For question about the NetFlow protocol.
NetFlow was initially implemented by Cisco, and described in an "informational" document that was not on the standards track: RFC 3954 – Cisco Systems NetFlow Services Export Version 9. The NetFlow protocol itself has been superseded by Internet Protocol Flow Information eXport (IPFIX). Based on the NetFlow Version 9 implementation, IPFIX is on the IETF standards track with RFC 5101 (obsoleted by RFC 7011), RFC 5102 (obsoleted by RFC 7012). Other vendors have proprietary protocols to do the same type of function.
