OMNI is an SSL VPN and managed certificate authority system:
1. SSL VPN based on OpenVPN (you might say it's Enterprise OpenVPN)
2. SSL Certificate Authority - a x509 PKI system - securing VPN instances but also front-end servers
It's a great alternative to pricey Cisco/Juniper solutions (which are
also limited to one VPN instance terminated on the device - and have
no CA system).
OMNI has been covered in Polish Newseek and is used for instance by
one of Polish Army departments.