PCI FDDI Administrator's Guide

PCI FDDI
Topology
Chapter 128
Figure 1-4
Dual Ring of Trees Topology
The dual ring of trees is the most flexible and the most recommended
topology. It provides a high degree of fault tolerance. Concentrators form
tree branches that can be extended as long as the station number or ring
distance limits are not exceeded. Station removal or change can be easily
done without causing disruption to the LAN.