If you want to compare the feature-set of your NIDS then I suggest you look at Security Onion, is an awesome Linux distro for IDS (Intrusion Detection) and NSM (Network Security Monitoring). It's currently 32-bit and based on Xubuntu 10.04 and contains Snort, Suricata, Sguil, Squert, Snorby, Bro, NetworkMiner, Xplico and many other security tools. I'd recommend checking out
IMHO, for a NIDS device to be useful, it has to be a NSM. Many NIDS failed because they were simply installed due to some regulation, compliance request or recommendation from a Big-4 consultant (not dissing all Big-4 consultants, some are excellent such as Rory...this regularly happened) and the internal staff managing the NIDS device could barely spell TCP/IP. You have to think of usability:
- ease of use
- ease of install
- ease of understanding
- ease of turning the alerts into something human-understandable by management
Security Onion is a complex beast that's been around for 3 years now (I think) so is far from baseline but check it out and take the pre-requisite features. It's also worth installing to see how Doug has implemented his solution. It's been actively used in very large environments so it's definitely relevant for your project.
It is going under a complete rebuild to x64 as a fyi.
The wiki is here and some presentations here.
This is in addition to the excellent comments from @RoryAlsop.
Disclaimer: I try to help (Doug & Scott) out on Security Onion.