FastNetMon - FastNetMon is a very fast DDoS analyzer with sflow/netflow/mirror support.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
Arbor - Easily manage product development
Nfsen - NfSen is a graphical web based front end for the nfdump netflow tools that allows you to:
Abusix - Abusix is a network security company that offers email threat protection and network abuse handling solutions to ISPs, Telcos, and Cloud/Hosting Providers to stop the rapidly growing problem of email-borne threats and other kinds of network abuse.
Corero - Real-time, high-performance, automatic DDoS attack protection, on-premis and in the cloud, with comprehensive attack visibility, analytics, reporting.