Abstract: In a serial network which includes a hub having a plurality of ports each for attaching one or more stations a mechanism for correlating a list of stations developed in a poll cycle to the ports and for detecting and resolving ambiguities when the number of stations does not equal the number of active ports. The mechanism uses a combination of input and output buffers under control of the programmed hub processor for developing a list of stations connected to the hub. When the number of stations does not equal the number of active hub ports an upstream buffer is configured to transmit Duplicate Address MAC frames to a single port and the contents of a downstream buffer are used to resolve the ambiguity either on a single transmission or multiple single port transmissions.