A Service Function Chain Deployment Method Based on Network Flow Theory for Load Balance in Operator Networks

Network function virtualization technology makes the deployment and management of network service more flexible and elastic by decoupling network function from dedicated hardware. The service requests of network function virtualization are usually deployed in the form of a service function chain. In order to solve the problems of load imbalance, unreasonable utilization of substrate resources, and the high delay of the service function chain deployment in operator networks, a service function chain deployment method based on the network flow theory is proposed in this paper. First, on the basis of perceiving the substrate network resources and topology with a software-defined network controller in real time, a candidate node set is determined according to the resource constraints and the locations of ingress/egress switch nodes that service flow flows in/out. Second, the candidate node set, the ingress/egress switch nodes and the connection between them are used to form a directed network, and the service function chain deployment problem is transformed into an optimal path selection problem. Then, a node disassembling method is used to transform the directed network into a capacity-flow-cost network. Finally, a minimum-cost maximum-flow algorithm is used to find the optimal deployment path and complete the service function chain deployment. Experiments show that the method proposed in this paper can guarantee the load balance of operator networks, reduce the average transmission delay of service flow, and make the utilization of substrate resources more reasonable.