Specifications

B.1 The Dual Ring

FDDI Overview B–1

FDDI Overview

Fiber Distributed Data Interface (FDDI) is a set of ANSI/ISO standards for a 100

Mbps token passing ring which uses Multimode fiber, Single mode fiber, Unshielded

Twisted Pair, Screened/Shielded Twisted Pair or any combination of the four as the

transmission medium. This Appendix provides an overview of the applicable FDDI

standards that govern the use of FDDI network modules.

B.1 The Dual Ring

The most basic FDDI network is constructed of two independent rings and is com-

monly referred to as a dual ring (see Figure B–1). A dual ring connects to each FDDI

station in the network. Each ring can span a total distance of up to 100 km, which

allows for a distance of up to 200 km (2 x 100 Km/ring) of cabling. As many as 500

stations can be attached to the dual ring — typical configurations usually have no

more than 200 stations.

Figure B–1 FDDI Dual Ring

LKG-10095-96F

Dual Ring (200 km Total Distance)

FDDI Station FDDI Station FDDI Station