Patent ID: 7369498

Claim:
A method for controlling congestion in a packet-switched network, comprising traffic sources, traffic destinations and network nodes, said method comprising: determining a packet queue length in a network node; transmitting a congestion notification back towards the source address of an incoming data packet received at said network node, if the detected packet queue length exceeds a predetermined threshold; and performing congestion control at a predetermined intermediate network node in response to receipt of said congestion notification; wherein said congestion notification is indicated by setting a predetermined bit in a header of said incoming data packet, and another predetermined bit of the header of said incoming data packet is used to indicate that the queue length has dropped below said predetermined threshold, wherein said congestion control is performed by controlling the rate of acknowledgements routed through said intermediate network node, and wherein a new acknowledgement rate is calculated at said intermediate network node based on a respective one of the following conditional relationships: P new =P old *R 1( R 1<1), if said congestion indication has been received, or P new =P old +R 2 *P max ( R 2<1), if a congestion relieve indication has been received, wherein P min <P new <P max , and wherein P old denotes the acknowledgement rate before the change, P new denotes the acknowledgement rate after the change, P min denotes a minimum acknowledgement rate not larger than a round-trip time, P max denotes a maximum rate equal to an access link speed, and R1 and R2 denote predefined parameters.