P-XCP: a transport layer protocol for satellite IP networks

Explicit control protocol (XCP) is a promising transport layer protocol for satellite IP networks. Nevertheless, two problems of XCP can be identified: low throughput under high link error rate conditions; output link underutilization in the presence of rate-limited connections. To address the first problem, we propose to maintain the transmission rate of an XCP sender when triple duplicate ACK is detected. To solve the second problem, we propose to adjust the aggregated feedback based on the ratio of the number of rate-limited connections to the total number of connections sharing the link. We then combine our proposed solutions to form a new protocol, called P-XCP. Simulation results show that P-XCP overcomes the two problems of XCP. When packet error rate is over 0.1, P-XCP is shown to enjoy a throughput almost double that of XCP.