Copper has had a long life for data networking connections, but an all-optical data center is likely to be in the cards somewhere in the future. And it's going to be glass, despite the temptation of other shiny toys like RF and LEDs.
Don't get me wrong, I love copper wiring. With a little silicon magic, very good cable, and decent crimping, you can get 10 GigE connections for short runs without a lot of headaches. At longer distances, DSP processing and clever algorithms is squeezing out more speed from existing copper plant For people who already have copper in place and some certainty with cable quality, copper is great.
But if you want to go past 10 Gbps without having to recable down the road, fiber is the way to go. Optical fiber today is capable of supporting speeds of 100 GigE on multiple wavelengths and has a future path to 400 GigE and Terabit Ethernet (1TbE) speeds. Invest in fiber today and you are effectively future-proofed for network speed increases without having to worry about pulling it on the (inevitable) day when you have to put in optical for higher-speed connectivity within the data center and between it and the rest of the world.
Over the past twelve months I've seen a couple of new wave ideas for high-speed networking within the confines of the data center, but both are based on line-of-sight schemes. Basic off-the-shelf LEDs are being used by the Fraunhofer Heinrich Hertz Institute to create high-speed , no-wire data connections. Initial experiments demonstrated rates of up to 800 Mbps and up to 500 Mbps at a system exhibited at trade shows. More recent work has demonstrated rates of 1 Gbps for single light frequency, adding up to 3 Gbps when using three different color LEDs. Given the relative infancy of GigLED, I wouldn't be surprised to see speeds of up to 10 Gbps with some tinkering.
Short range RF wireless networking is also a potential option for the future. Low-power radios using the 60 GHz radio frequency are being rolled into "stock" 802.11 a/b/g/n WiFi chips to provide up to GigE speeds for moving around HD video and other data types between storage, PCs, tablets, and big screens. Next-generation devices built around the unlicensed 60 GHz band offer the potential for transmission speeds close to 11 Gbps at lower power.
Current applications for 60 GHz are focusing around PC-esque "personal network" applications to get rid of cables for docking stations but Intel researchers are looking at 60 GHz to provide an evolutionary step beyond vanilla Wi-Fi in 2.4 GHz and 5 GHz bands, boosting data rates to 1 to 2 Gbps.
However, both GigLED and 60 GHz share some of the disadvantages as well as advantages. Both technologies are effectively "same room." LEDs require line-of-sight between transmission nodes -- something researchers think would work wonderfully with light bulbs (It does, however, redefine the term "lights out" data center).
The 60 GHz band is almost as "limited" as LEDs, requiring nodes to effectively be in the same room and able to bounce signals off the floor or ceiling. With 60 GHz, you don't need pure line-of-sight, but you're not going to be able to be in the next room without some sort of relay or repeater.
Both GigLED and 60 GHz are still in their earliest days of implementation. I expect some experimentation with 60 GHz for in-room data center networking in the years to come, while GigLED will get some more polishing before it shows up as something more than a neat science project.
If you want to play the "green" card, glass is cleaner and potentially safer than copper. Animals like to chew on phone lines. The price of copper has lead to unsavory types cutting and stripping cables out of exposed physical plant -- power and data -- for a quick trip to a recycling center. Glass doesn't have that allure because it's cheap and easy to recycle.
Speaking of connecting your data center to the rest of the world, service providers would prefer you to be on fiber. Fiber means you can get bandwidth via a simple optical Ethernet handoff, rather than having to wrestle with copper and all the (aging) bits and pieces necessary to go from optical to copper to deliver bandwidth speeds under 100 Mbps.
And the faster you want your broadband connection, the more you really need fiber for your and the service provider's sanity. Independents can provision service of up to 100 Mbps over copper with pair bonding and clean wires over short distances, but they want you on their fiber network because they don't have to pay the incumbent copper-owners every month for those pairs. Meanwhile, the incumbent wants you off the copper because of all the legacy gear it doesn't want to maintain.
If you want a moral to this story, it is: Think glass. Migrating to fiber and slowly moving away from copper will ultimately reduce your headaches and should save you some money in the long run.