Understanding Network Equipment Reliability


This paper reviews the concepts and techniques that have been adopted by BT in order to understand network equipment reliability. The ideas presented are largely generic, in the sense that they can be applied irrespective of whether the equipment is intended for a core network or an access network application. In particular, the paper examines the relationship between out-turn reliability and the reliability that might be guaranteed by an equipment manufacturer. The relevance of confidence limits to reliability modelling and in-service reliability monitoring is also discussed, and ideas presented on how reliability monitoring can be applied to resilient networks. It is shown that in competitive situations, there are good reasons why reliability modellers should use failure rate data whose upper confidence limit is 50%. In contrast, it is shown that for practical reasons, in-service monitoring schemes should not be based on specific confidence levels.

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Ford, D.J. Understanding Network Equipment Reliability. BT Technology Journal 16, 180–186 (1998). https://doi.org/10.1023/A:1009616418109

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  • User Interface
  • Failure Rate
  • Confidence Limit
  • Practical Reason
  • Access Network