Using redundancy in FDDI networks

The connection management (CMT) of the fiber distributed data interface (FDDI) standard supports redundancy through a number of different network configurations. This redundancy may be used to increase the reliability of the network. These network configurations include using dual attachment stations in the dual ring, invoking the hold policy, using concentrator trees and using dual homing in the concentrator tree. The reliability of these configurations is examined and compared with network configurations without redundancy. The results show that the dual ring is able to withstand single faults, but not multiple faults. Other configuration options must be used to withstand multiple faults. The hold policy does not significantly increase the fault tolerance of FDDI. There are a number of useful configuration options in FDDI that allow redundancy. Depending upon the required level of robustness, FDDI configurations are available to meet the requirements