Adopting MPEG video traffic to avoid network congestion

Packet loss is widely used as an indication of network congestion over networks which do not provide bandwidth reservation. We use packet loss in conjunction with FEC as a means of congestion control for MPEG video sources. The receiver implements FEC to recover from packet loss. However, the level of packet losses are recorded and transmitted back to the source which acts on this information to adjust the compression ratio and thereby alleviate congestion. We describe a simulation study whereby a real MPEG video sequence with FEC is packetised into IP style datagrams and then transmitted through a simple network based on an output buffered multiplexor. We apply MPEG 1 video traffic sources with FEC to the simulated network using a novel rate based protocol to adapt the compression ratio of the video source to avoid unrecoverable packet loss due to network congestion. Packet loss is used as a measure of congestion at the receiving nodes. The receiving nodes periodically transmit this packet loss information back to the sending nodes. The FEC allows the receiving nodes to recover from the low levels of packet loss which occur at the onset of congestion thereby avoiding considerable video quality loss.<
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