Copper cabling at the crossroads

Most companies like to think of their cabling systems as plumbing, a fixed quantity that is altered only at substantial expense. Smart shops always try to future-proof themselves, but what’s in the cards for cabling?

For the last five years or so, Category 5 UTP cable has been the default choice for most enterprises, thanks to its capability of supporting 10Mbps and 100Mbps networks. Furthermore, in the last 18 months, more and more vendors have begun to deliver devices that support gigabit speeds using good old Category 5 cable. Do these new offerings represent new life for copper networks, or do they just provide proof that the future belongs to fibre, as copper’s physical characteristics guarantee the failure of 10Gbps and faster copper networks?

The answer to this two-sided question is “Yes.” Many businesses will indeed choose to take advantage of running gigabit technologies on copper, whereas others will read the handwriting on the wall and start converting to fibre networking.

But still others will do neither. Although gigabit speeds are appropriate in some situations, few enterprises will undertake a wholesale conversion for years to come because most don’t require such a fast connection to internal networks. The trick is determining when and where it’s appropriate to deploy copper-based gigabit networks and when you’re better off upgrading to fibre.

Copper-toned facts

The first step in deciding the future of your network is to recognize the inherent limitations of copper. You can crank Ethernet on Category 5 cable from 10Mbps to 100Mbps – and recently to gigabit speeds – by manipulating transmission characteristics. But those strategies fail when you try to run a 10Gbps network.

It’s all about the math: Even Category 7 UTP wire won’t cut the mustard for 10Gbps networks, because it supports only four times the bandwidth of Category 5 wire. Distance is another problem: gigabit Ethernet on Category 5 cable is limited to a distance of 330 feet, whereas the most common fibre type – 62.5-micron multimode – extends the network’s reach to 900 feet. You can even span distances up to 3.1 miles using 1,000Base-LX on 8-to 10-micron single-mode fibre.

Although older technologies such as standard 10Mbps and 100Mbps Fast Ethernet are more forgiving, achieving gigabit performance with copper requires exacting attention to detail and Category 5 certification for every part in the link. A bargain-basement adapter, a hastily substituted cable, or a corner-cutting installer will handicap your gigabit-speed network.

As recently as two or three years ago, copper’s fans could play the value card. At the time, the common wisdom was that fibre was expensive, fragile, and tricky to install. But improvements in characteristics such as its tensile strength have made it easier to pull fibre cables around corners and then terminate them.

Moreover, product families such as 3M’s Volition line allow installers to set up fibre networks faster than those working with copper cabling. Most copper Ethernets use only two of the cable’s four pairs, but fibre networks are built on single pairs of optical fibre.

In addition, optical hardware is becoming less expensive. On a per-port basis, the prices of routers and switches are approaching parity with that of copper gear. Of course, most shops thinking about moving to fibre don’t have to completely rip out their existing infrastructure; most applications and users are perfectly happy with Fast Ethernet, and simple applications such as Web browsing and sending e-mail require only a switched 10Base-T network. Future servers will come with enhanced I/O technologies such as InfiniBand and PCI-X that can pump data into the network at gigabit speeds and faster.

Where copper fits

Where are shops going to deploy gigabit (and faster) speeds? The most obvious choice for gigabit deployment is a network backbone, if it hasn’t been done already. Gigabit technologies are highly appropriate for the server room, and if you’re concerned that existing patch panels and other wiring system components aren’t up to snuff, connections in the server room are the first ones you should replace anyway.

Some user desktops may also be natural choices. Any user pushing large masses of data to the network is a candidate for a gigabit connection.

What about copper? If your cable runs aren’t too long, you’re not expecting to use the cable plant for more than a couple of years, and your installation is done competently, you can probably expect to get several more years out of a copper network. Otherwise, it’s time to start thinking about fibre.

If you want your cabling system to support ever-increasing network speeds and still be top-notch five years out, switching to fibre is your only choice. Copper also presents a security risk: All that wire makes a great radio antenna for your network traffic, and it doesn’t take a secret agent to intercept the data, just some fairly simple equipment. Fibre networks can’t be tapped this way because photons don’t generate radio frequency emissions.

Of course, none of this means that copper is going away anytime soon. So much is already installed, and people are comfortable with a familiar technology. Besides, both copper and fibre gigabit implementations come at a premium. Today, desktop computers come standard with 10/100Base-T connections, so businesses have little incentive to substitute anything faster – that is unless your applications demand it or the street price for faster network interface cards drops below US$10.

For all the talk of how rapidly the computer industry changes, some transformations happen less rapidly than others. Physical connections are one area in which change happens at glacial speed. For years, pundits have seen fibre-optic networking as a technology of the future. The future is finally starting to happen. Brilliant engineering has stretched the capabilities of copper networks beyond what was thought possible even three years ago, but it’s clear that it’s downhill from here for copper networks.

Although it may be years before fibre pulls ahead of copper as a desktop technology, it’s clear that, for all but temporary installations, fibre is the first choice for backbones, servers, and data-intensive applications. The capability of running gigabit-speed networks on copper is great, but in the end, fibre will dominate networks.