would normally go ahead and put a crossover cable or a straight-through cable is a place that you could use a multimode fiber.

So again, small distances—a couple hundred meters. Now, when you get to single-mode fibre, this is your long haul. These are things that will COVID over much greater distances. It has a much smaller core, and because of that, it only allows a single mode of travel for the light signal. So when you see these big fibre rolls being put out throughout your community, those are single-mode fibers. The core size here is ten microns. So it is one-sixth the size of a multimode fiber. And we can use it to connect switches over long distances or routers to switches over long distances. Now, do you have to memorise the size of the core for either of these? No, I’m just giving you that information so you have an idea of what we’re talking about. Single mode is much smaller, so only one direction of light can be traveling.

When you have multimode, because it’s larger, the light can bounce around more. Now, regardless of whether you’re using multimode or single-mode fiber, you have to have an end on this connector somewhere, and that’s what these fibre optic connectors are used for. There are four types of connectors that are commonly used in our networks. SC, ST LC, and Mtrj are available. For the exam, you need to be able to see them and identify which one is which.

Now, how do you remember which one is which? Well, I’m going to give you some memory aid. Let’s look at SC, which stands for subscriber connector. Now what do I like to call it to remember it? Well, we call it the stick and click method. And the reason why is because, as you can see on the top of the SC, there’s that little ridge right by that white area. And when you push it into your network card, you’re actually going to hear a little click sound. And so that is why we call it the “stick and click.” So SC (stick, click, st) stands for Straight Tip Connector. And the way I remember this one, I call it the Stick and Twist for St. The reason why is that it works like a BNC connector. You push it into the card and then twist it half a turn to the right to lock it in place.

So stick and twist. The next one I have is the LC, which is the Lucent connector. Now this one I don’t have as a cool little mnemonic for like that. But if you notice, it looks like you have two SC connectors connected together, and that’s really what it looks like. So the Lucent connector does have two clicks and two snaps, but they’re tied together. So when they’re together, they’re okay. And then we have MTRRJ. Now this looks a lot like an LC, but much, much smaller. And we usually use this one when dealing with routers because it is roughly half the size of the other connectors. And so if I have a switch that has 24 ports, I would use MTRJ because they take up less space to be able to connect into those switch ports. Now the next thing we’re going to talk about is these connectors themselves. So we talked about the fact that we have this end, and it’s this glass connector. There are two ways to build them. They can have an angled physical contact connector, such as the APC shown at the top, or a UPC, or ultra physical contact. Now I don’t know if you’re going to get a lot of questions on the exam about APC or UPCbecause honestly, it wasn’t covered back in the six days. Now in the new seven exams, it is part of the exam objectives, so you may see one or two questions on it. So if you’re remembering, APC is an angle connector. You can see it has a 45-degree cut, whereas UPC is more of a flat end-to-end connector. And you’ll notice that the SC prefers APC while the Mtrj prefers UPC. But really, I would focus on knowing what those four fibre connectors look like on the last slide, because that’s where you’re definitely going to see some questions.

3. Transceivers

Transceivers. So in the last lesson, we talked about fibre optic cables, and the lesson before that, we talked about copper. But what’s the difference? Well, when we compare copper versus fibre optics, we really compare them in four main areas: the speed of the bandwidth, the distance it can cover, how good it is against EMI, and what kind of security it gives you. Well, when we deal with fibre optics, it has a lot of advantages. It has a higher bandwidth than copper and can cover much longer distances than copper. It’s immune to EMI because it’s not using electricity; it’s using light. And it has better security because it’s much harder to tap into and read those signals without using extremely expensive equipment. Now, copper, on the other hand, is less expensive.

