Reliability by design – in practice and in the field
of Reliability by Design. By this, we mean that the reliability impact of all design decisions, from the network architecture level to the equipment component level, is understood in terms of physics rather than merely statistics. Through the use of this Reliability by Design principle, we have consistently delivered highly reliable submerged equipment. Since the beginning of the 980-nm repeater program in 1999, we have installed more than eleven thousand 980-nm amplifier-pairs in approximately 2,200 repeaters, accumulating more than 180 million component service-hours. To date, we have not had a single observed service-affecting repeater failure or 980-nm laser diode failure in these repeaters.
Dr. Barbara Dean and Dr. Jeff Gardner
Undersea telecommunications systems represent a substantial investment to network owners. Continuous operation of these systems ensures an on-going revenue stream and is a pre-requisite for end customer satisfaction and retention. There are numerous ways in which the outage risk of undersea systems can be reduced, including geographically diverse cable routes, judicious armoring and burial of cable, and advanced network protection switching protocols. After proper route planning and network architecture engineering, one of the most
Tyco Telecommunications Laboratories
Typical Reliability Requirements for Undersea Systems
important factors in minimizing outages is ensuring high reliability of the submerged equipment, so that ship repairs are minimized. Ship repairs represent a considerable cost to the network, since recovery and repair of the system is a lengthy and expensive process during which the network owner typically purchases restoration capacity, incurring even greater expense. The reliability record of a supplier is therefore an important metric which guides customers in their choice of system supplier. Reliability management at Tyco Telecommunications is driven by the principle
The industry metric for the reliability of submerged equipment is the expected number of ship repairs over a 25 year system life. The general industry target is fewer than 2 ship repairs, excluding faults due to external aggression, for a 7,000-km long system with four fiber pairs. To interpret what this target means in terms of submerged equipment reliability, if this 7,000km system were deployed using a typical network design, each repeater in the network would require a probability of failure of less than 1% over the life of the system.
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