Optical Cable Redundancy Efficiency for a Long-Reach Passive Optical Access Network Taking Into Account Common Cause Failures

The efficiency of an optical cable redundancy for a long-reach passive optical access network is considered, taking into account common cause failures in conditions of both gradual and sudden failures. To evaluate the effectiveness of using a particular method to increase the reliability of an optical cable through redundancy, the ratio of the quantitative characteristics of a redundant optical cable to the same quantitative characteristics of the cable without redundancy is used. For sudden failures, the reliability function is used as a dependability characteristic, and for gradual failures, the optical cable lifetime is used. The problems of evaluating the effectiveness of permanent optical cable redundancy and redundancy with substitution are discussed in the article. At the same time, sudden and gradual failures are considered separately, and the impact of common cause failures and so-called individual sudden failures is assessed. The latter include all types of failures except common cause failures.