Passive Optical Networks

module parameters, there is also a need to monitor fiber link failures, degrad-

ations, and bad connections without disturbing the many ongoing services. Fiber

fault can be detected by using optical time domain reflectometry (OTDR) [71–75].

Recently nonintrusive embedded OTDR approaches have been proposed [76, 77]

to remotely monitor the health of access networks, which will be described in

this section.

4.5.1 Module Parameter Monitoring

Existing SFP and GBIC MSA specifications define a 256-byte memory map

in EEPROM, which is accessible over a 2-wire serial interface at the 8-bit address

1010000X (A0h). The new digital-diagnostic-monitoring interface makes use of

the 8-bit address 1010001X (A2h), so the originally defined serial ID memory

map remains ...