In fact, the UDT project can be treated as two orthogonal elements: the UDT protocol and the UDT congestion control algorithm. The UDT protocol can work with many different congestion control algorithms, whereas our congestion control algorithm can be used in other protocols. (For example, using it in TCP to form a new TCP variant.)
On the one hand, the protocol design and implementation decides the functionalities of a protocol, and it also contributes partly to the efficiency. On the other hand, the congestion control algorithm decides the characteristics of fairness, friendliness, stability, and part of efficiency.
Note that both of the two elements have an impact on the efficiency. The former affects the efficiency through the usage of the processor time, whereas the latter through the tuning of data sending rate.