A method of passively measuring available link bandwidth at a client device that receives media data over a network connection comprising receiving packets of a media stream at the client device, wherein one or more the of packets comprises a unique identifier indicating that one or more the packets are associated with a macro burst sorting the received packets into one or more of the macro bursts based on the unique identifiers, and determining the link bandwidth available to the client device based at least in part on the time intervals between arrival times of the packets sorted into individual macro bursts, wherein the macro bursts each comprise a plurality of packets transmitted together by a sending device to regulate the sending device's transmission rate.