Availability and cost estimation of secured FTTH architectures

In this paper are presented the availability and the relative deployment costs of secured and non secured GPON architectures. The perimeter considered ranges from the OLT shelf to the ONT. Unavailability and failure frequency of tree and bus architectures were reported for three distinct deployment scenarios. The same calculations were performed for four secured architectures based on tree and bus architectures. The relative deployment cost of the secured architectures compared to the tree architecture has been estimated. This study reveals that the tree and bus architectures have, with the input parameters considered in this study, an unavailability of about 1 hour. Unavailability falls below 5 min/year for a doubling of the costs in case of complete redundancy of the architecture. Comparatively to the tree architecture, a decrease of 9 min/year is acquired with an extra cost of about 10% in case the most shared part of the optical distribution network is protected against single fiber failure. For the four investigated secured achitectures, the relative cost extends from 2.3 to 1.1 with respect to the tree architecture.