Interworking of first and second networks (12, 14) is accomplished by an interworking facility (30) that serves to map the destination address in first frames received from the first network into second destinations addresses compatible with the second network. To conserve such mapping the assignments, the first network encapsulates information frames (32) received from one or more sites associated with a first customer into jumbo frames (34) that have a generic address associated with that customer. At the interworking facility, the individual frames are stripped from the jumbo frame and routed to corresponding destinations in the second network.