NetFlow is a network protocol developed by Cisco that collects IP traffic information and monitors network flow. It is a feature that was introduced on Cisco routers around 1996 that provides the ability to collect IP network traffic as it enters or exits an interface. NetFlow is used to record metadata about IP traffic flows traversing a network device such as a router, switch, or host. By analyzing NetFlow data, network administrators 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: a flow exporter, a flow collector, and a flow analyzer. The flow exporter aggregates packets into flows and exports flow records towards one or more flow collectors. The flow collector is responsible for reception, storage, and pre-processing of flow data received from a flow exporter. The flow analyzer processes and analyzes NetFlow records received and stored by a flow collector, turning data into reports and alerts that provide insight on bandwidth usage, traffic patterns, application usage, and other performance metrics that may identify security threats and performance problems.

NetFlow data provides deep visibility into a network, which helps optimize performance for better user experiences. NetFlow solutions are a commonly used standard for monitoring network flow data. NetFlow monitoring solutions are made up of three primary tools: an exporter, a collector, and an analysis application. NetFlow is a one-way technology, so when the server responds to the initial client request, the process works in reverse and creates a new flow record. NetFlow captures a number of details, including the timestamp of a flow’s first and last packets, the total number of bytes and packets exchanged, and a summary of the flags used in TCP connections.

In summary, NetFlow is a network protocol that collects IP traffic information and monitors network flow. It provides deep visibility into a network, which helps optimize performance for better user experiences. NetFlow solutions are a commonly used standard for monitoring network flow data and are made up of three primary tools: an exporter, a collector, and an analysis application.