It is very easy to install, and the tools to use it are so cheap. You can purchase 100 RJ-45 connectors on Amazon for around $10. You can get a crimper and an atester for less than $10. When you try to do the same thing with fibre optics, it will cost you several hundred dollars. Now, when I look at fibre versus copper, I want to remember that fibre goes very long distances—40 plus kilometres or more, 60 or 70 terabytes or more. Copper, on the other hand, travels over short distances. You can’t go more than 100 meters, and you can’t get more than ten gigabits even with a Cat 7 cable, the latest cable. It only operates at ten gigabits per second, which is sufficient for most home and office networks. But for long-haul circuits, fiber definitely outweighs copper. Now, when I have fibre coming in for a long-haul circuit, how can I transfer that into copper? Well, that’s where media converters come in.

They convert media from one format to another, like fibre to copper or copper to fiber. These are considered layer-one devices because all they do is take the signal, convert it, and repeat it right out. So, as you can see here on the screen, I have two sets of connectors for fibre stick and twist, a transmit and receive cable coming in, and a RJ-45 Cat-5 cable coming out. And that’s what we’re using it for: we take the input from the fibre and the output from the copper, and we can mix them going back and forth between the two. So media converters are used to convert Ethernet to fibre optics, fibre optics to Ethernet, coaxial to fiber, fibre to coaxial, or any other layer-to-layer conversion that you may need to do. Transceivers are devices that send and receive data. They can be bidirectional or duplex. If they’re bidirectional, they take turns communicating. So, if you’re used to using a walkie-talkie when you were a kid, you’d pick up the walkie-talkie, press the button, and say something while you were talking.

Your buddy who had the other walkie-talkie could not key up and talk because it’s bidirectional communication. One person talks, then the other person talks. We refer to that as “half duplex” because you can only use half of the bandwidth at a time. Now, the other way we can communicate is using what’s called duplex. Now, duplex allows the devices to communicate both at thesame time and we call this full duplex mode. So if you pick up a telephone and you and I are talking, you can talk and I can talk, and we can even talk over each other because we can both talk at the same time, whereas with a walkie-talkie we weren’t able to do that. Now, with transceivers, we use them in our networks a lot. Transceivers are devices that both transmit and receive data. One example of that is what’s called a GBIC, and this is used in our routers and switches. This is a standard hot-pluggable gigabit Ethernet transceiver that can then take in copper or fibre as its connector. The next one we have is what’s called an SFP, or small form factor pluggable.

And you can see how small it is compared to a jeebic. This is a compact and hot-pluggable optical module, so it uses fibre and can be pulled in or out without turning off the router or switch. This is a transceiver, and it supports up to 4.25 gigabits per second of speed. And it’s also known as a “mini GBIC” because it’s about half the size of a standard GBIC. The next transceiver you might find in your networks is called an SFP Plus, which is just a faster version of a small form-factor pluggable. It supports up to 16 gigabits, so almost four times as much speed. The next one we have is what’s called a “quad small form factor pluggable,” or QSFP. And this again is an optical module transceiver, just like an SFP Plus, an SFP, or a GBIC. The big difference here is that it goes faster; it can support 100 gigabits per second. And that’s the idea with transceivers. All of these are devices that can transmit or receive data as well as convert media from copper to fibre or fibre to ones and zeros and whatever else we require within our network.

4. Cable Distribution

Cable distribution. So now that we’ve gotten our copper and fibre cables and all of our connectors and figured all that out, how are we going to run them inside of our buildings? Well, that’s where cable distribution systems come into play. A cable distribution system is an organised system that’s hierarchical in nature, so we can figure out exactly where those cables should be so they’re safe, secure, and functional for us inside of our buildings.

Now, there are lots of different components. The cable enters your building through this entrance facility. And that comes from your telecom provider, such as your fibre or cable connection, and you have your main distribution frame. And you can see that on the diagram, it comes in on the bottom floor and goes to our main communications center. From there, we have cross-connection facilities. And in our diagram, we’re using a vertical cross connection going from the first floor up to the second floor. Then we have our intermediate distribution frame, which will be sitting there inside the second-floor telecommunications closet. And that is the floor or the communications facility that is going to take care of that particular floor. And so if I have 100 floorbuilds, I might have 100 IDFs. Then I’m going to have backbone wiring that is going to go either horizontally or vertically throughout our networks.

