End-to-end TCP performance in Ethernet/ATM networks

Enterprise networks using Ethernet switches at the edge of the network and ATM switches in the core of the network have become a common model in the industry. In such networking environment, TCP is used as the end-to-end flow control mechanism (transport layer) and ABR as the edge-to-edge flow control mechanism (link layer). It is well known that ABR pushes congestion to the edge of the network, thereby alleviating congestion in the ATM network but resulting in buffer overflows and packet losses at the interworking Ethernet/ATM unit, thus degrading end-to-end performance. We investigate the interworking behavior between the TCP flow control mechanism and ABR flow control mechanism, and show that appropriate buffer provisioning in the edge devices results in acceptable TCP performance. However, fairness between competing connections is not perfectly achieved. We also show that different TCP flavors exhibit distinctive performance behavior.