Here is an example of an SDN Application using the Big Switch OpenFlow controller to provide flow monitoring of your network. Stace Hipperson from Real Status has linked their HyperGlance 3D visualisation tool to capture flow data and display it in an quite useful way. Watch the video and consider what this means for troubleshooting a path [...]
Some packet generator are more important than others and indeed while a packet is just a packet for us network people if the packets stop moving around the network the way they should it can be a great cause for alarm. I have a customer with such a packet generating devices and it chucks out a 600k udp multicast stream (a single UDP payload) every 5 seconds and if this screws up for any reason then the application is not happy and hundreds of users are very upset. If the packets stop for any length of time then a Severity 1 incident is raised and the customer needs an ass to kick.