Availability objectives for fiber in the loop systems

It is noted that deployment of fiber in the loop (FITL) involves more than the simple replacement of copper media with optical fiber; it requires the introduction of additional equipment, primarily related to the optoelectronics obviously necessary for fiber optic transport, and a careful reexamination of maintenance strategies. Although the end-to-end service availability objective (99.99%) is not changed in proposed Bellcore criteria, FITL leads to a new hypothetical reference circuit (HRC) and subsequent reallocation of maximum downtimes assigned to different network elements. These changes are reviewed, and some critical system and component issues are identified. The downtime allocations described, based on the new FITL HRC, give equipment suppliers clear reliability goals for the design and manufacture of their products