Techniques and mechanisms for evaluating a transmission outcome indicium to determine a state of data traffic congestion in a network. In an embodiment, congestion information for a packet of a transmission group is evaluated at a computer device to determine a congestion state, where a size of the transmission group is determined based on a congestion window parameter. In another embodiment, the evaluation to determine the congestion state is performed prior to the computer device detecting a transmission outcome indicium for some other packet of the transmission group.