Summary - G.9805 (2022) Amd. 2 (11/2025) -

Recommendation ITU-T G.9805 presents three methods for the coexistence of multiple passive optical network (PON) generations on a common optical distribution network (ODN): coexistence element (CE), multi-PON module (MPM), and splitterbased. These methods allow the reuse of already deployed fibre and splitters when evolving a legacy PON to a higher capacity. Methods for calculating required isolation for coexistence element, filter considerations for higher speed passive optical network (HSP) and asymmetric/symmetric 10-Gigabit passive optical network optical line termination or XG(S)-PON OLT, and optical interface parameters for gigabit-capable passive optical network (GPON) and XG(S)PON MPM supporting classes B+, C+ and D optical path loss (OPL) are also described.
Amendment 1 includes additional 3-gen PON systems coexistence methods, and crosstalk analysis between PON systems.
Amendment 2 includes Class C+ and D OPL specifications for G-PON/XG(S)-PON 2-generation MPM and G-PON/XG(S)-PON/50G-PON 3-generation MPM, and specifications for 10GEPON/50G-PON 2-generation MPM and EPON/10G-EPON/50G-PON 3-generation MPM. The 12.5Gbit/s upstream line rate option for 50G-PON is deprecated.