Transport-layer protocols for high-speed and long-delay networks

In this report, we discuss the modifications of the congestion control mechanism of TCP, which is the major transport-layer protocol in the current Internet, for high-speed and long-delay networks. We categorize them by the network congestion indications which a TCP sender utilizes to increase/decrease its congestion window size. We also introduce recent works of our research group, which is an inline network measurement method which measures the bandwidth information of the network path between sender and receiver hosts, and TCP Symbiosis which control its congestion window size based on the measured bandwidth information.