A new protection mechanism based on all-optical switching offers a more cost-effective solution for high-speed links, however.
Protection from fiber failures is achieved through the use of redundant fibers. When the primary link fails, traffic is rerouted to an alternate link. To use the redundant fibers, operators have two options: use two sets of equipment at each end (for example, two router line cards at each end of the link), or use a single set of equipment and route traffic to the appropriate link through the use of a protection switch. High data-rate line cards are fairly expensive, whereas protection systems typically cost much less, making their use very cost-effective.
The new protection technology is based on optical switching modules. Optical signals are routed to one of the fiber links without undergoing any electro-optical conversion. Unlike other technologies, optical switches don't use expensive signal conversion circuitry, greatly reducing the cost, space and power consumption of this solution.