A method used for communicating packets or other information units from a server (11) to a client (15) over a communication path including a packet scheduler (14-1) followed by a bottleneck path (14-2), with the packet scheduler (14-1) having a buffer for holding packets so as not to transmit over the bottleneck path (14-2) at a rate either too high or too low, the method providing that the server (11) communicate to the client (15) sender information indicating the last packet sent to the client (11) by the server (11) and do so via a mechanism by which the sender information is communicated over the bottleneck path (14-2) ahead of substantially all packets already in the buffer. The client (11) then uses the sender information to provide, as needed, information useful in adapting the rate at which the packets arrive at the packet scheduler (14-1)