Patent ID: 8509085

Claim:
An edge node for a network domain that comprises at least one ingress node for receiving and routing data units belonging to a plurality of flows into said network domain, a plurality of interior routers for routing said data units through said network domain, and at least one egress node for routing said data units out of said network domain, at least one of said interior routers being arranged to detect whether it is subject to a congestion condition and to congestion mark routed data units if it is subject to said congestion condition, said edge node being arranged to act as said egress node and comprising: a control element arranged for performing a congestion handling function that comprises a detecting part, for detecting the presence of congestion marked data units arriving at said edge node, said congestion marked data units including a first marker or a second marker, said first marker indicating that a traffic load at an interior node exceeds a first load threshold and said second marker indicating that a traffic load at an interior node exceeds a second load threshold corresponding to a higher load than said first load threshold, a reacting part for reacting to the detection of the presence of congestion marked data units by invoking a congestion control process that comprises: a) in response to the detection of congestion marked data units that include the second marker: i) setting a value of a load reduction parameter in response to the detection of congestion marked data units that include the second marker, and ii) sending to said ingress node an instruction for terminating one or more flows to reduce a traffic load in accordance with said value of said load reduction parameter, b) waiting a predetermined period of time and then determining whether congestion marked data units that include the second marker are still arriving at said edge node, and c) if congestion marked data units are still arriving, repeating steps a) and b).