How to create a network using network cables

Getting Your Network Together (Network Cabling)

For anyone who has ever tried to connect their own network together, you know that it can be a little confusing to say the least. I still remember my first attempt at networking two computers together in my office; if time hasn't made the memory worse, it only took me three days to get it working. Granted, I didn't spend the whole day for those three days, when the frustration factor got high enough I took a break, but it was three days of messing with it, before my computers could actually talk to each other.

Now, I've got six computers on my little network and guess what? It's still a hassle getting everything together. Maybe I just don't have a network type of mind. Nevertheless, in the process of all this, I have actually learned a few things about networks and network cables.

Part of the confusion is that there's actually more than one type of cable available on the market and more than one way of connecting your network together. So, let's see if we can debunk a little bit of the confusion around these cables.

About the Wire

Your standard, run of the mill network cables are either CAT-5 (that means "category 5," not a fuzzy critter that purrs and says "meow"), CAT-5e or CAT-6. The difference between the three of these is in the specifications which created them. Essentially, as the numbers increase, the capacity of the cable increases as well.

Five Cats.jpg


In all three cases, the cables are made up of 4 twisted pairs of wires (that's 8 total wires). The great advantage of twisted pairs is that they are used to make a balanced line. In other words, there really isn't a "hot" and "ground" there are two different signal lines, neither of which is tied to ground. The difference in potential between them (the voltage difference) is what is read on the receiving end.

The other great advantage of twisted pair, at least as far as digital data transmissions are concerned is that they handle electrical interference better than straight wires. Because the twisted pair is alternating which wire is presenting itself more closely to the source of interference, the possibility that one line will receive all the interference (static) is negligible. At the same time, both wires won't receive the same
amount of interference at the same time. Since this is a digital signal, when it gets to the receiving device, that static will be eliminated by the first "gate" (a gate is a general term for digital electronics components) that the
signal passes through.

Okay so what does the difference between these three types of cables really mean to you as a computer user, trying to set up your network? Glad you asked. Take a look at this:

CAT 5 Unshielded Twisted Pair (UTP) is the most basic type of network cable. It is designed to handle either 10 or 100 Mbps (megatbits per second). For this reason the term 10/100 is often used to refer to this type of cable.


CAT 5 Screened Twisted Pair (SCTP) adds shielding to the UTP, for additional protection from electrical interference, especially when network lines are run near electrical lines or equipment. It is basically only used in Europe.


CAT 5e (Category 5, enhanced) cable increases the standards of data transmission to allow for Gigabit Ethernet; that's transmission speeds of 1000 Mbps. Most installations today use CAT 5e cable.

CAT 6 is the newest cable type in this series, providing the best performance, especially at high data speeds. With CAT 6 cable, there is a separator between each the four twisted pairs, reducing the possibility of crosstalk between channels and doubling the bandwith over CAT 5 cables. CAT 6 is capable of supporting 10 Gigabit Ethernet (10,000 Mbps).

Even though the cables are not forward compatible, meaning that you can't use a CAT 5 cable for an application that needs a CAT 6 cable, they are backwards compatible. So, if you have a CAT 6 cable, you can still connect it to equipment that is designed for CAT 5.

The modular connectors for both are essentially the same, at least from the user's viewpoint. They will both plug into the same jack on the back of your computer, hub or router. However, if you are building your own cables, don't try and use one for the other. The separator between the twisted pairs in a CAT 6 cable, makes it much larger in diameter. That means that it won't physically fit into the back end of at connector designed for CAT 5 cable, even though electrically they are the same.

Solid vs. Stranded Wire

Another important little detail about using network cables is the use of solid vs. stranded wire. Most CAT 5 and CAT 6 cables are made of 24 AWG (that's American wire gauge) solid copper wire. You can also buy it in
stranded wire. While I've always been a fan of stranded wire, because of its greater flexibility and resistance to breakage, I had to change my mind with CAT 5.

Due to the smaller diameter, or wire gauge of the individual strands in a CAT 5 or CAT 6 stranded cable, there is a higher level of attenuation. In other words, they lose more signal voltage. So, for less signal loss, especially over longer distances, solid cables are better. The basic rule of thumb is:

If it's a permanent installation, such as in the walls, use solid cable.

If it's going to get moved, such as from the wall to the computer, use stranded cable.

Peer-to-Peer or Host?

Although most networks are connected through some sort of host, it is possible to connect them peer-to-peer as well. What's the difference between the two? It's really rather simple:

A host network uses a central device, such as a hub, where everything else in the network connects to it.

A peer-to-peer network allows two computers, hubs or switchers to connect together, without any sort of a host controller between them.

A large part of the reason that we don't see too many peer-to-peer networks today is that almost everyone connects through a hub or switcher to access the Internet. However, if you have some reason to connect two computers together, without connecting them to the Internet, you could make a small network by just connecting those two computers, through their 10/100 network connector, using a special CAT 5 or CAT 6 cable.

The cable used for connecting the two devices together in this type of network is called a "crossover cable." The name derives from the fact that the wires aren't connected the same at both ends; instead, two of the pairs (green and orange) cross over each other, connecting to the opposite sets of pins. This allows the computers to communicate with each other, without any other device.

In the case of a LAN (local area network) or WAN (wide area network) that is running through a hub or switcher, this crossover function is accomplished inside the device, instead of in the cables.

So, what are Hubs, Switchers and Routers, Anyway?

Good question. All three of these devices are used for connecting computers together in a network. Both hubs and switchers can be used for connecting your local network and also for connecting that network to the
Internet; but they don't do so in the same way. Routers are used to connect more than one network together.

The basic difference between hubs and switchers is in the way that they work. When hubs receive "frames" of information, they send that same information out to all the devices connected to the hub. That means that
the bandwidth of the device and of the network must be divided between all the devices that are connected to it.

On the other hand, a switch keeps track of the MAC address (Media Access Control), which uniquely identifies each device on the network.
So, when a response comes back over the network, whether from the Internet or another device on the LAN, the switch is able to send that information directly to the device that requested it, instead of having to "broadcast" it to
everyone. This allows for faster communication, as each of the ports can have access to the complete bandwidth.

Routers are completely different devices. They are used to connect various networks together. Unless you are a network specialist (which means you probably wouldn't be reading this), you will probably never touch a
router in your life. However, every bit of information that you transmit farther than your LAN, ends up going through one or several routers.

Optical Connections and Networks

There is another type of network "cable" that we need to mention here, even though it isn't a cable; that is with fiber optics. There are a number of advantages of using fiber optics for data transmission, first and foremost of them being that the light traveling down those fibers isn't subject to electrical noise and interference. Nor do they have a crosstalk problem.

To use fiber optics for a network connection requires a Media Converter, which changes the electrical digital signal to an optical signal (light). At the other end, the Media Converter changes the signal back to an electrical one, so that your computer can read and use the data.

For more information about Media Converters and using Fiber Optics for data transmission, check out our article "Getting Fiber Optics & Wire to Talk to Each Other with Media
Converters
."


 

Rich Murphy