In this paper, we propose the interworking and emulation methods for the interoperability of ABR/ABT capability and algo propose the BCR Re-negotition with State-Dependent (BRSD) mechanism based on the common buffer with two thresholds and the EBCN method when public network hs the ABT capability. As BRSD mechansism has one common buffer for all ABR connectiona and BCR re-negotiation request according to the threshold, it can reduce the queue length and the frequency of ABT BCR re-negotiation. Using EBCN method, BRSD mechanism can prevent the continuous increasing of queue length in the emulation method with the CI bit setting of the ABR performance of the BRSD mechanism in the view poits of the masimum queue length, bandwidth utilization and ABT-BCR re-negotialtion frequency trough the simulation.