Summary - G.984.3 (2014) Amd. 2 (11/2025) -

Recommendation ITU-T G.984.3 describes the transmission convergence layer for gigabit-capable passive optical networks – a family of flexible access networks capable of providing a range of broadband and narrow-band services, operating at the rates of 2.48832 Gbit/s downstream and 1.24416 or 2.48832 Gbit/s upstream. This Recommendation includes the specifications of the following:
•gigabit PON transmission convergence (GTC) layer framing;
•upstream time division multiple access mechanism;
•physical layer operation, administration and maintenance (OAM) messaging channel;
•principles and signalling mechanism of the upstream dynamic bandwidth assignment;
•optical network unit (ONU) activation method;
•forward error correction;
•security.
This Recommendation forms an integral part of the G.984-series of ITU-T Recommendations that, together, specify a single coherent set of access transmission systems.
Amendment 1 provides necessary extensions to support Class D ODN. Amendment 2 implements the TC layer consistency updates across the ITU-T PON specifications including Deactivation Reason Codes and Forgotten ONU timer.