A network interworking facility (24) advantageously interworks Ethernet and ATM networks (22, 26) having different protocols to permit the data from in one network to pass to the other and vice versa without the need for the source in to account for the protocol of the destination. Upon receipt of an information frame from the source, the interworking facility forms a second frame of a format compatible with the destination network and including the information payload from the first frame. The interworking facility also maps the destination address incorporated in the origin frame to a corresponding destination address of a format compatible with the destination network to facilitate forwarding of the second frame to the destination.