A new synchronous flow control scheme for ATM retworks is proposed in this paper. Thescheme could allocate bandwidth fairly and efficiently.The rate of an ABR source would go up increasingly. Byintroducing Vinual Nodes. the transient durations experienced by ABR connections are further reduced.The per-formance of SER scheme is investigated with simulations . As a result
transient durations are very short . Thelength of queues accumulated at switch ports are also very short.