FLOW SYNCHRONIZATION

A controller node receives a list of a first plurality of flows programmed on a network switch. The controller node extracts a flow cookie value from a flow cookie data field of each flow in the first plurality of flows on the received list and calculates a session identifier on the basis of the extracted cookie values. At least one add flow command is transmitted from the controller node to the network switch to program a second plurality of flows on the network switch. The at least one add flow command comprises flow cookie values in the flow cookie data fields of each of the flows in the second plurality of flows which are set equal to the calculated session identifier. At least one delete flow command is transmitted from the controller node to the network switch to delete programming of the first plurality of flows on the network switch.