This paper presents UDT version 4 (UDTv4), the fourth generation of the UDT high performance data transfer protocol. The focus of the paper is on the new features introduced in version 4 during the past two years to improve the performance and usability of the protocol.
UDTv4 introduces a new three-layer protocol architecture (connection-flow-multiplexer) for enhanced congestion control and resource management. The new design allows protocol parameters to be shared by parallel connections and to be reused by future connections. This improves the congestion control and reduces the connection setup time. Meanwhile, UDTv4 also provide better usability by supporting a broader variety of network environments and use scenarios.