We have those telecommunication closets where our patch panels, our switches, and our routers will reside. And we have horizontal wiring that goes out from the telecommunications closet and that intermediate distribution frame out to all of our work centres to those jacks that are in the walls. From there, we have patch panels that are going to connect those wires—those horizontal wires—back to a patch panel, which can then be pushed into those switches. And all of that sits inside that telecommunications closet. And then we have work areas. This is where your end user is going to be operating. And for them, it’s just a matter of taking their computer and plugging a patch cable from the computer to the wall jack. They never have to see the cable distribution system beyond the walls, but you as a network technician will. Now let’s talk about punchdown blocks for a minute. Punch-down blocks are going to be located in either your main distribution frame or your intermediate distribution frame.

These older blocks, the 66 block, were used for phones and the old Cat 3 networks. This has a lot of crosstalk issues, though, and so it’s not good for newer networks like Cat 5 and above. This is a bad choice for high-speed land, but a good choice if you’re still using some old Cat 3 networks. Now, most of the networks you’re going to come across are not going to be using a 66-block anymore. They’re going to be using a 110 block. Now notice up top that you see these metal teeth that are hanging there. And you can see that the cables from category three have been untwisted and punched down onto these blocks. And that’s why it’s called a “punch down block,” because you use a tool that literally comes and snaps the cable in between those teeth, and that’s going to hold it in place, making the network connection. We’ll talk specifically about punch-down tools in our Tools and Troubleshooting sections all the way at the end of this course. But for right now, I want you to remember that punch-down blocks, whether they’re 66 or 110, are going to be found in a main distribution frame or an intermediate distribution frame, and that you should be using 110 blocks for high-speed cat5 cabling because they have less crosstalk due to the spacing of those punch-down blocks.

Now, patch panels. On the back of these patch panels, you can see here on the bottom of the screen that there are punched-down blocks that look like a 110, but the patch panel on the front looks like a network jack. Now, why would I want to use a punt? Now why would I want to use a patch panel? Well, a patch panel is going to provide easy-to-use jacks on the front that can then be connected to the switch. And these patch panels are very cheap and inexpensive. For instance, if I was plugging and unplugging in the switch port all the time, I could damage that switch port, and that switch may be worth $2,000, $3,000, or $4,000. Well, this patch panel might cost me $10 or $20. And so if I’m going to damage one of these ports by plugging and unplugging things all the time, I want to do it on the patch panel. So the way this works is that on the back we have the punch-down block, the 110, and the wall jack is going to be connected to the back of this patch panel.

Now the front of this is where we will take a patch cable and go from port number one to port number one on the switch. And if I need to move that port to somewhere else, I’ll unplug it from port number one on the patch panel and plug it into port number two or three on the patch panel, which then makes the switch connectivity to those jacks go to a different place. So patch panels are highly recommended. Now, there are fibre patch panels as well. Just like we have copper ones, we have fibre ones, but like the copper ones, there’s no punch down. Instead, they’re going to use things like LC connectors, stick and twist connectors, or the Sts or the SCS. And the front is going to have patch cables that connect to different switch ports, like Mtrj on a switch to an AST connector on the front, and the back may be an SC connector going to a wall jack down the hall. The same concept as a standard patch panel, but with fibre in this case.

Now, what does all this look like when you put it together? Well, it looks like this. I have a workstation, and I connect my patch cable to a wall jack. The back of the wall jack is then punched down to a punch downblock in the intermediate distribution frame. From there, which is on the back of the patch panel, I have the front of the patch panel, which has an RJ 45 that can be connected to the switch, and the switch then connects over its connection down to the router, and out it goes. So all of these things are going to work together for a typical copper cable installation to give you lots of places where, if something breaks, I don’t have to run a single cable from the switch all the way through the wall back to the end user. I have all of these different cables. So, for example, if the one between the switch and the patch panel breaks, I just unplug it and replace it. If one between the punch-down block and the patch panel is broken, I replace that and just repunch it down. It gives me a lot of places to get the network up and running much more quickly than if I had to do an entire new cable run every time we had to move a machine or every time the machine cable got broken somewhere.