Protecting PONs: A failure impact, availability and cost perspective based on a geometric model

Passive Optical Networks (PONs) are regarded as the preferred technology for broadband access networks. PONs provide high capacity and low-power consumption at a low-cost deployment. Besides, the dependability of PONs is becoming more important as end-users also expect access networks to be highly reliable. Operators, on the other hand, are more concerned about reducing the number of clients affected by failures (i.e. failure impact) while keeping the costs at reasonable values. This paper identifies the best suited protection schemes for PONs, and gives a deep insight into how the access network layout and design decisions affect the performance of these schemes. To achieve this goal, the PON deployment area is described by means of a network geometric model. Then, different protection mechanisms are deployed following this model and evaluated in terms of failure impact, availability and cost. In this manner, the performance of the protection schemes is assessed, taking into account the effects of the network layout on these three parameters. Moreover, the trade-offs between failure impact, availability and cost caused by design decisions are also pinpointed.