The Network Statistics Daemon (NStats) is a GPL network data/network metrics graphing tool. It presents it's information via and HTTP interface. It's based in part on the Opensource work of NTOP by Luca Deri.
Open source project that offer summary and download services on this page is a project that carry out their development work on other open source development sites. Their work is linked to this page via a feature called OFI, and their work is not carried out here on OSDN site.