Listens to all available traffic on the interface of your choice, figures out who’s talking to who, how much, using which protocols. This information is then put into a nice human-readable 2d image (various formats are available) which can be used to understand a network’s topology.
lan map can be executed with this simple command (depending on your interface, mine is ath0):
lanmap -i ath0 -r 30 -T png
For better examples of screenshots: http://parseerror.com/lanmap/gallery/