A client/receiver downloads data over a network path between a source and the receiver coupled by the network path and stores the media data in a presentation buffer of the receiver and from there it is consumed by a presentation element. The receiver monitors a presentation buffer fill level that represents what portion of the presentation buffer contains media data not yet consumed by a presentation element. The receiver makes requests for additional data to download. If the fill level is above a high fill threshold, the receiver does not make further requests and eventually the fill level goes down. If the fill level is below a low fill threshold, the receiver restarts the downloading and updates the fill level as media data is consumed by the presentation element. The fill level might be measured in units of memory storage capacity and/or units of presentation time.