Cable Management

Cabling a Small Office

We covered a ton about different communications and media types and how it communicates. Let's get into the physical side of this. What does this look like in reality?

The scenario is that I've been hired to go into this small workspace, and I need to create a design to cable this up. First of all, I'm going to take a look at it, and I'm going to assume that I'm going to want an access point at each one of these locations. So somehow I need to get from the switch to those access points.

I also see workstations here. I see several workstations here, and I see some places that possibly is going to be a workstation. It doesn't have a computer at it, but I'm going to think that that's probably something I'm going to need in there as well.

I see that there's a little kitchenette here, a place where employees might go and prepare meals and stuff, and probably don't need that in there. But we're seeing more and more Internet of Things devices out there that need some sort of network connectivity. A lot of them connect wirelessly. I'm just going to put a few cable drops in there. When I say drops, that means that I'm going to actually put a jack in there that people can connect into. So I'm going to put a few in there.

And for each one of these desks, I'm actually going to do more than one cable drop for those desks, so there's going to be more than one jack available for each of those desks. One I might have the connectivity to the phone. I might have the computer. They might have a NAS. They might have a printer. There might be multiple reasons why they have lots of devices that they need to connect. And so what I'm going to do is I'm going to put three drops for every one of these stations. That's three jacks for every one of these stations that I have.

The Point of Demarcation and the Network Room

Another thing I'm going to need to provide this office is an internet connection. So I'm going to call up an internet service provider and order an internet connection, and they're going to tell me exactly where it is that their equipment is going to be at and where I can connect into their equipment. That's called a point of demarcation, or demarcation point. They probably already have a room set aside specifically for that. Maybe it's in this room right here, and there's going to be a jack, or there's going to be a coax termination point, or something in there that is going to be the point of demarcation. Anything before the point of demarcation is the responsibility of the internet service provider. Anything after that is my responsibility.

So I've got the demarcation point. I'm going to make this room right here my network room. So that's my network room, or network closet. A lot of times it's called a closet because in some older buildings networking was an afterthought, and so a lot of times the network got stuck in a closet. And I've certainly had cases where I was stuck in a closet configuring equipment and stuff, because it just was not thought of in some of these older buildings.

In here I'm going to put maybe a modem, maybe a router, a firewall, a switch. I'm going to put some equipment in there, so I'm going to need a rack. I'm going to put a rack inside there that I'm going to put my equipment on.

Running the Cable

Then I need to somehow get from this switch to my workstations, and I need to put the drops into these workstations. So I'm going to create a cable run, and it's going to go from this rack out, and I'm going to have three cables that are going to drop at this workstation right here. And then I'm going to have another three cables that are going to come to this workstation right here. And another three cables are going to come to this workstation right here. And another three cables to this workstation right here. So now, already, just for one room that has four desks, I've already run 12 cables here. Quite a bit.

Now remember, it's better for me to run a cable now rather than later on. If I have to call somebody back because I under-scoped this, or I didn't run enough cables to these devices, and I have to call somebody back — a low voltage contractor to actually install another line — it's going to be quite a bit more costly. So I'd rather just get extra lines out there now than worry about it later on.

So then I'm going to run three cables to this drop right here. Another three cables to this drop. I'm going to run a cable to each one of my access points that are out here. Another three cables to this drop right here. Maybe three cables to my kitchenette there. So you get the point that I'm going to run all my cables from this single location, and I'm going to what's called home run this all out to these different devices, and they're all going to come into this rack right here on the end here.

What I'll probably do is I'll have jacks that are in the wall. There's these little jacks that you punch down and you plug them into the wall. So I'll put those all into the wall so that way these devices can connect. So the jack might be right here. The plate where the jack is at might be right here. And then they're going to need to have a cable that goes up to their desk. And so they have a cable that runs up to their desk.

One thing I do have to keep in mind, and I'll mention this later as well, is that I only have 100 meters to work with. And because I have a cable that runs from this jack to that laptop right there, maybe that's 10 meters in itself. Or maybe it's probably not 10 meters, but possibly I've run 30 foot cables from a jack to a machine before. Or maybe — the other thing too is I'm going to actually have a little patch cable in this room as well. So I've got to be conscious of that. And so the general rule is that from your network closet to all of your devices, you don't want to run a cable that's longer than 90 meters. 100 meters is the max for Ethernet. So if I ran 90 meters, that gives me 10 meters for a patch cable on this side to connect to the device and a patch cable on this side to connect into the switch. But just know that I probably want to limit these cable runs to 90 meters.

And then on this side of it, I have jacks on this side. I'm actually going to put a jack over here on this side, and I'm going to show you why that is. But now I've got connectivity within the office, and I'm ready to connect it into my devices.

Inside a Network Room

This is a traditional, typical network room or network closet. This is, I think, probably a network closet. This is an old building, so probably was a closet at one point in time. We outfitted it and made it into a network room. And so this is one of the networks that I worked on in the past.

Off here in the background we see the demarcation point. So the phone company provides a line up to a certain point, and this happens to be Ethernet over fiber. So then they had equipment that converted it to copper. So this is a copper connection right here, and I've got an Ethernet cable plugged into it.

