Gigabit Ethernet Technology And Fddi Technology - Allied Telesyn AT-EX1001SC/GM1 Guia De Instalacion

Gigabit Ethernet Technology and FDDI Technology

Because of its high-speed and fault-tolerant features, fiber distributed data
interface (FDDI) has frequently been used to build backbone networks.
However, the growth of new applications that require extremely high rates of
throughput, greater than that allowed by FDDI, have emerged and have
exceeded the capabilities of FDDI to handle the load. Examples of high demand
network applications include streaming audio and video content.
The solution for many networks is to migrate from FDDI to Gigabit Ethernet,
which offers the same resiliency as FDDI but with greater bandwidth
capability. However, one of the principal disadvantages to migrating from
FDDI to Gigabit Ethernet has been the cost of replacing the legacy multimode
fiber optic cabling of the FDDI topology to one designed for Gigabit Ethernet,
typically single-mode fiber. Currently, Gigabit Ethernet transmission on
multimode fiber is limited to a maximum of 550 meters (1500 feet) on 50/125
micron fiber and 275 meters (754 feet) on 62.5/125 micron. In network
configurations requiring greater distances, a network administrator has been
confronted with the choice of either retaining FDDI and its lower bandwidth or
replacing the existing multimode fiber cable with single-mode cable, typically
at great cost.
The AT-EX1001SC/GM1 Gigabit Ethernet Multimode Extender greatly
simplifies the migration by allowing the network administrator to install
Gigabit Ethernet while maintaining the existing multimode fiber cable. With
this unit, which must be used in pairs, the network administrator can extend
the distance of Gigabit Ethernet transmission over multimode fiber cable from
the current limitation of 550 meters (1500 feet) to 2 kilometers (1.24 miles). In
many situations, this eliminates the need of replacing the existing multimode
fiber cable by enabling the network administrator to use the legacy cable
system.
Figure 2 illustrates a network that incorporates two AT-EX1001SC/GM1
Gigabit Multimode Extenders. The units interconnect an AT-8224XL Fast
Ethernet Switch with an AT-A15/SX Expansion Module and an AT-9006
Gigabit Ethernet Switch.
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