Information about streams of data flowing through network devices is called NetFlow - the most widely-used standard for flow data statistics
Information about streams of data flowing through network devices is called NetFlow. Switches and routers, as well as other components collect and store information about the data transmitted within the network. This information concerns both logical, comprehensive flows between the source and target servers and physical point-to-point flows between key network elements.
NetFlow is a protocol developed by Cisco Systems, which is currently also known as the IPFIX standard – a component of Cisco IOS. NetFlow runs on IP devices (routers, layer 3 switches) and provides IP traffic statistics. This standard has been adopted by a number of manufacturers, e.g. Juniper makes a similar solution available under the name of jFlow. Other companies, such as HP, Foundry and Extreme, apply the sFlow data flow technology.
Regardless of the name, the NetFlow scope of data is substantial and constitutes a rich source of information updated in real time, which is always accessible and provides extensive knowledge on network data traffic. The system visualises not only the TCP/IP parameters in layers 3 and 4 (source, target IP address, protocol, port), but also additional traffic attributes, such as Type of Service, DSCP, source identifier and target AS areas in the BGP protocol, additional information about routing and traffic – next hop, input and output interfaces, source and target network address.