There is one physical light path, which is 2.4Gbps downstream and 1.2Gbps upstream. This is shared by all the ONTs on the same splitter. In the downstream direction, all ONTs receive the same 2.4Gbps stream, but discard data which is not addressed to them. In the upstream direction, each ONT takes it in turn to transmit; this is controlled by the OLT assigning timeslots. Transmit and receive are on different wavelengths and occur simultaneously.
Individual services are then timesliced out of this, and limited to the contracted speed. e.g. if you have a 330/50 service then the OLT at the other end will send you individual packets at 2.4Gbps, but rate limit them so that your total average data rate is 330Mbps. And upstream, the OLT will not allow you to send more than 50Mbps, since it controls the timeslots.
If you have a multi-port ONT, then it can present separate services on each ethernet port. As far as the end user is concerned, this behaves the same as if they had multiple separate ONTs.
Edited by candlerb (Mon 28-Jan-19 19:47:51)