Following on from my recent blog on fibre cabling, this blog will assess why we still use copper wires.
Quite simply, the answer is, copper still does the job.
Back in the early 90s when many of us were discovering the joys of pubs, clubs and doner kebabs, Category 3 unshielded twisted pair data cabling was born, delivering an impressive 10 Mbit/s.
Back then companies were running US Robotics 14.4k modems to communicate with the outside world, so 10 Mbit/s was surely all the speed we would ever need.
A few years later Category 4 cabling threw its hat into the (token) ring, promising speeds of 16 Mbit/s operating at 20 MHz. Unfortunately everyone had bought 10 Mbit/s hubs. Some high flyers even bought 10 Mbit/s switches.
For those of you that don’t remember hubs, what’s the difference? In a word, intelligence.
Hubs and switches, are both devices that let you connect one or more computers to other computers, networked devices, or even other networks. Each has two or more connectors called ports, into which you plug the cables to make the connection.
Varying degrees of magic happen inside the device, and therein lies the difference. I often see the terms misused, so let’s clarify what each really means.
A hub is typically the least expensive, least intelligent, and least complicated of the three. Its job is very simple – anything that comes in one port is sent out to others.
If a message comes in for computer “A”, that message is sent out all the other ports, regardless which port computer “A” is on.
And when computer “A” responds, its response goes out to every other port on the hub.
Every computer connected to the hub “sees” everything that every other computer on the hub sees. The computers themselves decide if they are the intended recipient of the message.
The hub itself is blissfully ignorant of the data being transmitted. For years, simple hubs have been a quick and easy way to connect computers in small networks.
A switch does essentially what a hub does, but more efficiently. By paying attention to the traffic, it can “learn” where particular addresses are.
Initially, a switch knows nothing and simply sends on incoming messages to all ports.
However, the switch has learned something – it knows which connection the sender of the message is located. Thus, when machine “A” responds to the message, the switch only need to send that message out to the one connection.
In addition to sending the response through to the originator, the switch has now learned something else – it knows on which connection machine “A” is located.
Subsequent messages destined for machine “A” need now only be sent to that one port.
Switches learn the location of the devices that they are connected to almost instantaneously. The net result is that most network traffic goes only where it’s needed, rather than to every port.
On busy networks, this can make the network significantly faster.
Category 4 cabling disappeared quicker than it arrived, making way for the game changer, Category 5 cabling. More commonly known as Cat5 , it offers speeds up to 1000 Mbit/s, with a performance of up to 100 MHz.
Cat5 was introduced to us in the late 1990’s, and was surely all we could ever need in a cable, however, in some applications it encountered crosstalk problems.
To overcome this Cat5 was enhanced, giving us Cat5e – it is said that most manufactures tested their brand of Cat5 cable to Cat5e standards and passed it, so simply added an “E” to their packaging.
Cat5e exploded into the market place, quickly replacing all old thin net (BNC) and Category 3 networks. It was most commonly used to deliver 100 Mbit/s to the desktop, and even running analogue and digital telephone systems through its cores.
Cat5e is still used in approximately 70% of our installs. It runs 1000 Mbit/s to the desktop up to physical lengths of 90 meters plus. It can handle all PoE requirements, carries video signals and can even be used as control wire in door entry systems.
As soon as just about every company in the world had a nice, fast and efficient Cat5e network, Category 6 cabling, or Cat6 if you prefer, made its way into the networking scene, offering us all the benefits of Cat5e with the added bandwidth performance of up to 250 MHz, and even 10 Gbit/s up to 27 meters - as long as you don’t bend it, touch it or even look at it in a funny way.
Regarded by many IT and network managers as “pointless”, Cat6 cabling did not force Cat5e into early retirement as most expected.
It wasn’t helped by being more expensive than Cat5e, taking longer to install and not being able to use standard dado trunking systems as the bend radii on the corners forced the cable to fail when tested.
We commonly only install Cat6 cabling in new builds, with compatible trunking systems and larger budgets.
- 20 years ago - 10 Mbit/s was all the speed we could ever need.
- 10 years ago - 100 Mbit/s was starting to look slow.
- 5 years ago – if you didn’t have 1 Gbit/s to your desktop, people laughed.
There are many things that can be augmented for the greater good. In the world of cabling Cat6 got the treatment, giving us Cat6A.
Mainly used in Data Centres it offers 10 Gbit/s with a performance of up to 500 MHz running lengths of up to 90 meters.
If you’re thinking of upgrading you’re current network to meet future requirement, Cat6A shouldn’t be dismissed as “too expensive” and “pointless”.
In my opinion it’s the only way to go.