|| Tvark is a network monitoring tool (sniffer) with a GUI front end and is tied to a MySQL database. The GUI provides a view of traffic activity that can be seen from the machine/interface that Tvark is run on. What you see is a list of source nodes on the left, destination nodes on the right, and lines drawn, left to right, showing traffic flow.
Tvark runs in "realtime", meaning you see the traffic roughly as it happens. There is a small delay between actual traffic flow and the display because buffering of traffic information was necessary to be able to determine rate information. The color of the nodes, and the lines between them, provide an indication of rate of traffic.