On sait si les adaptateurs fibre des anciennes FB en zone PON sont des ONU 1Gb, ou bien des ONU 10Gb avec bufferisation / downrate 1 Gb côté SFP/box ?
Car le mélange 1Gb / 10 Gb ne pose pas de souci en downstream car longueurs d'ondes différentes, donc pas trop d'intérêt à séparer les arbres (au contraire ça permet de lisser le débit en amont d'OLT).
The 802.3av standard places significant emphasis on enabling simultaneous operation of 1 Gbit/s and 10 Gbit/s EPON systems on the same outside plant. In the downstream direction, the 1 Gbit/s and 10 Gbit/s channels are separated in the wavelength domain, with 1 Gbit/s transmission limited to 1480–1500 nm band and 10 Gbit/s transmission using 1575–1580 nm band.
In the upstream direction, the 1 Gbit/s and 10 Gbit/s bands overlap. 1 Gbit/s band spreads from 1260 to 1360 nm; 10 Gbit/s band uses 1260 to 1280 nm band. This allows both upstream channels to share spectrum region characterized by low chromatic dispersion, but requires the 1 Gbit/s and 10 Gbit/s channels to be separated in time domain. Since burst transmissions from different ONUs now may have different line rates, this method is termed dual-rate TDMA.
Various OLT implementations may support 1 Gbit/s and 10 Gbit/s transmissions only downstream direction, only upstream direction, or in both downstream and upstream directions.