Failure Impacts, Survivability Principles, and Measures of Survivability

In this chapter we will look at causes of fiber cable failures, identify the impacts of outage, and relate these to the goals for restoration speed. We then provide an overview of the different basic principles and techniques for network survivability. This provides a first overview appreciation of the basic approaches of span, path and p-cycle based survivability which we treat in depth in later chapters. The survey of basic mesh-oriented schemes in this chapter also lets the reader see these schemes in contrast to ring-based schemes that are 100% or more redundant, and which we do not consider further in the book. The chapter concludes with a look at the quantitative measures of network survivability, and the relationships between availability, reliability and survivability.