Combining bandwidth estimate and explicit congestion notification for improving TCP over heterogeneous networks

The challenge for applied TCP over heterogeneous networks is the performance degradation caused by not only network congestion, but also random errors of wireless links. We propose a stable accurate rapid bandwidth estimate (SARBE) algorithm reacting appropriately to Explicit Congestion Notification (ECN), which improves the TCP performance over heterogeneous net-works. Our SARBE algorithm takes advantage of estimating the forward bandwidth of connection to improve the estimated bandwidth more accurate than TCP Westwood. By incorporating the estimated bandwidth of SARBE and the incipient congestion notifications of the intermediate routers, our proposal adjusts the packet transmission rate precisely, according to the causes of packet loss.