At an application executing in conjunction with a vSwitch in a host system, using a processor assigned to the vSwitch in the host system, a CWND value corresponding to a flow from a VM is computed using a period measured by a timer and a number of packets of the flow received and acknowledged in response packets, the number being counted by a counter, the timer being associated with a packet of the flow. A set of flow parameters is extracted, at the application, from the flow. At the application, a normalized value corresponding to the flow is computed. At the application, the CWND value is reduced according to the normalized value of the flow to form a reduced CWND value. The reduced CWND value is applied to the flow at the vSwitch such that the vSwitch transmits, from the flow to a network, only a number of packets up to the reduced CWND value.