There are disclosed systems and methods for detecting and controlling congestion in an Optical Line Terminal (OLT). The OLT has a plurality of ports. Each port of the plurality of ports communicates with at least one Optical Network Unit (ONU), and each port of the plurality of ports has a respective enforced maximum upstream bandwidth. For example, the maximum upstream bandwidth may be enforced by a Dynamic Bandwidth Allocation (DBA) algorithm. The OLT further includes an uplink port through which data received from each of the plurality of ports are transmitted. In one embodiment, if there is congestion of the data at the uplink port, then the enforced maximum upstream bandwidth for at least one port of the plurality of ports is modified.