what Netlfow software is recommanded to use on Linux to export Netflow Data

what Netlfow software is recommanded to use on Linux to export Netflow Data

Hi team 

i use quagga to play Soft router on my Network it run on a Ubuntu 12.04 , and it has many gre tunnel virtual interface , 

now i want to export it Netflow to collector , and is there a recommanded suite for Ubuntu 12.04 ?