Free sflow software for windows

ntop is a network traffic probe that will show you the network usage ntop is a software very similar to the popular top Unix command and it is a network traffic probe that will show you the network usage. ntop is based on libpcap and it has been written in a portable way in order to virtually run on every Unix platform and on Win32 as well.
ntop users can use a a web browser (e.g. netscape) to navigate through ntop (that acts as a web server) traffic information and get a dump of the network status. In the latter case, ntop can be seen as a simple RMON-like agent with an embedded web interface.
The use of:
- a web interface
- limited configuration and administration via the web interface
- reduced CPU and memory usage (they vary according to network size and traffic)
- make ntop easy to use and suitable for monitoring various kind of networks.
Main features:
- Sort network traffic according to many protocols
- Show network traffic sorted according to various criteria
- Display traffic statistics
- Store on disk persistent traffic statistics in RRD format
- Identify the indentity (e.g. email address) of computer users
- Passively (i.e. withou sending probe packets) identify the host OS
- Show IP traffic distribution among the various protocols
- Analyse IP traffic and sort it according to the source/destination
- Display IP Traffic Subnet matrix (whos talking to who?)
- Report IP protocol usage sorted by protocol type
- Act as a NetFlow/sFlow collector for flows generated by routers (e.g. Cisco and Juniper) or switches (e.g. Foundry Networks)
- Produce RMON-like network traffic statistics
- VoIP support (SIP, Cisco SCCP and Asterisk IAX)
- NetFlow (including v5 and v9) and IPFIX support
- Network Flows
- Local Traffic Analysis
- Multithread and MP (MultiProcessor) support on both Unix and Win32
- Perl/PHP/Python lightweight API for accessing ntop from remote
- Support of both NetFlow andsFlow as flow collector. ntop can collect simultaneously from multiple probes.
- Traffic statistics are saved into RRD databases for long-run traffic analysis.
- Internet Domain, AS (Autonomous Systems), VLAN (Virtual LAN) Statistics
- Network assets discovery and categorization according to their OS and users
- Protocol decoders for most of known P2P (Peer to Peer) protocols
- Advanced per user HTTP password protection with encrypted passwords
- RRD support for persistently storing per-host traffic information
- Passive remote host fingerprint (Courtesy of ettercap)
- HTTPS (Secure HTTP via OpenSSL)
- Virtual/multiple network interfaces support
- Graphical Charts (via gdchart)
- WAP support
- U3 support and graphical GUI (Win32 only)
System requirements:
- From a few MB (little LAN) to 100 MB for a WAN.
- On a modern PC and large LAN, it is less than 10% of overall CPU load.