What is NetFlow?

NetFlow is a network protocol developed by Cisco for collecting IP traffic information and monitoring network traffic. By analyzing flow data, a picture of network traffic flow and volume can be built. Using a NetFlow collector and analyzer, you can see where network traffic is coming from and going to and how much traffic is being generated.

How NetFlow Works

What is the NetFlow protocol and how does it work? Click this image to open a NetFlow v9 datagram (PDF).
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NetFlow v9 Datagram Knowledge Series

What is a NetFlow Collector?

Routers that have the NetFlow feature enabled generate NetFlow records. These records are exported from the router and collected using a NetFlow collector. The NetFlow collector then processes the data to perform the traffic analysis and presentation in a user-friendly format. NetFlow collectors can take the form of hardware-based collectors (probes) or software-based collectors.

Other Flow Technologies

While the term NetFlow has become a de-facto industry standard, many other network hardware manufacturers support alternative flow technologies:
  • Juniper® (Jflow)
  • 3Com/HP® , Dell® , and Netgear® (s-flow)
  • Huawei® (NetStream)
  • Alcatel-Lucent® (Cflow)
  • Ericsson® (Rflow)

NetFlow Collectors

SolarWinds NetFlow Traffic Analyzer (NTA) is an example of a software-based NetFlow collector that collects traffic data, correlates it into a useable format, and then presents it to the user in a web-based interface.
  • What is the NetFlow protocol and how does it work? Click this image to open a NetFlow v9 datagram (PDF).
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Top 5 Reasons to Download NetFlow Traffic Analyzer

  1. Monitors network bandwidth & traffic patterns down to the interface level
  2. Identifies which users, applications, & protocols are consuming the most bandwidth
  3. Highlights the IP addresses of top talkers
  4. Analyzes Cisco® NetFlow, Juniper® J-Flow, IPFIX, sFlow® , Huawei NetStream™ & other flow data
  5. Typically deploys in less than an hour
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