Creating logical zones for hierarchical traffic engineering optimization in SDN-empowered 5G

Software defined networking (SDN) decouples control plane functionality from the data plane and performs traffic engineering (TE) through a central SDN controller. Centralized TE is impractical when the network becomes too large in size or in loading. Zone-based hierarchical TE comes into play under this circumstance, where the TE problem is decomposed into sub problems related to zones and tackled collectively by local zone controllers. As an integral part of this TE approach, zoning was studied in a very limited context. Existing solutions generate geographic zones and suit only arc-model TE optimization. In this paper, we advance the state of the art by proposing logical zones to support path-model TE optimization. Logical zones are created by coupling traffic flows to zone controllers. We mathematically formulate the zoning problem in different cases, where the number of available controllers is equal to, or larger than that of zones required. These problems are NP hard. We develop novel heuristic solutions and present comparative simulation study.