NetFlow is a protocol developed by Cisco Systems that is used to record statistical, infrastructure, routing and other information about IP traffic flows traversing a NetFlow-enabled router or switch. A NetFlow collector is one of three typical functional components used for NetFlow analysis:
A NetFlow Collector’s main functions include:
NetFlow Collector and Netflow Analyzer applications are two functions of a NetFlow analysis system or product. In some cases, the NetFlow analysis product implements both functions on the same server. This is appropriate when the volume of flow data being generated by exporters is relatively low and localized.
In cases where flow data generation is high, or where sources are geographically dispersed, the collector function can be run on separate and geographically-distributed servers (such as rackmount server appliances). In these cases, collectors then synchronize their data to a centralized analyzer server.
Historically, the most common way to run NetFlow collectors was on a physical, rackmounted Intel-based server running a Linux OS variant. More recently, flow collectors have been deployed on virtual machines. Unfortunately, in either case, compute and storage severely limits the amount of detailed network flow data that could be retained and analyzed.
Most recently, a unified, cloud-scale approach to NetFlow collector and analyzer architectures has emerged. In this architecture, a horizontally-scalable, big data system replaces physical or virtual collector and analyzer appliances. Big data systems allow for dramatically higher volumes of data ingest, longer data retention periods, deeper network traffic analytics and more powerful anomaly detection. To learn more about big data NetFlow analysis, visit the Kentik Detect overview page.
Releated reading and resources:
Updated: June 5, 2019