For reference, please look at the following paper and the references therein: IPACT a dynamic protocol for an Ethernet PON (EPON) https://ieeexplore.ieee.org/document/983911
This is a simple event-driven implementation in OMNeT++ v6.0.3 of Dynamic Bandwidth Allocation (DBA) using Interleaved Polling Cycle Adaptive Time (IPACT) protocol in 1G-EPON.