This paper discusses fiber characteristics and cable design considerations that affect cable reliability. Installed cable and splice reliability data are presented, and it is concluded that intrinsic cable and splice reliability is very high. Cable failures are dominated by uncontrollable factors, and the highest failure mode is "backhoe blackout." Finally, restoration issues are discussed.

The experience obtained during the installation of more than 700 sheath km of fiber-optic cable is summarized. These include in-building, underground (duct), aerial, buried, and underwater installations. In general, no special precautions are required except to maintain the specified pull tension and cable bend radius. Field splicing is discussed and results are given on splice losses with and without splice loss monitoring with the optical time domain reflectometer. A 28 percent learning curve for fusion splicing is derived. Reliability data on 312 sheath km of installed cable and field splices are presented. Most of the cable failures were in the "uncontrollable extrinsic category," and most of these were due to complete cable cuts. Finally, restoration is reviewed with emphasis on troubleshooting, repair, emergency restoration, and offset breaks.