A data traffic scheduling method that includes selecting, using a network controller, plurality of flows that traverses a network node, generating an augmented graph based on a flow rate of the plurality of flows and link capacities of the network node, computing a flow schedule for the flow using the augmented graph to minimize delay or delay variance of the flows, and outputting the flow schedule. A data traffic scheduling method that includes obtaining, using a network controller, a network topology for a network, generating an augmented graph based on the network topology, converting the augmented graph to a mixed-integer linear program, scheduling a flow in the network using the mixed-integer linear program to minimize delay or delay variance of the flow, and outputting a flow schedule.