A management device (100) for use in an access network (10, 19, 20, 30, 40, 100) including a plurality of data connections (18, 19, 20) between end user devices (10) and an aggregation transceiver device (20) where the connections (18, 19, 20) are aggregated for onward connection through the access network (20, 30,40), the access network storing in association with each data connection a Dynamic Line Management, DLM, profile which specifies a set of values for a plurality of parameters associated with the respective data connection, together with a stability level specifying a desired level of stability for the data connection. The device comprises means for receiving monitoring data specifying the stability of each respective data connection over a predetermined period of time; means for selecting a DLM profile to be applied to the connection in dependence on both the monitoring data and the stored stability level associated with the data connection; and means for requesting an OSS system of the access network to apply the selected profile to the data connection.