The method of transmitting data packets associated with an importance level comprises a step (305) of estimating available rate on the network. In case a variation is detected in estimated available rate greater than a first predetermined value, determination is made (309-317) of whether there is an increase in the round trip time on said network that is greater than a second predetermined value. If yes, the data packets are transmitted (319-325) at a rate lower than the estimated available rate.In embodiments, in case a variation is detected in estimated available rate greater than a first predetermined value and before the step of detecting an increase in the round trip time, a step (307) is carried out of transmitting packets of lower importance level than the average of said importance levels by using the current estimated available rate and the round trip time is determined on the basis of the sending of those packets.