You can also enable QoS on a physical interface (you don't need to actually use it for anything, just enable it). This will then activate a Statistics link on the Network --> QoS page for that interface. If you click that link, you get a real-time view of the network traffic passing through that physical interface. And there are sub-tabs in that dialog that shows the Applications, Source/Destination Users, Security Policies, and QoS Policies that are generating the traffic. The data displayed is for the last 60 seconds worth of traffic, I believe.
... View more