HP ProCurve Tech Brief: 100BASE-FX Ethernet

In large campus environments, fiberoptic cabling is required to reach the distances between

buildings. Because of the FDDI legacy, many of those fiberoptic links are constructed of

multimode fiber with distances no greater than two kilometers. When 100-Megabit

communication is adequate, this campus example is a perfect fit for 100-FX.

Department stores and grocery chains are other examples where 100-Megabit communication is

adequate, but the challenges are long distances from the computer room to the point-of-sale

devices and cash registers. Again, 100-FX is ideal for such a network.

Military and other high-security networks often standardize on fiberoptic networking because of

its inherent security: signals do not "leak" from the cables, and the cables are very difficult to

tap without being detected.

Finally, cost is a big benefit of 100-FX, because 100-FX typically uses LEDs instead of higher-

cost lasers. With less expensive transceivers at each end of the link, the overall system cost is

lower. Existing multimode fiber segments further reduce the cost by allowing customers to re-

use that fiber instead of installing new fiber.

Conclusion

Even 10 years after its creation, 100-FX is a viable technology with compelling reasons for its

use. There are many situations where existing multimode fiber is available, and that fiber can

be used to extend the network with 100-FX links. Also, the long range of 100-FX allows

connectivity over multimode fiber where Gigabit does not reach. Some proprietary equipment is

designed for 100-FX, and those legacy solutions are still in use today. And military installations

that prefer fiberoptic connectivity for security reasons still benefit from the long distances 100-

FX supports over multimode fiberoptic cabling.

For reasons of low cost components, ability to re-use existing multimode fiber and support for

long distances, 100-FX will be in use for many years to come — and ProCurve will continue to

support this proven technology even as we bring new switches to market.