This Recommendation addresses the general characteristics of Gigabit-capable Passive Optical
Network (GPON) systems, in order to guide and motivate the physical layer and the transmission
convergence layer specifications. The general characteristics include examples of services, User
Network Interfaces (UNI) and Service Node Interfaces (SNI) that are requested by network
operators. Also, this Recommendation shows the principal deployment configuration.
As much as possible, this Recommendation maintains characteristics from ITU-T Rec. G.982 and
G.983.x series of Recommendations. This is to promote backward compatibility with existing
Optical Distribution Networks (ODN) that complies with those Recommendations.
GPON systems are characterized, in general, by an Optical Line Termination (OLT) system and an
Optical Network Unit (ONU) or Optical Network Termination (ONT) with a passive Optical
Distribution Network (ODN) interconnecting them. There is, in general, a one-to-many relationship
between the OLT and the ONU/ONTs respectively.