Netflow viewers
FlowViewer / SiLK handles IPv6.
Web-based, graphical tracking and analysis. Free.
http://sourceforge.net/projects/flowviewer/
http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/software/release/3se/flexible_netflow/configuration_guide/b_fnf_3se_3850_cg/b_fnf_3se_3850_cg_chapter_010.html#reference_A9019899140647F2B3F87ABABCFC170D