This month's column looks at APS methods that can help engineers navigate around these situations. When protection switching occurs, payload services are generally restored within 50 ms. The work facilities are those that carry the live traffic. Protect facilities refer to the portions of the network available for traffic if the work portion of the network fails. Backhoe fade .
Optical communications run over fibers that work best when intact.
When the fibers run in conduits alongside roads, railroads, and utility lines of passage, occasional construction accidents can occur. Backhoes digging into the ground can break into these conduits, rendering the various facilities useless. Equipment failures . However, these requirements are statistical in nature, and problems and faults can occur. Mechanical failures .