1. A mediator device in a management communications stream established between a network element (NE) and network management systems (NMS), the mediator comprising: a southbound interface for exchanging management data with the NE; a signal processor for processing the management data from the southbound interface to provide management data associated with a management representation of the NE, the management representation corresponding to a logical NE based on a predetermined proportion of resources of the NE; and a northbound interface for exchanging management data associated with the management representation with the NMS; wherein the signal processor comprises a filter for the northbound interface, the filter inspecting individual packet content and discarding from individual packets management data received from the southbound interface that is not associated with the management representation of the logical network element, and wherein the filter is associated with a respective mutually exclusive set of the predetermined proportion of resources of the NE, and only admits management data associated with that predetermined set of resources.