The Flow module provides the decoding function for NetFlow version 5,9
and IPFIX, and the encoding function for NetFlow version 9 and IPFIX.
It supports NetFlow version 9 (RFC3945) and NetFlow version 5
(http://www.cisco.com/) and IPFIX(draft-ietf-ipfix-protocol-26.txt).
Regretfully, it doesn't provide the full specification of IPFIX, yet.
It is future work. You can easily make the Flow Proxy, Protocol Converter
and Flow Concentrator by using the combination of both function. And also,
you can make the flexible Collector which can receive any Templates
by using the Storable perl module.

WWW: http://search.cpan.org/dist/Net-Flow/