k controller-refers to the platform that implements network control 6.2 IMPLEMENTING NETWORK CONTROL This chapter focuses on the platform that implements network control and allows the separation of control plane from the data plane as well as the creation of abstraction layers, which separates network services and network design constructs from physical network element constructs. The design is for a controller that provides a programmable platform for network tools, network control Software-Defined Networking of service instantiation and management, and for resource and traffic management. The platform also provides a consolidated network management interface to permit the combination of real-time data from the network services and underlying network elements with real-time control of the for- warding plane. The key attributes for this platform are near real-time configuration, real-time flow setup, programmability through service and network script-like logic, extensibility for competitive differentiation, standard interfaces, and multivendor support. In today's environment, automated provisioning is focused on non-real-time configuration management. Real-time redirection of flows is performed by each vendor's control plane, which is normally integrated with the data plane. The future direction is separating this control plane from the data plane and creating a real-time controller, which has a centralized real-time network-wide view, which may optionally complement a local controller that has a nodal view. The initial goal is not to take all intelligent control out of a specific network element, but to pull out the informa- tion needed for functions that need to be performed from a real time and/or a multilayer network perspective-for example, redirecting flows, application of security policies, and multilayer traf- fic engineering. Also in today's environment, the network service and network configurations are intertwined such that if one changes the network element, the network service configuration gets im