So it's no wonder most enterprises try to avoid upgrading their wiring more than about once every 10 years. And when they do get around to it, most organizations install cable that meets the latest EIA/TIA standard, to ensure maximum longevity.

And the Category Is ...

Over the past seven years, deciding which standard to buy into has been a no-brainer. Since 1995, companies looking to rewire opted for the EIA/TIA Category 5 standard, despite the hassle and the expense of it, because it meant they'd be able to run 100-Mbps Ethernet. A year later, the IEEE started developing the gigabit over copper standard for use with Cat5 cable, which was an even bigger incentive. The Cat5e standard tweaked the spec to ensure that gigabit would work. It will take many years for most desktop applications to grow into gigabit speeds, but it really is just a matter of time.

In June, the EIA/TIA finalized the Cat6 standard, which, theoretically, makes it possible to send bits faster than Cat5e does, so Cat6 is the obvious choice if you're rewiring, right? Wrong. You'll pay up to 50 percent more for Cat6 than you will for Cat5e, despite the fact that Cat6 provides no known benefits--no existing or planned standard, not even the next version of Ethernet, takes advantage of Cat6. The IEEE's 10 Gigabit standard (802.3ae), also approved in June, runs only on fiber--there are no plans to run it on twisted pair.

The best argument that cable vendors can come up with is "more headroom," but what they really mean is "more profit." A good Cat5e installation, and even many Cat5 installations, can provide more than enough headroom to run gigabit in most situations, and a simple certification test will tell you if your cabling infrastructure is up to spec.

Some vendors have talked about developing cheaper gigabit interfaces, which is possible, at least theoretically, with Cat6, but it's hard to imagine how they could come up with anything that could compete with the increasing volumes that continue to drive down the price of the existing gigabit interface technology.

Sure, a lot can happen in 10 years. Maybe Cat6 is a worthwhile investment, but for now, it's nothing more than an expensive insurance policy that your cable infrastructure will support some unforeseen technology that may emerge in the next decade or so. Cat6 is backward-compatible with Cat5e, though, so you could just run Cat6 cable now, and upgrade the terminations later, thereby minimizing cost and risk. But you better make sure it will work. Even mixing vendor equipment with a straight, standard Cat6 install is risky this early in the game.

Only you can determine how much insurance you need. Whatever you decide, though, calculate carefully. And hire a professional to do the job.