Download Cabletron Systems EPIM F3 Specifications

Chapter 5
FDDI RING TOPOLOGY
This chapter describes FDDI ring topologies as well as FDDI design
considerations that may be useful to a network designer.
DUAL RING WITHOUT TREES
The Dual Ring Without Trees configuration consists of dual attachment stations
that form a ring by connecting A ports to B ports and B ports A ports. This
configuration is commonly used in small engineering/research environments to
localize FDDI rings. The disadvantage of the Dual Ring Without Trees
configuration is the risk of a wrap condition in the event of a station failure.
Optical bypass switches are typically used in this configuration to prevent a wrap
condition. Figure 5-1 shows a Dual Ring Without Trees configuration.
PRIMARY RING
DUAL ATTACHED
STATION
SECONDARY RING
FDDI DUAL
COUNTER-ROTATING RING
NETWORK
DUAL ATTACHED
STATION
Figure 5-1. FDDI Dual Ring Topology
5-1