Patent ID: 7209437

Claim:
A method of transmitting data stream of packets from a server computer to a client computer over a communications network, said stream of packets being routed between the server and client computers by a packet network node; the packet network node having an input to receive said stream of packets from the server computer, the input being connected to first and second packet queues, said packet queues being connected to an output channel of predetermined bandwidth, wherein the first packet queue is preferentially allocated a portion of an output bandwidth and the second packet queue is allocated a remaining portion of the output bandwidth such that packets received in the first packet queue are transmitted in preference to packets received in the second packet queue; the method comprising: (i) transmitting packets in said stream of packets from the server computer to the client computer via the first packet queue of the network node; and (ii) upon receipt by the server computer of a first control signal from the client computer, transmitting subsequent packets in said stream of packets from the server computer to the client computer via the second packet queue of the network node; wherein packets received at the network node are directed to said first or second packet queues in dependence upon the presence of a first or second identifier respectively in said packets; and said server computer transmits packets containing said first identifier prior to receiving said first control signal and after receiving said first control signal transits packets containing said second identifier.