NetWitness NextGen is a network security monitor. The heart of the monitor is the Decoder subsystem that records network traffic for analysis. The Investigator is a protocol analyzer meant to be run on captured traffic.
For downloads and more information,
visit the NetWitness NextGen homepage.
Love this tool, I'd buy it myself if it had Unix support.
Great tool for getting a handle of everything in a pcap and finding non-trivial bad stuff.