Improving the Efficiency of Multipath Transport Protocols

Smart devices equipped with multiple network interfaces are becoming commonplace. However, even when multiple interfaces are successfully connected to the Internet, traditional TCP/IP typically continues to use only a single default interface for data transmission. It has become one of the unsolved issues in today's Internet to improve performance and robustness by aggregating multiple network paths simultaneously. This thesis investigates how to improve the effciency of multipath transport protocols. In multipath transmission, for instance, one of the key challenges is to effectively multiplex paths with mismatched characteristics in terms of bandwidths, delays, and loss rates. The first solution is to utilize the redundancy of systematic packet coding so as to compensate for missing packets with a light overhead. This redundancy is updated in a timely fashion according to the dynamic path characteristics, and a pre-blocking warning mechanism is triggered in the case of proactive redundancy underestimation. In the second solution, the timeout impact on aggregate goodput and receive buyers is analyzed. Moreover, the minimum timeout constraint is removed at the sender, while the delayed ACK function is reserved at the receiver. In data center networks, the investigation focuses on the sharing of network resources among multiple transport ows in the many-to-one traffc pattern. The solution mitigates the Incast collapse problem in both single and multi-homed topologies by using an equally weighted congestion control algorithm.