From Michael J. Hartmann VP Business Development Digital Marketing. 

Optical Fiber Fault Detection must be Fast, Distributed and Pervasive – To materially improve the reliability of the Access Network.

The detection of a fault needs to be fast so that the operation of the network is minimally impacted.  A fault should be detected, located and reported to the Host Switch within a fraction of a second.  If the fault is momentary, then the link should instantly recover.  If not, then there ought to be the capability to initiate a series of diagnostic and repair options.  Such responsiveness to a service disruption may translate directly into improved SLAs and the competitive advantages they may offer the Communications Service Provider (CSP).

A large number of Micro-OTDRs, distributed across the Access Network, makes more sense than fewer, higher performance (and much more costly) systems.

To have the highest level of effectiveness, Micro-OTDRs need to be everywhere.  Virtually 100% fault detection may be achieved when large numbers of (preferably all) optical links incorporate this PHY Layer monitoring.