A method of treating signals in a bridge-based radio access station backbone network including a plurality of base station bridges (BSBs), with each BSB having a 2-tiered switch connected with a plurality of radio access stations. A plurality of SCBs (Site Core Bridges), each of having a 2-tiered switch for constituting the core network, includes the steps of buffering by the SCB a predetermined number of previously-transmitted frames when operating as a crossover bridge, and causing the SCB to retransmit selected ones of the buffered previously-transmitted frames to a terminal in response to a handover completion signal.