Redundancy – Avoid Single Points of Failure
Media redundancy is primarily used to avoid single points of failure in industrial communications networks. Wherever there is a single point of failure it is possible for the communications network, for instance in an automated production line, to be completely disabled by a single technical fault. The consequences of such a failure can potentially be extremely costly. If redundant structures are used then a single failure merely causes the network to fallback to a degraded state. Communications via the network remain viable, and the redundant system makes it possible for a repair to be carried out to restore the previous fault-free state. Redundant network structures are used for two separate purposes: load balancing & fault tolerance.