Worth Exploring: Akvorado Flow Collector and Visualizer
The results you can get when you know how to apply proper glue to a bunch of open-source tools never cease to amaze me. The latest entrant in that category: Akvorado, a Netflow/IPFIX collector and analyzer by Vincent Bernat.
Some of the sample graphs (shown in the GitHub repo) are not far off from those that knocked our socks off during the first Kentik Networking Field Day presentation. Definitely a tool worth exploring ;)
I still need to spend a bit of time reading docs to get filters and classifiers set up right, but early impressions after installing and pointing some flows at it are that this software is fantastic! I might finally retire my old as-stats server.