Patent attributes
Hierarchical Software Defined Network (SDN) architectures can be used to reduce complexity of traffic engineering in large or diverse network environments. In hierarchical SDN architectures, a network is sub-divided into multiple regions, and each region is assigned to a different SDN controller. Network status information is collected and consolidated at a regional level, and fed upstream through the SDN control plane until it reaches a root SDN controller. The root-SDN controller computes cost-based parameters, which are distributed to regional SDN controllers for local provisioning. The cost-based parameters can include Lagrangian variables estimations or other parameters that constrain regional traffic engineering optimization in a manner that advances global traffic engineering objectives.