And then I've got my rack right here that's setting up. And racks are measured in U's, or units. And so this is probably — my guess would be — like a 44U rack. So it has 44 units in it. And then you buy equipment and it takes up a certain amount of Us. So, like, my switches right here take up one U on this rack. So I can actually have 44 of those different switches on this rack.

Up at the top is my patch panel. I talked about those network runs that come from the rack and go to each one of those drops that I have out on my network. And so this is showing the patch panel of where all those network connections come back in and they get punched down. There's a tool that actually punches it and pushes the little conductors into these little slots on the back. They connect onto the back here. And then on the front I can plug in using an RJ45.

And so I buy patch cables. I don't make patch cables. I've seen a lot of lousy patch cables and it takes up a lot of time. So for a lot of businesses, I'd say it's better just to buy patch cables. But there are patch cables that are running from each one of these drops down this cable run right here and then up into these switches. And so I've got a lot of these that are running down here. You can see there's a big mass of connections.

And in here are a bunch of access switches. So I've got the switches that the devices are plugging into. So those are access switches right there. And then they're being covered up by some patch cable management. So they run through these little troughs. This is a little trough right here as well. So they run through these troughs to clean it up. So what I'll do is, there's little locks on here and I will unlock that and then run the cable down, and these will pop down and I'll run cables through here, down here, up here, through these cable runs and up to the switch to have it all connected in. And so those are the cable runs.

And I don't necessarily want every single jack live out there. So once again, those desks had three drops for every desk. And so if I had each one of those live, I would have to have more switches. So maybe I don't want to make every single one of those live. So at different times, I'll come in here and clean this up and clear up a bunch of ports on the switches, and then run only the ones that I need to, to make the ports live that need to be live in this case right here.

So I have the access switches. Those are what is connecting all of the different devices out on this network, and they are connecting them to the network. It gives them connectivity. And then down here towards the bottom, this is a spare switch right here. And then this switch right here and this switch right here are my core switches. You can't see one of them, but those are my core switches. So everything comes from those access switches and from other switches in the building. So this is a big enough location where there's other closets. There's other network closets throughout this building, and so they come back here as well. And so they all connect into these core switches.

Now, no fiber in these runs, but a lot of times you'll see that fiber runs from these main core switches out to your access switches. So a lot of times you'll see fiber runs that go between these.

And then if you look further down on here, there's a little device that sits on here. It's quite a bit smaller, and that's the wireless LAN controller. So that controls all of the access points. And then down below that is the firewalls. So those are the firewalls. There's two of them. They're in redundancy. They're plugged into these switches, so there's redundancy in there. And then down below that we have the UPSs — uninterruptible power supplies. So these UPSs supply power. So if there is ever a power outage, then we'd still be up and running. And that's important because we have voice over IP phones and we need those phones up and running even in an emergency.

So how this would look if you were to trace this from our devices out on the network: it would be connected from that device down into the jack. The jack would then run to this patch panel, and maybe this jack right here. And then from there, we have a patch cable that runs down and into the access switches. And the access switches have lines that come down — more than one — that come down into both of these cores. And so we've got two core switches for redundancy. From there, things are guarded. They come down and are guarded by these two firewalls. And these firewalls then go out. They actually run up and around and come back down and plug into the point of demarcation. So that's how those are connected.

I am going to point out one other thing here too. I've got some 110 blocks here in the back. 110 blocks are old phone system connectors. You can see that those are all taken out. I cleaned all of these up. But the phone company would come in and that would be the point of demarcation for those phone lines, and then you would create little jumpers that would go and connect your different phones. Thank goodness with a lot of these networks you don't have to do that anymore. Some bigger businesses would have to have just a person dedicated to phones, and now it's all voice over IP. You just plug the phone in and it works. Or now what I've switched my company over to is it's just all soft phones. So they're all on your computer and you just use your computer. So we've come a long ways. But this is a network closet here, and how it connects from these different devices from your switch out to your laptops and your desktops and your wireless access points and all of the other things that you're networking.

Bigger Buildings and Multiple Closets

So if you're working in a big office building and you have lots of connections, then it might not be reasonable to come back to just a single network closet. In that case, you might have multiple network closets. And in this case, we said that there's a rack in here and we have switches on that rack. And if we are going to some of these connections and they're over 90 meters, then we run into that issue where we're going to possibly go over the 100 meter limit with Ethernet, and we're going to maybe get some strange network connectivity issues. So we want to avoid doing that.

So let's say we have another closet. Let's say there's another closet over here and we need to connect some of these devices to that. So we're going to have a rack in there with some switches on it. And then between these two devices, we're going to either run some fiber lines or some Ethernet cables between these two devices. We need to maybe run multiple. If they're Ethernet, maybe we're going to make a port channel and run multiple lines and group them all together so it acts as one. So we get a 4 gig connection instead of a one gig connection. Or maybe our switches are capable of handling a 10 gig connection. So we want to run some sort of connections between these. And if it's long enough, these connections may need to be fiber.

And then for all the close ones to this network room, then we'd run cables out to the different drops. And for the ones that are closer to this one, then we run connections out. And we would have a patch panel and a switch in there that would service all the ones that are closer to there. And then we would have a patch panel and switches that would service all the ones that are closer to that. So that's what you would do with a bigger office.

Now there's names for these. So we call this a main distribution frame, or MDF. So these closets are often called MDFs. And I think that actually stems more from the phone industry, where we call this the MDF.