An apparatus and method of providing improved throughput on delay-based congestions comprising a packet engine and a delay-based congestion controller are provided. The packet engine detecting a delay jitter that is caused by a layer 2 retransmission of a data packet, is configured to measure a round trip time (RTT) value. The delay-based congestion controller is configured to receive the RTT value and to determine a smoothed RTT (SRTT) value using the RTT value and one or more moving average functions. The delay-based congestion controller is also configured to, if the SRTT value is smaller than a set minimum SRTT value, assign the SRTT value to the set minimum SRTT value. The delay-based congestion controller is further configured to, if the SRTT value is larger than a set maximum SRTT value, assign the SRTT value to the set maximum SRTT value.