FirePlotter is a real-time session monitor for your firewall. FirePlotter, simply shows you the traffic that is flowing through your internet connection moment to moment - in real-time. FirePlotter can also be described as a firewall vizualization tool, or a bandwidth analyzer or a connection monitor for your Cisco ASA/PIX firewall or FortiNet FortiGate firewall. FirePlotter can replay all the session data it collects.
http://www.fireplotter.com