An appliance for controlling data transmission is described. The appliance includes a packet engine configured to acquire data regarding a flow of first data packets over a link and to determine transport communication protocol (TCP) characteristics for the flow. The appliance also includes a data transmission controller configured to receive second data packets, determine a rate of transmission based on the TCP characteristics, and determine, based on one or more criteria, whether to use a rate-based data transmission control to control a transmission of the second data packets. The data transmission controller is also configured to, responsive to determining that a rate-based data transmission control is to be used to control a transmission of the second data packets, cause the packet engine to transmit the second data packets in groups, wherein transmission times of each group of second data packets are determined based on the rate of transmission.