Useful life of various elements of FTTH

Comments

[Zed]

Word. It reminds me of another fine way of illustrating the same thing, but using rate of change as the metric. The illustration consisted of concentric circles with RoW in the middle and moving outward with legislation, ducts, dark fiber and active equipement. The circles were drawn as if they were rotating and the speed at each circle's rim being proportional to the rate of change.

I can't for the life of me remember who but it up on his blog, but it was one of the usual suspects.

- Zed

[brough]

Note that I included "Major Changes in Laws and Regulations" as part of the picture... Here 15 years refers to the average time between FCC "Computer" inquiries and the 1996 Telecom act in the US and 35 years refers to the time lapse between Coase's article on spectrum auctions (1959) and the first auction of radio spectrum (in the US in 1994).

Does this suggest anything about which public sector efforts will be most productive over the coming decades?

[brough]

Today I received an email, "I really like the graph you've put online for the life span of FTTH elements. What would be the reason for a life span of 20 years for fibre? Will the quality of the glass degrade, through degradation of the crystalic structure?"

No, there is no degradation that I'm aware of. There is, however, functional obsolescence. In the past 15 years, the performance of single mode fiber has improved dramatically -- less loss, more and wider usable wavelength windows, better tolerance to bending and more fibers per square area, not to mention improvements in connectors and splicing technology. My choice of 20 years was based on normal commercial terms to "purchase" exclusive use of one or more fibers in a cable. The typical purchase agreement is a "20 year Indefeasible Right of Use" usually referred to as a "20 year IRU." So even though the fibers continue to work (perhaps indefinitely), at the end of 20 years (perhaps even sooner), it may make sense to increase the utilization of valuable duct space by replacing the fiber cable.