AbstractIn this paper, we evaluate the performance of TCP in a network where the IEEE 802.3x flow control and the ATM Available Bit Rate flow control mechanisms are interworked. The objective is to examine whether an interworking of the two flow control mechanisms can improve the performance of upper‐layer protocols like TCP which is an end‐to‐end connection‐based transport protocol. The simulation studies show that the two interworked flow control mechanisms result in high link utilization while providing very low loss rates when used in conjunction with TCP. The flow control mechanisms complement each other. Copyright © 2002 John Wiley & Sons, Ltd.