Network management and maintenance has always been an important means for ensuring normal network operation and improving customer perception.As a principal technology for broadband access

Passive Optical Network（PON） is widely adopted by major operators.Therefore

the effective management and maintenance of PON become a major focus of attention and that of Optical Distribution Networks（ODN） is of first priority.Starting with the faults in ODN and the problems in its operation and maintenance

this paper introduces the general situation of the existing ODN

discusses the existing fault diagnosis techniques and analyzes the advantages and disadvantages of various technical schemes and the suitable networking modes and location effects.