Connections +
Feature

Spares, Strikes and Misses

Columnist muses on some of the fearless technology predictions from the board that didn't quite cut it.


July 1, 2007  


Print this page

With CNS approaching its 10th anniversary of publication, myself and a group of editorial advisory board members who have been with the magazine since Day One, recently reminisced about the causes championed in this space that have simply not delivered on the promise.

For example, Asynchronous Transfer Mode did not become the dominant LAN protocol. Wireless has not replaced structured cabling in new commercial buildings.

And, as my fellow board members pointed out at our last meeting, my fearless prediction (made not once, but twice) that fiber to the desk would one day soon take over from copper cabling is now cowering behind stacks of unsold reels of two-strand fiber cable.

But, as happens periodically (but always triumphantly, of course) in my career as a sales manager, I have seen an opportunity to snatch victory from the jaws of defeat.

For example, it may not have arrived at the desk, but fiber certainly is making its presence felt in between the Ethernet switch and the multiple endpoints in today’s data centre.

Data centres today have moved beyond the simple interconnection of servers and switches. They are not so much a “computer room” as a “strategic corporate asset,” critical to the operation of the owner’s business.

The network infrastructure must, therefore, be robust and versatile enough to support 24/7 availability and monitoring, “5 nines” reliability, redundancy, security, and rapid deployment / rearrangement.

High bandwidth

International standards bodies are hard at work formulating recommendations for preferred high performance cabling infrastructures in both copper and fiber media.

Data centre environments lend themselves to fiber optic cabling as the main media of choice for large parts of the DC, including the Storage Area Network (SAN), mainframe, switch and tape/disk drive connectivity.

The advantages of a fiber infrastructure are compelling. Fiber delivers high bandwidth and covers a broad application spectrum.

It is a native media in virtually all data and high-speed storage applications with products available from a wide range of vendors. Applications such as 100BASE-FX, FDDI, 1000BASE-X, and 10GBASE-X (more on the “X” in 10GBASE-X later) all have standard fiber interfaces. Fiber is also a standard media for Fiber Channel, Serial HIPPI, and IBM’s ESCON.

Fiber offers the capability of enhanced administration in the data centre. Its low loss means that multiple cross-connect administration points can be engineered without fear of surpassing the power budget constraints of high-speed applications.

Fiber’s large operating performance margins, immunity from electromagnetic interference and power surges, and robust cable design give fiber network’s increased reliability, making fiber the right choice for mission-critical areas of the data centre.

All of the above is fairly intuitive. We have heard for years about fiber’s inherent benefits over copper. But is the choice to deploy fiber in the data center really this simple?

With the advent of 10 Gigabit Ethernet, the answer is a resounding, “of course not!”

There are a number of 10 Gigabit media options available for fiber today, including:

10GBASE-SR. A low cost optical solution employing 850 nm Vertical Cavity Surface Emitting Lasers (VCSEL’s) and multimode fiber (ideally laser-optimized OM3 to support distance up to 300 m)

10GBASE-LR. A 1310 nm wavelength solution running up to 10 km on singlemode fiber

10GBASE-ER. A 1550 nm wavelength solution running up to 40 km on singlemode fiber

10GBASE-LX4. Uses 4 different wavelengths of light, each running at 2.5Gbit/sec. on the same FDDI grade (62.5 micron) fiber strand. Designed to make use of the installed base of FDDI fiber, it requires 4X the optical components of 10GBASE-SR, plus a specialized multiplexer, which makes it pricey!

10GBASE-CX4. A very low cost protocol for interconnection of switches in a closet or DC, but with limited distance support; about 15 meters.

10GBASE-LRM. Published in September of 2006 as IEEE802.3aq, this option employs Electronic Dispersion Compensation technology with long-wavelength optics on multimode fiber.

And, finally, as an extension to 10GBASE-LRM, vendors like HP are working with the IEEE on 10GBASE-LRM/LR, which will employ the high quality laser from 10G-BASE-LR, and the EDC signal processing technology from 10GBASE-LRM.

The goal is to leverage the volume of 10GBASE-SR, -LX4, -LR, and -LRM into one single standard that would support all three of singlemode (20 km), FDDI-grade multimode (220 m) and laser-optimized multimode while driving the cost of optics down to well below current levels.

And if that happens, there will be no stopping fiber to the server cabinet, or even to the desk, for that matter. Third time lucky, perhaps?

Bob Kostash is the Sales Director of CommScope Solutions Canada Inc. and a member of the magazine’s editorial advisory board. He can be reached at bkostash@commscope.com.