What is "netflow"

NetFlow is a feature that was introduced on Cisco routers that provides the ability to collect IP network traffic as it enters or exits an interface. By analyzing the data provided by NetFlow, a network administrator can determine things such as the source and destination of traffic, class of service, and the causes of congestion. A typical flow monitoring setup (using NetFlow) consists of three main components:

• Flow exporter: aggregates packets into flows and exports flow records towards one or more flow collectors.
• Flow collector: responsible for reception, storage and pre-processing of flow data received from a flow exporter.
• Analysis application: analyzes received flow data in the context of intrusion detection or traffic profiling, for example.