You are looking at a black box.
Developed by Cisco and now an industry standard (IPFIX), NetFlow is a technology embedded inside nearly every Cisco router and switch running IOS, XE, or XR. It is a metadata generator. It doesn't read the content of your packets (privacy intact), but it reads the conversation —the source, destination, port, type of service, and timestamp. free netflow analyzer for cisco
Go download a free analyzer today. Your users—and your sleep schedule—will thank you. You are looking at a black box