FTTx network designer should consider possibilities of necessity of parallel fiber for the redundancy purposes. Installation of such solution would increase the reliability, but is it worth the costs? Analyzing the construction costs, frequency of line cuts and revenue from parallel lines would determine that the costs of redundant paths to each end-point would be significant compared to the revenues. Even the installation of additional paths, which would be physically separated from original one, that would go to most businesses would be covered by the revenues.
Unfortunately, due the Internet learning, anyone could create the web-site and start own business from home, which makes impossible to determine difference between the residential and business customers allocation zones. Since business are coexisting together with private residences, the traditional “residential neighborhoods” must allow installation of redundant paths to the home-based business. The amount of these installations would be increasing with the development of home-based business. In order to support and provide redundant connection, it would require additional 10% of fiber for each neighborhood.
Next question in design would be: How many Fiber Strands is required?
For the typical residence, only one strand is enough, while in theory one strand can provide up to 150 Tbps capacity. For the business, MDUs and MTUs – redundant connection and/or multiple fibers are required.