The analysis of network traces often requires to find the spots where something interesting happens. Since traces are usually very large data-sets, it is often not easy and time intensive to get an intuitive understanding of what happens within a given trace. Through the use of suitable data visualization techniques, it is possible for humans to identify noteworthy spots or characteristics of a trace much faster. Particularly interesting properties of a certain class of network traces are node interaction dynamics, that is how the traffic matrix between nodes evolves over time and the pattern of messages exchanged between nodes. This paper presents some tools visualizing node interaction dynamics that were developed to assist network trace analysts. Key words: network measurement, network visualization, SNMP, NetFlow