A method for determining the state of an entire network, including state of applications and infrastructure includes receiving network control messages in an OpenFlow network, passing normal network control messages through OFSense, a control plane middleware, and constructing from the network control messages an application level connectivity graph to infer network delay between any two communicating server in the network and estimating an application response time of a given server in the network; and providing state of the network for enabling intelligent detection and diagnosis of infrastructure and application performance.