'Institute of Electrical and Electronics Engineers (IEEE)'
Abstract
Passive Optical Networks (PONs) are one of the
preferred technologies to deploy
broadband access networks. As
time passes, end users presuppose network connectivity to be
always available, and expect PONs to be highly dependable. Yet
operators, from an economic view, are interested in the costs
related to failures. Thus, PONs dependability and associated
costs have been extensively studied, but only focusing on
hardware failures. Contrarily, this paper performs a thorough
analysis of the impact of software failures in failure-related costs.
Based on real empirical data, software failures are thoroughly
characterized and classified in four different categories according
to their severity. Also, the effect of software failures on the
behavior of PON’s fiber protection and recovery mechanisms is
detailed. Software failures are included into a Markov cost
model, implementing a comprehensive cost framework. This way,
the dependability-related costs of
PONs are analyzed, accounting
for hardware and software failures, as well as for the
consequences of software failures on well-known PON protection
mechanisms. Moreover, how the testing phase duration and user
profile (residential or business) impact these costs is pinpointed