Large enterprises are moving towards Software Defined Network (SDN) adoption, where business-critical applications are being deployed on top of highly programmable network components and orchestrated by a single or multiple controllers using network protocols, such as OpenFlow or NetConf for communication. Just like in traditional networks, low-cost monitoring solutions need to be developed for SDN. The issue of inaccurate network traffic tagging and amount of overhead associated with using traditional monitoring techniques based on packet sampling or Deep Packet Inspection (DPI) need to be addressed. These traditional techniques are no longer satisfactory for monitoring in SDN. This paper presents FlowVista - a lightweight solution to identify flows using the SDN Northbound interface and addressing flows rather than packets. The high flow matching accuracy is achieved by interacting directly with business application residing in the application layer and translating its high level information to low level network flows in a non-invasive fashion. FlowVista is tested using Voice over IP (VoIP) as a business-critical application in both real and simulated networks. In addition, the portability across various platforms, low bandwidth utilization characteristics and integration with many components native to SDN makes FlowVista suitable for those who want to analyze SDN traffic without having to attach expensive tools that often have limited visibility and granularity.