Method of monitoring a connectivity of an optical network terminal to an optical output port of a remote node in an optical access network, comprising - at a network analyzer, transmitting a control signal indicating a request for modulating a power level of an optical downstream signal at a dedicated optical output port of a remote node, - at a controller, receiving said control signal from said network analyzer or retrieving said control signal from a data base and furthermore transmitting an output control signal indicating said dedicated output port of said remote node via a control channel to said remote node in dependence on the received control signal or the retrieved control signal, characterized by - at said remote node, receiving via said control channel said output control signal indicating said dedicated output port and furthermore activating an optical modulation device present at said dedicated output port, - at said optical network terminal, indicating reception levels of a received downstream signal for successive time instances, - at an optical line terminal, receives the indicated reception levels from said ONT in a periodic manner, deriving from said reception levels reception level data and providing said reception level data to said data base, which stores said reception level data, - at said network analyzer, retrieving said reception level data from said data base, wherein said reception level data indicates said reception levels of said downstream signal for said successive time instances, and furthermore deriving a potential connection of said optical network terminal to said dedicated output port, and wherein said network analyzer derives said potential connection in the case, that the reception level of one time instance differs to reception levels of one or more following successive time instances by more than a pre-defined threshold. - at a network analyzer, transmitting a control signal indicating a request for modulating a power level of an optical downstream signal at a dedicated optical output port of a remote node, - at a controller, receiving said control signal from said network analyzer or retrieving said control signal from a data base and furthermore transmitting an output control signal indicating said dedicated output port of said remote node via a control channel to said remote node in dependence on the received control signal or the retrieved control signal, - at said remote node, receiving via said control channel said output control signal indicating said dedicated output port and furthermore activating an optical modulation device present at said dedicated output port, - at said optical network terminal, indicating reception levels of a received downstream signal for successive time instances, - at an optical line terminal, receives the indicated reception levels from said ONT in a periodic manner, deriving from said reception levels reception level data and providing said reception level data to said data base, which stores said reception level data, - at said network analyzer, retrieving said reception level data from said data base, wherein said reception level data indicates said reception levels of said downstream signal for said successive time instances, and furthermore deriving a potential connection of said optical network terminal to said dedicated output port, and wherein said network analyzer derives said potential connection in the case, that the reception level of one time instance differs to reception levels of one or more following successive time instances by more than a pre-defined threshold.