http://packetstormsecurity.nl/sniffers/netwatch/ http://mops.uci.agh.edu.pl/doc/netwatch/

Netwatch is ncurses-based ethernet sniffer and monitoring tool. Similar to Statnet, but with nicer graphics and more features.

Netwatch monitors ethernets for hosts, packet counts, protocols and displays in ncurses format with colors indicating hosts activity

less than 1 minute RED,
less than 5 minutes YELLOW,
less than 30 minutes GREEN and
otherwise BLUE

provides an ethernet "top" program for isolating high bandwidth hosts, allows selection of individual hosts (Remote or Local) and monitors the transmissions, provides Router statistics using passive monitoring (rather than querying the router box itself), much more.